Beer Glossary and Brewing Terms – Making craft beer from grains easy, clean and simple

Adjunct:	A beer adjunct or brewing adjunct is any unmalted grain or other fermentable ingredient that is used in the brewing process. Brewing adjuncts are often times used for the purpose of lowering overall brewing production expense or as a means of modifying aspects of a beer such as creating better head retention or enhancing the flavor of the beer. Some common used brewing adjuncts include rice, corn, sorghum, rye, oats, honey, fruits, and candi sugars.
Alcohol by Volume or ABV:	Alcohol by volume (ABV) represents what portion of the total volume of a liquid is alcohol. To calculate the ABV of a beer, you will want to subtract the Final Gravity from your Original Gravity and multiply by 131. The following is an example of how to calculate your alcohol by volume, assuming that your original gravity was 1.055 and your final gravity reading was 1.012. Example: 1.055 – 1.012 = 0.043 x 131 = 5.633% In this example your alcohol by volume worked out to 5.633%
Aerate or Aeration:	Aeration is the process of adding, mixing or injecting air or oxygen into the cooled wort immediately before or after the yeast has been pitched. When aerating your wort, it is critical to keep its temperature under 80 F in order to avoid hot side aeration which will oxidize the wort and potentially cause off flavors in your finished beer. There are several different ways to aerate your wort. The typical methods include injection and agitation.
Airlock:	An airlock or fermentation lock is a single direction sanitary valve used during fermentation that allows the large quantities of carbon dioxide being produced by the yeast to escape while not permitting outside air \ oxygen or contaminants to enter the fermentation chamber. This both creates a sanitary seal on the fermenter and helps prevent the oxidization of the fermenting beer. The airlock or fermentation lock is typically contains a sanitizer to help maintain the integrity of the fermenter. Airlocks tend to be made of clear plastic or glass so that the CO2 bubbles passing through it can be monitored as a way of gauging how active of a fermentation is occurring.
Alcohol by Weight or ABW:	Alcohol by weight (ABW) is the measurement of the alcohol content of a solution in terms of the percentage weight of the alcohol compared to the total weight of the solution. Since most of us are accustomed to thinking of beer in terms of alcohol by volume, you may find it beneficial to convert the alcohol by weight to alcohol by volume. To convert ABW to ABV, multiply the ABW by 1.25. For instance, an ABW of 5 equals an ABV of 6.25%. To convert ABV to ABW, you would multiply the ABV by .8.
Ale:	Ale is one of two primary beer varieties, the other being lagers. Ale is fermented using a top fermenting yeast. Ale yeasts are typically more resilient to warmer temperatures than their lager counterparts and are typically fermented at a temperature range between 65 F and 75 F. Since yeast is more active at higher temperatures, ales ferment much quicker than a lagers. Examples of ales include pale ales, India pale ale, golden ales, old ale, Belgian ale and barley wines. Something to keep in mind when fermenting an ale is that ale yeast can ferment beer above a temperature of 75 F, but when doing so it will often times create undesirable esters and off flavors. Also, liquid ale yeast is vulnerable to high temperature, and it should be refrigerated to maintain its viability in transit and in storage. Due to the delicate nature of liquid yeast, it is wise to create a yeast starter to verify its viability prior to pitching it in the cooled wort.
Alkaline or Alkalinity:	Simply put, alkaline or alkalinity refers to the pH of a solution registering greater than 7 and its capacity for neutralizing an acid solution. In order to boost the alkalinity in a mash and offset acidity, you would most commonly add a carbonate or bicarbonate such as the brewing additive calcium carbonate \ chalk.
Alpha Acid:	Alpha acid is one of the two soft resin acids that are present in hops. The alpha acids in hops are found in the resin glands of the flowers. Alpha acids are the primary source of the hop bitterness. In addition to their bittering properties, alpha acids also act as preservatives in beer and function as a mild anti bacterial agent. When heated in the brewing process, alpha acids are isomerized and form iso-alpha acids. The amount of time that the alpha acid is subjected to the boil determines the degree of isomerization that occurs and the amount of bitter flavoring that is produced in the beer. At a certain point, the boiling begins to experience diminished returns on the isomerization of the alpha acid and becomes ineffective at creating additional bitterness in the beer. Typically that diminished effect occurs after 60 to 90 minutes of the hop being added to the heated wort. The isomerization process occurs in the wort when it is heated above approximately 175 F. The quantity of alpha acid present in a hop will determine the hops bittering potential. Alpha acid percentages vary dramatically between the different varieties of hops and are impacted by a multitude of outside factors including packaging, age of the hop, storage temperature, oxidization, drying method, and growing conditions. The most common alpha acids are humulone, adhumulone, cohumulone, posthumulone, and prehumulone.
Amylase:	Amylase is an enzyme group that is responsible for hydrolizing and converting starches into sugars. The two primary amylase enzymes are alpha amylase and beta amylase, which digest and break down the polysaccharides into smaller disaccharides and then monosaccharides. To help facilitate the breakdown of unfermentable sugars, amylase may be added to fermentation at the same time you pitch your yeast. This will create a lower final gravity and a dryer finish.
Apparent Attenuation:	Apparent attenuation is the measurement of the percentage of sugars that have been converted to alcohol by the yeast in a beer. It is important to note that different yeast varieties will be capable of different levels of attenuation. Apparent attenuation is equal to the original gravity minus the final gravity divided by the original gravity, showing the percentage of conversion. A typical apparent attenuation range is between 65 and 80%. Apparent attenuation calculation example: Original Gravity of sample beer = 1.06 Final Gravity of sample beer = 1.012 Calculation: 1.06 – 1.012 = .048 .048 / .06 = 80% Apparent AttenuationThere are a variety of ways to impact your apparent attenuation. Some of these include the type of yeast you use, the amount of yeast you pitch, your mash temperature(s), your grain bill composition, and your mash PH. If you are doing extract brewing, then the primary impacts will come from your yeast and any unfermentable sugars that you may add, such as maltodextrin.
Astringency or Astringent:	Astringency or astringent flavors are typically associated with a dry or puckering mouthfeel caused by excessive tannins and oxidized phenols. The tannins, which are a type of polyphenol, bind the salivary proteins and create a dry sensation in the mouth. A few examples of astringent flavors include acacia, sage, and distilled vinegar. A common cause of astringent off flavors is a mashing or sparge temperature that exceeds 170F or problems with pH levels during the mash and sparge.
Autolysis:	Autolysis is the destruction of a cell by the actions of its own enzymes. In brewing, autolysis typically occurs when yeast cells either decay over time or destroy each other. When the outer wall of the yeast cell is degraded and can no longer contain itself, it releases off flavors and odors into the beer. These odors are typically described as rubbery in aroma. Autolysis is most common in aged beers, but can also occur in a fresh beer due to a variety of factors including unhealthy yeast, aged yeast, stress caused by too rapid of a fermentation, excessive temperature changes and high alcohol levels. One of the best ways to reduce the impact of autolysis is to conduct a secondary fermentation and cold crashing your beer as a means of removing the beer from the yeast cake. Other ways of reducing the impact of autolysis is proper aeration of the wort prior to fermentation, avoiding oxidization, keeping a consistent and appropriate fermentation temperature, and properly regulating the temperature of your finished beer.
Barley:	Barley or the barley grain is the seed of the barley plant. It is a member of the grass family and is considered a cereal grain. There are two main classifications of domesticated barley, two-row and six-row. Two-row barley has a lower protein content but higher fermentable sugar content then six-row barley, but both are commonly used in brewing.
Beer:	Beer is an alcoholic beverage produced by the fermentation of malt, grain and adjunct sugars. Hops are typically added to beer to offset the malt sweetness, but sometimes herbs or spice may be used as an alternative.
Beer Engine:	A beer engine is a traditional hand-powered pump that is used to transfer beer from a cask to a serving spout.
Beta Acid:	Beta acid is one of the two primary resins that are present in hops, the other being alpha acid. Although beta acid imparts only a small portion of the bitterness that alpha acid provides, it is important because, as the alpha acid bitterness breaks down over time during fermentation and storage, beta acid creates a sharper bitterness in beer as oxidation occurs. Unlike alpha acid, beta acid does not isomerize during the boil and is primarily responsible for the hop aroma in a beer.
Blending:	Though not as common in all styles of beer, blending is very important when making beers such as sours or when brewing on the macro level. Blending allows you to achieve your desired flavor or color profile by blending two or more batches of beer together. In some cases, beers of dramatically different ages will be mixed together, like in the case of Rodenbach Grand Cru, where their young ale is mixed with their wood vat two year old ale to create a fuller taste.
Blow Off Tube:	A blow off tube is a type of high flow airlock where a tube and bung or seal are placed at the high point of a fermenter that leads to a reservoir where the end of the tube is placed beneath a sanitizing solution. This allows for the expulsion of co2 and excess fermentation foam and fermentation solids. A blow-off is a great airlock to use when you have minimal head space available in your fermenter and or if you are concerned about a rapid or high foam fermentation. If you ever walk out to your fermenting beer bubbling out of a traditional two or three part airlock, a blow-off would be better alternative to use in that situation, as it allows for a greater amount of carbon dioxide and foam transmission while still maintaining a sanitary environment. A blow-off is rarely necessary in a secondary fermentation unless you are providing additional fermentable sugars at that point.
Body:	Body in brewing and beer terms is often described as the thickness or viscosity of a beer as judged by your mouth. The body of a beer is typically described as thin, medium or full. Different varieties of beer are assumed to have a specific body profile; for instance a light lager or pilsner would be expected to have a thin body profile, whereas a stout would have a full body. The term mouthfeel is oftentimes used synonymously with body. Determining factors in defining and making up a beer’s body include proteins, carbonation level, unfermentable sugars such as maltodextrin, water profile, and alcohol level.
Boil:	The boil is the stage of the brewing process during which the sweet wort is boiled in the brew kettle and hops are added. When hops are added to the boil, hop resin/alpha and beta acid isomerization occurs, which imparts bittering and hop aroma in the finished beer. A typically boil time lasts between 60 and 90 minutes. The longer the hops isomerization in the boiling wort, the greater the potential for bittering that exists. In addition to hop isomerization, the boil also sterilizes the wort, denaturing the enzymes that were active in the mash. The boil is also responsible for the hot break, which removes several unwanted compounds that can cause both unwanted flavors in chill haze.
Bottle Conditioning:	Bottle conditioning refers to the process by which the beer is naturally carbonated in the bottle as a result of fermentation as opposed to being carbonated prior to filling. Oftentimes additional sugar or krausen is added to the beer prior to bottling or directly to the bottle so that the yeast will have enough sugar available to properly carbonate the beer. A suitable fermentation temperature must be maintained for the conditioning beer to allow the yeast to adequately carbonate the beer. Since viable yeast is present in a bottle-conditioned beer, this provides an additional component of flavor that develops further as the beer ages. A slight layer of yeast on the bottom of a bottle of beer may be a sign that the beer had been bottled conditioned, but may also be due to poor filling or residual clarification of a non-filtered beer. The bottle and cap should always be sanitized before bottling occurs.
Bottom Fermenting:	Bottom fermentation or bottom fermenting is a term that describes the manner in which lager yeast tends to collect on the bottom of the fermenter and conducts its fermentation, as opposed to top fermenting ale yeast, which conducts most of its fermentation on the top of the beer. Bottom fermenting lager yeast strains prefer a low fermentation temperature range that is typically between 40 F and 55 F, but varies between strains.
Brettanomyces or Brett:	Brett or brettanomyces is a high attenuation yeast strain that is known for the acidic, funky, wild\barnyard type tastes and smells that it produces. In most beer styles, brett it is perceived as an unwanted contaminant due to its strong and distinct flavors that can overwhelm more subtle beer flavors. Yet it is highly prized in some Belgian ales, such as gueuze, lambics, farmhouse ales, and Flanders red ales. It is even used in one of my favorite Belgian Trappist beers called Orval, where their brewers add it at bottling, and allow it to ferment out and condition over time. Brettanomyces has grown in popularity over the last several years and is now used in a wide variety of styles and by many US craft breweries. When brewing with brett, it is important to avoid cross contamination with your non-brett beers as it is a robust yeast strain that can easily modify a beer’s flavor and aroma. The most commonly used brett yeast strains are White Labs WLP644 Brettanomyces Bruxellensis Trois, White Labs WLP645 Brettanomyces Clausenii, White Labs WLP650 Brettanomyces Bruxellensis and Wyeast 5526 Brettanomyces Lambicus.
Brewing Sculpture or Beer Rack:	A home brewing sculpture is another term for a home brewery. Most home brewing beer sculptures consist of a hot liquor tank, mash tun and a boil kettle. The brewing sculpture shown below is a single tier sculpture that utilizes pumps to transfer liquid at different stages of the brewing process from one tank to another. Each tank has a separate propane fueled burner beneath it to apply heat when needed.
Bright Beer:	Bright beer is beer that has fully clarified, is free from haze and nearly all particulates and yeast has fallen out of suspension.
Buffer:	A buffer or buffer solution, as related to pH, is typically a solution consisting of a weak acid and its conjugate base, or a weak base and its conjugate acid. The purpose of the buffer is to decrease the impact to pH when a differing acid or base is introduced to the solution. PH plays an important role when it comes to a brewer’s mash. You will find brewing pH stabilizers available on the market, such as pH Stabilizer 5.2, which is a sodium phosphate salt-based buffer; please be aware that there is a great deal of disagreement about how beneficial or detrimental they actually are. Ideally, you would control the mash pH of each individual beer style by comparing your home water profile to that of the desired water profile of the beer you are brewing, and make the appropriate water adjustments that way. Additionally, some of the popular home brewing software on the market will also help you determine the proper water additives based on the estimated pH level of the grain bill that you are brewing with. Lastly, there are a variety of pH measuring strips and meters available on the market, which can help you determine if adjustments need to be made to your mash.
Burner:	A burner is a natural gas or propane fuel direct flame heating device use for home brewing and some very small micro breweries. Most home brewing burners range anywhere from 55,000 BTU to 92,000 BTU.
Calcium Carbonate or CaCO3:	Calcium carbonate or CaCO3 is precipitated chalk. It is typically used in brewing as a water adjustment to increases the pH of a mash. You will want to verify with your vendor, but 1 gram per gallon usually adds 106 ppm calcium and 158 ppm carbonate.
Calcium Chloride or CaCl2:	Calcium chloride or CaCl2 is used as water additive to reduce the pH of a mash. One gram per gallon typically adds 72 ppm of calcium and 127 ppm of chloride, but you will want to verify those numbers with your vendor.
Calcium Sulfate or CaSO4:	Calcium sulfate or CaSO4 is also known as gypsum. It can be used to boost sulfate or add permanent hardness to a mash. You will want to verify with your vendor, but one gram per gallon typically adds 62 ppm calcium,147 ppm sulfate, and 153.5 ppm to the permanent hardness.
Carbonation:	Carbonation or carbonating is the process of dissolving carbon dioxide in beer. There are different methods of carbonating beer, but the end effect is basically the same from a CO2 standpoint. Carbon dioxide is built up under pressure, which carbonates the beer; when the pressure is reduced, the carbon dioxide is released as bubbles into the beer. Carbonation helps form the head of the beer and makes the beer effervescent. Carbonation has a significant impact on many aspects of a beer, from the body and mouthfeel to the aroma delivery and appearance. Some of the different methods for carbonating beer include krausening, force carbonation and bottle priming.
Carboy:	Carboys are large jug-shaped containers typically made of glass or plastic. They are used in brewing for small batch fermentation. Carboys usually range in size anywhere from 1/2 gallon to 6 1/2 gallons. An air lock and stopper or rubberized bung are typically placed at the top of the carboy to create a seal that allows CO2 to escape from the fermenting beer, while still maintaining a sanitary environment inside the carboy. Glass carboys are airtight, which can be better than air permeable plastic carboys, but glass carboys are also more fragile and dangerous to work with. Additionally, glass carboys are also less susceptible to internal scratching since their surface is much harder than that of a plastic carboy.
Cask Conditioning:	Cask conditioned beer refers to unfiltered and unpasteurized beer that has been conditioned in and served from a cask. This method will impart a distinctive flavor. Cask conditioned beer is naturally fermented and is typically served from the cask using a beer engine or hand-powered style pump as opposed to pushed using a CO2 tank. Cask beers tend to be served with lower levels of dissolved CO2 than one might find in a typical kegged beer. The shelf life of a casked beer is also much shorter, and the potential for oxidization is much higher since the cask walls are air permeable.
Cellulose:	Cellulose is the most abundant organic polymer on earth, and the primary content in a beer’s trub. Cellulose is unfermentable, tasteless, and odorless. It is a solid, and much of it will drop out of the beer during primary fermentation, where it sinks to the bottom of the fermenter and helps to form the trub bed. The primary contributors to a beer’s cellulose content are fibrous materials like grain husk and hop leaf.
Chill Haze:	Chill haze is the cloudy or hazy appearance that a chilled beer gets when it is too high in residual proteins or tannins. For the most part, haze and turbidity are highly undesirable unless you are brewing a beer such as an American wheat, hefeweizen, or Belgian wit, where the style calls for a certain amount of haze. It is easier to try and avoid chill haze as opposed to trying to remove it from a beer. Best practices for avoiding chill haze include properly controlling your mash out, sparging, lautering, and recirculation temperatures. Tannin extraction becomes a real issue when you exceed a temperature of 170 F in your mash tun, so always do your best to keep your sparge temp near 168 F for proper sugar extraction, but do not exceed it or else you will risk stripping too much tannin from the grain. A consistent rolling boil and hot break are also important when it comes to reducing excess proteins. During the boil and hot break, proteins will merge together, becoming very dense and dropping out to the bottom of the kettle where they can be separated and not transferred to the fermenter. Perhaps one of the best and easiest ways to help avoid chill haze is to use an inexpensive fining such as whirlfloc. Whirlfloc is my personal favorite haze clearing fining; it is a blend of Irish moss and purified carrageenan. The Irish moss and carrageenan bind with the proteins and aid in precipitation. I will typically use one tablet per 5 to 15 gallons and add it at the last 15 minutes of the boil. If you find yourself in the situation where when chilled your beer has haze and you have not yet bottled it, you can try one of the following methods to help clear chill haze. Extend your conditioning time and cold crash your beer to 34 F for a couple of weeks. This will aid in precipitation and help move suspended yeast and protein to the bottom of the vessel so that you can rack or transfer the clarified beer off the top of it. As a last ditch effort, you can use a beer clarifier such as gelatin. The gelatin should bind to the excess proteins, and drop some of the haze out of your beer.
Cloying:	Cloying is a term used to describe a beer that is too sweet or too malty. This typically occurs when there were not enough hops to properly balance out the sweetness, if the mash temp was set too high and created too many unfermentable sugars, or if the yeast was not able to carry out a proper fermentation and too much sugar was left behind in the finished beer.
Cold Crashing:	Cold crashing is a common method used to clarify beer. When a beer is cold crashed, it is chilled down to approximately 35 F and left for several days to several weeks. During that time, yeast and other solids tend to clump together and fall to the bottom of the fermenter or holding tank. The clarified beer is then racked above the layer of sediment. Cold crashing is not appropriate for some beer such as American wheat beers or Belgian wit ales where a yeasty flavor or hazy beer is desired.
Cold Filtering:	Cold filtering or cold crashing is a common method used to clarify beer. When a beer is cold filtered, it is chilled down to approximately 35 F and left for several days to weeks. During that time, yeast and other solids tend to clump together and fall to the bottom of the fermenter or holding vessel. The beer is then racked above the sediment layer and potentially passed through a filter if additional clarifying is desired. Cold filtering is not appropriate for some beer styles, such as hefeweizens or certain Belgian ales where a yeasty flavor or hazy beer is desired.
Color:	The color or colour of a beer is typically described using either the Standard Reference Method scale (SRM), Lovibond scale, or European Brewery Convention (EBC) scale, which reference a numerical value to define the color and shade, and in some cases clarity or turbidity of a beer. The higher the number, the darker the referenced color is. A beer’s color is primarily composed from the pigments of the grains that make up its grain bill. The pigment of a grain will darken if it is toasted, caramelized, or roasted, and that will impart that color on the finished beer. In the case of an imperial stout, the roast of the malt is so dark that it makes the beer nearly black. It is important to remember that as the color of the grain darkens, the acidity typically increases. Beer can also gain color from adjuncts, such as fruits and sugars.
Conical:	A conical or conical fermentor is a fermentor that is cone shapped on the bottom to allow the yeast and heavy particles that are in the beer during fermentation to fall to the bottom of the fermenter so that they can be removed or so that the yeast can been havested for future batches of beer. The cone shapped bottom also helps insure that you can get as much usuable beer as possible during transfers.
Conditioning:	Beer conditioning typically occurs after primary fermentation has completed, and the beer has been racked off the yeast and trub bed to a different vessel such as a secondary fermenter, barrel, keg, holding tank, cask, or bottle. The beer then conditions over time; the length of time typically depends on the style of beer, and the type of conditioning that is desired. If you are brewing an American wheat or perhaps a dry hopped pale ale, where a very fresh taste or aroma may be desired, then you would want a minimal conditioning time. But if you are brewing a barrel aged stout or a Flanders red sour, you may need to allow the beer to condition for over a year depending on the conditioning environment and desired flavors.
Dextrin:	Dextrins and in this case specifically maltodextrins, are a group of mostly unfermentable carbohydrates produced by the partial hydrolysis of starch or glycogen. Dextrins and maltodextrins typically impart little to no flavor upon the finished beer, but are important because they can be a valuable method for adding gravity and perceived body and mouthfeel to a beer. This can be extremely helpful when you are brewing a heavy adjunct based beer such as a gluten free ale that might have a thin body. Maltodextrin is often made from corn, and a typical composition will be .5% dextrose, 2.5% Maltose, 3.5% maltoriose, 93.5% higher saccharides. You will want to consult your vendor for actual numbers.
Diacetyl:	Diacetyl is a naturally occurring compound formed during fermentation and has a perceived butter or butterscotch like flavor that is undesirable in most beers. It is important to note that other ingredients used in beer production such as caramelized grains may impart a somewhat similar flavor and the two should not be confused. Although Diacetyl is tolerated or even expected in some beer styles, recent research has shown that at very high levels and under the right conditions it can be toxic. The good news is that diacetyl is typically only present at very low levels in beer and can be highly minimized if certain protocols are adhered to. One way to help reduce diacetyl in your beer is proper equipment cleaning and sanitization as certain typically undesirable bacteria’s produce diacetyl. Another way or reducing the diacetyl in your beer is to pitch a sufficient quantity of healthy yeast and conduct a full fermentation and conditioning cycle prior to cold crashing or kegging your beer. Yeast is both responsible for creating and removing diacetyl at different stages of the fermentation process. Yeast creates diacetyl early in the fermentation process and breaks it down towards the end; so if you did not pitch enough healthy yeast to complete the fermentation, placed your yeast in stasis or destroyed your yeast prior to allowing the fermentation to complete then you may end up with higher then desired levels of diacetyl. If you happen to be fermenting a lager, a process known as a diacetyle rest which requires a fermentation temperature increase may also be helpful in reducing diacetyl in your beer.
Draught Beer or Draft Beer:	Draught beer or draft beer is beer that is served via pressurized line or hand pump \ beer engine from a holding tank, barrel,keg or cask to the glass as opposed to poured from a bottle or can.
Dry Hop or Dry Hopping:	Dry hop, dry hopping or dry hopped beer is beer that has had hops added to it during fermentation as a way of increasing hop aroma. Dry hopping is typically conducted in secondary fermentation or after primary fermentation has completed to help assure that the aroma stays in the fermenter as opposed to being pushed through the airlock with the escaping CO2. When dry hopping, little to no bitterness is added to the fermenting beer as the alpha acid resin is relatively insoluble in a fermenting beer at that fermentation temperature. The process of dry hopping typically lasts anywhere from a few days to a couple of weeks. Some brewers report that their beer acquires a grassy flavor if it is allowed to dry hop for more than a week or so. If grassy off flavors are of concern you can always add additional hops for a shorter duration of time to achieve the desired dry hop aroma.
Diastatic Power:	Diastatic power or enzymatic power is the measurement of how much starch converting enzyme a malted grain contains and is shown in degrees Lintner. If your mash does not contain an adequate amount of diastatic power, you will not convert a high enough portion of the starch if your grain bill to sugar which will translate to a low brew house efficiency and lower than expected starting gravity. To be safe you should aim for an average of at least 75 degrees Lintner for your total grain bill. For the most part light base malts are used to make up the real diastatic power of a mash. Caramelized, toasted and roasted malts have diminished diastatic power due to excessive heating and the darker the roast of the malted grain the less diastatic power it will tend to have.
Dry Malt Extract:	Dry Malt Extract or DME is typically used in extract beer brewing, for yeast starters and in some cases all grain brewing. To make dry malt extract, the sugars from a brewing mash are transferred from a mash tun or lauter tun and completely dehydrated and in a vacuum chamber. Typically no hops are added to a malt extract.
Ester:	An ester is chemical flavor compound that is created during the fermentation process. Ester formation is primarily dependent on the yeast strain. In some cases excess esters are considered an off flavor and in other instances it is desired like in the case of a Bavarian hefeweizen where banana and clove tasting esters are expected. Esters are typically described as fruity, flowery or spicy scents and flavors in a beer.
False Bottom:	A home brewing false bottom is a perforated or slotted screen \ shield on the bottom of a mash tun or lauter tun that restricts grains from being collected with the wort when it is drawn from the mash in preparation for the boil.
Fermentation:	Beer fermentation is the metabolic conversion of malt and adjunct sugars to alcohol, acid and CO2 using yeast or bacteria. As yeast and bacteria convert the wort sugars, approximately equal amounts of carbon dioxide and alcohol are produced. The alcohol being produced by the yeast is less dense then the sugars and water the yeast is metabolizing so the gravity of the fermenting beer drops while fermentation continues to occur. The two predominant types of fermentation are top fermenting which is used for ales and bottom fermenting which is typical for lagers. The time frame it will take for a fermentation to complete is dependent on a great many factors, just a few of them include the types of sugars that the wort is composed of, the amount of sugar in the wort / original gravity, the type of yeast and or bacteria used, the amount of yeast and or bacteria used, the health of the yeast and or bacteria and temperature the fermentation occurs at. Most fermentations will take approximately 2 to 6 weeks to complete but some may take upwards of a year before the beer is considered ready.
Fermentation Lock:	A fermentation lock or airlock is a single direction sanitary valve used during fermentation that allows the large quantities of carbon dioxide being produced by the yeast to escape while not permitting outside air \ oxygen or contaminants to enter the fermentation chamber. This creates both a sanitary seal on the fermenter and helps prevent the oxidization of the fermenting beer. The fermentation lock typically contains a small amount of liquid sanitizer to help maintain the integrity of the fermenter. Fermentation locks tend to be made of clear plastic or glass so that the CO2 bubbles passing through it can be monitored as a rough way of gauging how active of a fermentation is occurring at a given time.
Final Gravity:	The final gravity or FG of a beer is the beers specific gravity measured once fermentation has completed. Once a brewer has the final gravity, it can be compared to the original gravity and the ABV or alcohol by volume can be calculated. The final gravity of a beer is typically taken using a hydrometer or refractometer. Specialty final gravity hydrometers are available to allow you to take a more accurate reading of your final gravity if desired.
Finings:	Most commonly finings are substances added to wort or beer for the purpose of clearing or clarifying a beer. Some examples of beer clarification finings are whirlfloc, isinglass, Irish moss, bentonite, gelatin, kieselsol, chitosan and carrageenan. Most finings work as a binding agent, clumping together with residual proteins, solids, yeast and tannins and sinking to the bottom of the kettle, fermenter or holding vessel so that they can be excluded from the finished beer. In some cases the finings can also be used to enhance flavor or aroma, by reducing sometimes undesirable particulates like tannins.
Flocculation:	Flocculation refers to a yeast strains tendency to clump together and drop out or fall out of suspension to the bottom of the fermenter or holding vessel. As yeast flocculates, the beer begins to clarify. Some yeast strains tend to have high flocculation such as Wyeast Scottish #1728, while other strains like Wyeast American Wheat #1010 or very low flocculation. The physical appearance of the yeast cell plays a big part in its flocculation level. It is important to choose a yeast with an appropriate flocculation profile when designing a beer; for instance you would not pair a Belgian Wit wort with a high flocculation yeast, as you want some of the yeast to stay in suspension in the finished beer.
Fresh Hopping:	Fresh hopping a beer is when freshly picked \ undried hops are added to a beer at some point of the brewing, fermentation or conditioning process. These hops are typically added to the beer within a day or two of being picked to maximize the unique flavors extracted from a freshly picked hop. A fresh or wet hop is typically less predictable then a dried hop and will usually impart lower amount of bitterness then the same weight dry hop due to the additional moisture weight in the wet hop.
Fusel Alcohol:	Fusel alcohols are typically considered to be off flavors that imparts harsh hot alcohol, solvent or mineral spirit like tastes in your beer. Fusel alcohols in beer are often the result of excessive fermentation temperatures that lead to accelerated initial yeast production and rapid fermentation. In addition to the off flavors they create, some believe that fusel alcohols may contribute to head aches and hangovers.
GFCI Adapter:	A GFCI or Ground Fault Circuit Interrupter is a device that cuts the flow of electricity when the electrical current is not balanced between the energized conductor and the return neutral conductor.
Gluten:	Gluten is a protein composite found in grains such as barley, rye and wheat.
Graf:	Graf or Graff is a cider that has had hops added or a beer that has had apple juice or cider add to it.
Grist:	A beers grist is the milled or crushed malt and grain that comprise the grain bill prior to the mashing process. An examples would be, the beers grist contained crushed American two row malted barley, German pilsner malt and some white wheat malt.
Grain Bill:	A grain bill or mash bill is the whole of the different malts, grains and adjuncts that make up a beer. The grain bill is very important when designing a beer recipe as it is primarily responsible for the potential original gravity, color and diastatic power of the beer.
Growler:	A Growler is a large capacity beer container that is typically made of glass, ceramics, or stainless steel. In the late 1990s, growlers began gaining in popularity at craft breweries and brewpubs as an easy way for patrons to take beer home when traditional bottling was not a reasonable option. A typical growler holds 64 or 68 fluid ounces, but they come in a variety of sizes. The top of the growler creates an airtight seal using either a screw cap or a hinge/latch style cap and can keep beer fresh for over a week if maintained properly.
Head Retention:	Head retention is a beers ability to retain its foamy head once the beer has been poured. In most styles of beer a thick foamy head that does not dissipate too quickly is very desirable. The three primary factors that impact a beers head are the carbonation level of the beer, residual proteins that form the body of the finished beer and isomerized humulones pulled from the hops that were added during a beers boil. Hops that are added during fermentation or once the beer has cooled below approximately 175 F, will not isomerize and will have very little impact on head retention. A stronger or hoppier beer will tend to have better head retention because it will usually have more residual proteins and a greater amount of isomerized humulones. The most common ways of enhancing a beers head retention is to add high alpha acid hops during the boil, utilizing grains such as crystal malts or wheat or adding an adjunct such as maltodextrin to your boil. Striking the right balance is a bit of an art as you do not want to compromise the taste of your beer or risk clarity issues by pushing too hard for good head retention.
HERMS or Heat Exchanged Recirculating Mash System:	A HERMS or Heat Exchanged Recirculating Mash System is a mash recirculation system that regulates mash temperature by pumping the wort from the mash tun through a heat exchanging tube or coil inside of the hot liquor tank or a secondary heating tank. The wort then flows back into the mash tun to maintain the mash temp without applying direct heat to the mash tun.
Hops:	Hops are the cone shaped flowers of the hop plant humulus lupulus and are responsible for the bitter taste and much of the aroma in a beer. The first documented cultivation of hops occurred in 730’s AD, in the Hallertau region of Germany, but by most accounts were not widely used in beer brewing until approximately 350 years later. Today there are well over 80 unique varieties of hops that are commonly used to brew beer. The lupilin glands of the female hop flower are where the soft resins and oils used to bitter beer and impart aroma are contained. The hops resin is comprised of alpha and beta acids. The alpha acid in hops are the primary source of the hop bitterness and also acts as a preservative in beer. When heated in the brewing process, alpha acids are isomerized and form iso-alpha acids. The amount of time that the alpha acid is subjected to the boil determines the degree of isomerization that occurs and the amount of bitter flavoring that is produced in the beer. At a point the boiling begins to have significantly diminished returns on the isomerization of the alpha acid and becomes ineffective for creating additional bitterness in the beer. Typically that occurs after 60 to 90 minutes of the hop being added to the heated wort. The isomerization process occurs when the wort is heated above approximately 175 F. The quantity of alpha acid present in a hop will determine the hops bittering potential. Alpha acid percentages vary dramatically between the different varieties of hops and are impacted by a multitude of outside factors such as storage packaging, age of the hop, storage temperature, oxidization, drying method and growing conditions. Unlike alpha acid, beta acid imparts only a small portion of the total bitterness in a beer, yet beta acids it is important because as the alpha acid bitterness breaks down over time during fermentation and storage, beta acid creates a sharper bitterness as oxidation occurs. Unlike alpha acid, beta acid does not isomerize during the boil and is primarily responsible for the hop aroma in a beer.
Hopback:	A Hopback or hop back is a small hop filled vessel, typically made of copper or stainless steel that is usually placed between either the brew kettle and wort chiller or brew kettle and fermentation chamber. It is highly recommended that you place the hopback between the brew kettle and chiller if an external chiller is being used. If the beer is first chilled, then the wort flowing over the hops will be far less effective at extracting the resins and oils from the hops; since the temperature of the wort would be under 170 F, the alpha acids will not isomerize, so no bitterness will be imparted on the wort and at a reduced temperature the aromas extracted from the hops will be diminished as well. Whole hops are typically recommended or required for using most hopbacks as pellet hops are more prone to clogging and a good deal of the particulates from pellet hops will end up in your fermentation vessel. In addition to adding hop flavor and aroma to your wort, a hopback is also a valuable tool for filter the hot break and or cold break from your brew kettle to your fermenter. As the wort passes through the hopback, the hops will work as an organic screen, capturing many of the larger protein and particulate masses that enter it.
Hot Break:	Hot break is the clumping of proteins, solids and tannins that fall out of the wort during the boil and eventually collect at the bottom of the kettle. A steady boil is the key to achieving a good hot break which will typically occur 5-15 minutes after the boil begins. When the foam on top of your boil finally dissipates, you know that much of the proteins have coagulated and that your hot break has occurred. A hot break is important because it aids in removing undesirable and potentially off flavor causing tannins and compounds from the boil. It also helps improve clarity and reduces the risk of chill haze down the line.
Hot Liquor Tank:	The hot liquor tank or HLT is a brewing vessel used to heat water for different stages of the brewing process including the mash and sparge. The hot liquor tank is typically heated by either gas, steam or an electric heating coil. Depending on brewery configuration, the hot liquor tank may hold water at temperatures as high as 170 F, or possibly even higher in cases where a boil is conducted to modify the mineral composition of the brewing water in order to remove bicarbonate.
Hydrometer:	A hydrometer is an instrument used to measure the specific gravity of liquid in comparison to pure water. The hydrometer is important because it allows a brewer to determine when the mash is no longer contributing sufficient levels of sugar during a sparge, how much dissolved sugar is in a brewers finished wort, what the brew house efficiency is, what the original gravity of a beer is, how a fermentation is progressing, when fermentation has completed, if your beer has under or over fermented, what the final gravity of a beer is and also gives you the information needed to calculate your Alcohol By Volume.
IBU or International Bittering Units:	IBU or International Bittering Units is a measurement showing the actual, not perceived bitterness that the alpha acids from hops have imparted on a beer. The strength, sweetness and maltiness of a beer impacts the way our taste buds perceive the alpha acid bitterness in the beer. Typically the stronger or maltier a beer tastes, the less we perceive the bitterness, so a brewer must balance the beer with additional hops or a longer boil time to compensate. Below is a listing of common IBU levels that you can expect from different beer styles. The international bittering units are important when designing a beer as you want to make sure you do not add too many or too few international bittering units, creating a beer that is not consistent with the style you are attempting to brew. Knowing the typical IBU of a style of beer may also be helpful when ordering a beer so that you can select a beer with a bitterness level that you find most enjoyable.
Infusion Mashing:	Infusion mashing is the process of regulating mash temperature by injecting heated water from the hot liquor tank into the mash tun at specific times. When conducting a step infusion mash, differing temperatures and quantities of water are infused in the mash tun from the hot liquor tank at specific intervals or steps in the mash process to control sugar conversion and extraction. When conducting a single infusion mash, the room temperature of the grains is compared with the desired mashing temperature and mash water volume. The hot liquor tank is then preheated to the appropriate temperature and the mash water is infused with the grains all at one time. The mash is then maintained at a constant temperature until the mash out or sparging sequence begins. RIMS or Recirculating Infusion Mash System is a mash infusion system that either utilizes a pump to recirculate the fluid in the mash over a secondary heat source (outside of the mash tun) to maintain the mash temperature or constantly recirculates the mash onto itself while direct heat is applied to the mash tun to regulate temperature. The fluid is pumped at a rapid enough pace to keep the temperature of the mash at an equilibrium and prevents the wort from being scorched or over heated.
Irish Moss:	Irish moss, a beer fining agent, is a blend of seaweeds used to clarify beer. I works by making the smaller molecules in the wort aggregate into larger particles and then fall out of suspension where they collect on the bottom of the brew kettle. Typically 1 tsp per 5 gallons of wort is added 15 minutes before the end of your boil.
Keg:	Kegs are cylindrical beer storage vessels that are typically constructed out of stainless steel or aluminum. They come in a variety of sizes from 2 gallons, all the way up to a full size 1/2 barrel keg at 15.5 gallons. I like to consider a keg to be a home brewer’s best friend. The primary benefit of a keg over bottles is the convenience. There is only one container to clean, sanitize, fill and carbonate; kegs are also very durable and allow you to modify your carbonation level if desired. Most home brewers use a version of a 5 gallon keg known as a corny keg or Cornelius keg. Below is a photo of three varieties of 5 gallon kegs. On the left is a 5 gallon ball lock Cornelius keg, in the center is a 1/6th barrel keg (that you would typically receive from a large scale or craft brewery) and to the right is a pin lock conversion keg; all hold approximately 5 gallons of beer. The ball lock kegs tend to be most common and prized by home brewers. I personally use both ball lock and pin lock kegs that have been converted to ball lock so that they are compatible with my CO2 system. I use my pin lock conversion kegs as fermentation vessels in my temperature controlled fermentation freezer. The pin lock kegs are shorter and wider which allows me to fit them in my fermentation freezer without the need of a collar extension for the freezer. Special air locks are available for use with the keg style fermenters; I only use them as a secondary fermenter due to the reduced head space available for the foam created during primary fermentation.
Kilning:	Kilning is the process of drying malted grain in a kiln using an indirect heat source to halt germination and evaporate much of the moisture from the malted grains. Kilning grain stated to become popular in the early 18th century and by the 19th century was the predominant method for drying malt. Prior to kilning, malt was often dried over open flame which would impart a smoke flavor in the finished beer, similar to what you may find today in a German rauchbier.
Krausen:	Krausen is the foamy and bubbly head that forms on top of beer during primary fermentation. As yeast ferments the sugars in a beer, it creates a great deal of CO2. The Krausen is formed as the CO2 rises to the top of the beer mixing with proteins, yeast and residues in the beer forming a tall layer of yeast saturated bubbles. Krausening is also a term for when a measured amount of actively fermenting beer and or krausen is added to a more thoroughly fermented beer as a means of conditioning or naturally carbonating the beer. Krausening is typically done as a means of carbonating a bottled beer with out violating the German beer purity laws.
Lacing or Lace:	Beer lacing is the white foam residue that is left on the side of the glass after the beer has been consumed or once the head has subsided. It is called lacing because it resembles white lace cloth. Lacing is considered a beneficial quality for a beer to have and typically speaking, a beer with a good head retention will also have good lacing.
Lager:	Lagers are beers that are fermented using a bottom fermenting yeast. Lager yeasts are slow fermenting and they ferment at low temperatures when compared to ales. Depending on the yeast strain, a lager typically conducts a primary fermentation at a temperature range between 40 F and 55 F. Lager, is the German word for storage and lagers typically have their secondary fermentation temperature reduced and may condition for several months before they are considered finished.
Lag Phase:	The lag phase is the period of time in which yeast adapts to the new fermentation environment and undergoes significant reproduction. Depending on the state of the yeast (reactivated, chilled or dried), health of the yeast cells, variety of yeast, amount of dissolved oxygen available in the wort, temperature of the wort and amount of available fermentable sugars, the lag phase may last anywhere from 2 to 24 hours. The lag phase begins as soon as the yeast is introduced into the wort and during the lag phase, very little CO2 or alcohol is produced. The shorter the lag time the better so that the desired yeast has a chance to take control of the wort before unwanted bacteria or wild yeast strains do. Ways of decreasing your lag time include creating a yeast starter or rehydrating dried yeast. Making sure that your yeast and wort are at the correct temperature when pitching your yeast and remain at an ideal temperature until the lag phase has ended, well aerating your wort so that the yeast will have enough oxygen available and pitching enough yeast for the gravity of your wort.
Lautering:	Lautering is a brewing process where hot water (typically heated to 168-170 F) is used to flush the sugars from the crushed grains after the mash has completed. Once flushed from the grains, the hot water and sugars are then transferred from the mash tun or lauter tun.
Lauter Tun:	A lauter tun is a brewing vessel used by larger scale breweries. After the mash has completed, the grains are transferred to the lauter tun where the converted sugars and be thoroughly extracted from the grains. The lauter tun has rotating arms with cutting blades that rake the mashed grains. Hot water is sprayed upon the grains to flush the sugar though a false bottom at the base of the lauter tun.
Liquid Malt Extract:	Liquid Malt extract or LME is typically used in extract beer brewing, yeast starters and in some cases all grain brewing. To make liquid malt extract, the sugars from a brewing mash are transferred from a mash tun or lauter tun and dehydrated and reduced in a vacuum chamber. When the process is completed the liquid malt extract is only 20% water. Typically no hops are added to a malt extract.
Liquor:	Liquor in beer brewing terms is simply water. The hot liquor tank is a large vessel that heats water for the different steps in the brewing process, the water that is released from the hot liquor tank is known as liquor.
Lovibond:	Lovibond is one of the methods used to measure the color of beer. Using the Lovibond method, a beers color is compared against colored glass slides to determine a numerical value for the beer. The more recently created and more precise Standard Reference Method has for the most part replaced the Lovibond method of measuring the beer color.
Malt:	Malt is germinated grains, such as barley or wheat that have been soaked, germinated and then dried in a process known as malting. The malting process is conducted by taking the grains selected for malting and then soaking them in water until they germinate. Once germination has begun, the grains are transferred to the germination floor and then dried with hot air to halt the germination process. Malt is critical for brewing because of the enzymes that are developed during the germination and malting process. These enzymes are measured as diastatic power and are what enables starches to be converted into sugars during the beers mash process. A beer with too low of a ratio of malted grains to non malted grains in its grain bill will not have enough diastatic power to be able to convert all of the starches to sugars and there for will have a very low starting gravity and as a result a low alcohol by volume.
Maltodextrin:	Maltodextrin is a mostly unfermentable carbohydrate produced by the partial hydrolysis of starch or glycogen. Maltodextrins typically impart little or no flavor upon the finished beer but are important because they can be a valuable method for adding gravity and perceived body and mouth feel to a beer. This can be extremely helpful when you are brewing a heavy adjunct beer such as a gluten free ale that might have a thin or diminished body. Maltodextrin is often made from corn and a typical composition will be .5% dextrose, 2.5% Maltose, 3.5% maltoriose, 93.5% higher saccharides. You will want to consult your vendor for actual numbers.
Mash:	The mash is water saturated crushed malts, unmalted grains and adjuncts that are present in the mash tun when the mashing occurs. During the mashing process the starches present in the mash will be converted to sugars so they can later be fermented by the yeast and converted to alcohol.
Mashing:	Mashing is the process of mixing and infusing crushed malts, unmalted grains and adjuncts with hot water from the hot liquor tank. As the grains and adjuncts mix with the hot water at specific temperatures, enzymes from the malt activate and convert the starches into sugars. At the same time that the starches are being converted to sugars, color is also being extracted from the grains which is the primary determining factor of the beers final color. The mashing process takes place in a brewing vessel called a mash tun.
Mash Bill:	A mash bill is the whole of the different malts, grains and adjuncts that make up a beer. The mash bill is very important when designing a beer recipe as it is primarily responsible for the potential original gravity, color and diastatic power of the beer.
Mash Tun:	A mash tun is a brewing tank used for converting and extracting sugars from grains and certain types of adjuncts. The crushed grains are loaded into the mash tun and then mixed with temperature controlled hot water. The hot water causes an enzyme reaction in the grains that converts their starches to sugars. The sugars are then rinsed from the grains with hot water that helps liquefy the sugars so that they can be more easily extracted from the grains. Many mash tuns are fitted with a raised perforated false bottom that permits the sugars to be extracted from the grains without having the grain husks to be transferred to the next stage of the brewing process.
Milling:	Milling is the crushing of grains and malt in preparation for the mash. The grains are milled so that the husk is cracked and that the internal starches of the malt and grains will be exposed to the enzyme reaction that will be taking place in the mash.
Mouthfeel:	Mouthfeel or the mouth feel of a beer is the mouths perception of the body of a beer and is typically described as light, medium, or full. A beers body is formed from the residual proteins, minerals, salts and unfermented sugars that remain in the finished beer. The body of a beer is perceived as viscosity or thickness by the mouth. Each style of beer has a coinciding expectation for mouthfeel and beers are rated on that expectation. For instance a lager or pilsner should have a light body and an imperial stout should have a full body if they are brewed correctly.
Noble Hops:	The term noble hops refers to either German Tettnang, German Hallertauer, German Spalt or Czech Saaz hops. These noble hop varieties are all classified as aroma hops and have a relatively balanced Alpha and Beta acid ratio which allows them to impart a subtle bitterness and full aroma. Each of these hops have a long tradition in brewing and are named after the region that they were originally cultivated in.
Original Gravity:	Original gravity or OG is the specific gravity reading of a beers wort prior to having yeast pitched for fermentation. The original gravity reading is important because it gives the brewer an idea of how much sugar is available for fermentation and what the approximate alcohol by volume will be once fermentation completes. The original gravity reading also permit a brewer to calculate his or her brew house efficiency to determine what percentage of starches and sugars were extracted from the grain bill used to make the beer. Typically either a hydrometer or refractometer are used to take the original gravity reading.
Oxidation:	Oxidation is the degradation or modification of beer when it comes in contact with oxygen or an oxidizing agent. Oxidization in beer is inevitable and is occurring in beer at all times regardless of how it is stored. That being said, there are ways to diminish the rate of beer oxidation. A good rule of thumb is to prevent oxygen from coming in contact with your beer whenever possible. The only time that oxygen should intentionally be introduced to a beer is when aerating or oxygenating wort prior to pitching yeast and in rare cases to facilitate a souring process. Great caution should be taken when transferring, racking, kegging and bottling beer to avoid splashing it or exposing it to more oxygen then is necessary. When possible, fermentation vessels, kegs and bottles should be purged with CO2 prior to and after having beer transferred. Heat is another factor that impacts oxidation and whenever possible beer should be stored cold to reduce oxidation rates and to preserve its freshness. Another way to help slow the impact of oxidation is to keep bottles and fermenters shielded from sun light. Beer that has been oxidized typically has a stale or paper like taste. In darker beers you may also smell or taste sherry notes.
pH:	pH, short for potential Hydrogen measures the acidity or basicity of a brewing fluid such as the starting water (liquor), mash, wort or beer. A fluid with a pH less than 7 is acidic and a fluid with a pH greater than 7 is basic or alkaline. If a fluid has a pH of 7, such as pure water, then it is considered neutral. pH is a very important factor in all grain brewing and different geographical areas and water sources can have dramatically different pH levels and mineral contents that impacts the pH of a mash. Additionally the style of beer that you brew will have a significant impact on your mash pH level. Typically the darker the color of the malts that comprise your grain bill, the more acidic your mash will be. This is important because the enzymatic conversion of starches to sugars only effectively occurs in a mash that has a pH between 5.0 – 6.0; ideally your mash would be between 5.2-5.5 pH which is considered optimal. A great starting place for dialing in your mash pH is to get a copy of your municipal water report to learn about the pH and mineral composition of your brewing water. Software such as BeerSmith has great tools built in that will help you determine when brewing salt and mineral additions are required to help you bring your pH in line when comparing your local water to that of a specific style of beer. Lastly, purchasing some inexpensive pH testing strips is a great way to make sure that your mash pH is at an appropriate level.
Protein Rest:	A Protein Rest is a period of enzyme activity during mashing when excess protein is removed and digested. It is typically part of a series of temperature holds arranged in a sequence to ensure progressive digestion of beta-glucans, proteins, and starches. Not all mashes require a protein rest, but if poorly modified malt or high protein adjuncts are used, excess protein is likely to be released into the wort, leading to possible hazes in finished beer. Removing protein from wort involves both precipitation and enzyme digestion. A temperature of 119oF (43oC) is optimal for these and results in the removal of intact proteins in a precipitate and their breakdown into polypeptides and amino acids. This digestion is most effectively achieved using natural protease enzymes derived from the barley malt. Whereas the endo-proteinases act best at relatively low temperatures of around 119oF (43oC), the exo-peptidases (notably carboxypeptidase) are much more heat tolerant and are able to act at the higher temperatures used for saccharification. It is the endo-peptidases whose survival would be facilitated at the lower temperatures, but there is a school of thought that says these enzymes cannot act because they are blocked by endogenous inhibitors from the grist. Accordingly it has been suggested that the term “protein rest” is a misnomer and that it should be called a “beta-glucan rest” because it is the breakdown of beta-glucans by heat-sensitive beta-glucanases that is much more relevant at these lower temperatures. Many brewers seek a middle ground between the optimum temperatures for peptidase and proteinase activity, settling on a rest temperature of 122oF (50oC), with the typical stand lasting from 10 to 20 minutes.
Phenols:	Beer phenols are chemical compounds similar in structure to alcohols that are generated by yeast during fermentation. In certain styles of beer, such as Bavarian hefeweizens and wit beers, phenol flavors such as bubble gum, banana and clove are considered desirable; but in other styles they are considered to be an off flavor or flaw. Causes of unwanted phenols include wild yeast or bacteria, chlorine and excess sanitizer.
Pitching:	Pitching or yeast pitching is the term used for when a brewer adds yeast to the cooled wort to begin the fermentation process. Yeast should be pitched to the wort as quickly as possible to diminish the possibility of wild yeast strains or bacteria taking control of the sweet wort before your selected yeast has the opportunity to. Additionally, your pitched yeast should be as close to the same temperature as the wort that you are adding it to in order to avoid shocking the yeast and to help the yeast acclimate as quickly as possible and lower yeast lag time. It is critical that your wort is in an appropriate temperature range for the yeast to be able to survive and thrive; for most ales that temperature range is between 65 and 80 F for pitching but you should always consult your yeasts packing for the specific temperature range of the variety you are using.
Primary Fermentation:	Primary fermentation in beer brewing is the initial fermentation process where yeast will convert most or all of the wort sugars to alcohol and CO2 (carbon dioxide). After the yeast has been pitched into the wort, there is typically between 2 and 24 hour yeast lag time where the yeast acclimates to the fermentation environment and begins to replicate consuming sugars and the available oxygen in the wort; there is little alcohol conversion and CO2 generated during the lag phase. Once the lag phase completes, a foamy head called a krausen begins to form in the fermentation vessel. The krausen is composed mostly of proteins, yeast and the carbon dioxide that the yeast is rapidly producing. During primary fermentation the yeast is producing approximately equal parts of both alcohol and CO2. Depending on the style of beer, original gravity, quantity of yeast pitched and fermentation temperature, the primary fermentation for an ale with typically lasts between 5 – 14 days where it will then be transferred to a secondary fermentation vessel to allow the beer to condition and finish out its fermentation. In some cases only a primary fermentation is completed and the beer may spending additional time in the primary fermenter or condition in the bottle, keg or holding vessel.
Priming:	Priming a beer is the process of adding sugar during the bottling process in order to carbonate the beer. You can bottle condition and carbonate your beer by priming it at the time of bottling with a specific amount of sugar. Using approximately .5 tea spoons ( 1/2 tsp) of priming sugar per 12oz bottle will typically provide adequate carbonation for most beer styles. Typically you will want to prime your beer with Corn sugar (dextrose). It is critical that your beer completes its fermentation prior to priming and bottling, as if there are residual fermentable sugars available it may create too high of pressure in the bottles and cause them to explode. It is also critical that the yeast is still viable so that the priming sugar is converted to CO2 in the bottle and you do not end up with a flat and overly sweet beer. As will all aspects of brewing, cleaning and sanitation is always paramount. Always make sure that your bottles and caps are clean and sanitized prior to bottling.
Racking:	Racking is the process of transferring beer from one brewing vessel to another. Beer is typically racked utilizing a racking arm, racking cane or racking tube. The beer is either pumped from one vessel to another or a siphon or CO2 tank is used to create a positive or negative pressure and gravity is used to rack the beer.
Recirculation:	Recirculation is the process of pulling the wort from the base of the mash tun or lauter tun and recirculating it back on to the top of the grain bed. Recirculation typically occurs after the end of the mashing process. As the hot wort is recirculated through the grain bed of the mash, the grains act as a particle filter clearing the wort. As the wort is recirculating it becomes cleaner and less turbid until finally it is clear and ready to be passed to the boiling vessel. A pump is typically used to recirculate the wort at a steady and controlled pace. In the case where a home brewer does not have a pump available, the wort may be drawn into a container and slowly poured back on top of the grain bed. The process can be repeated until the wort has become clear. Additionally, rice hulls may be added to a mash as a means of boosting the filtration capability of the grain bed.
Reinheitsgebot:	The Reinheitsgebot, also known as the German Beer Purity Law was originally drafted in 1487 and put into law on April 23rd, 1516 in the city of Ingolstadt, in Bavaria, Germany. The original Reinheitsgebot document stated that the only ingredients that could be used in the production of Bavarian beer were water, barley and hops. In addition to ingredient restrictions, the documents also set pricing standards for the sale of beer. At the time the Reinheitsgebot was drafted, the function of yeast in brewing was not understood and for that reason it was not listed as an acceptable ingredient in beer.
Resin:	Hop resin is a sticky compound formed in the lupulin glands of the female hop flower. The resins of the hop flower are composed of alpha and beta acids and are chiefly responsible for the bitterness and hop aroma found in beer. Additionally, Alpha acids found in the hop resins function as a mild antibiotic and work as a preservative in beer.
RIMS or Recirculating Infusion Mash System:	RIMS or Recirculating Infusion Mash System is a mash infusion system that either utilizes a pump to recirculate the fluid in the mash over a secondary heat source (outside of the mash tun) to maintain the mash temperature or constantly recirculates the mash onto itself while direct heat is applied to the mash tun to regulate temperature. The fluid is pumped at a rapid enough pace to keep the temperature of the mash at an equilibrium and prevents the wort from being scorched or over heated.
Saccharification:	Saccharification in very basic terms is the conversion of starches to sugars. When it comes to all grain brewing, saccharification is a critical conversion process that occurs during the mashing process. As the mash tuns temperature is increased to a range of 120 F to 158 F, the diastatic enzymes of the malted grains begin to activate and break the starches of the grains and adjuncts into sugars. The alpha amylase enzymes break apart complex starches into sugars that the beta amylase enzymes break apart sugars even further into easy to ferment maltose sugar. Precision is critical when it comes to the temperature of a mash and 10 degrees makes a massive difference. The beta amylase is more temperature dependent than alpha amylase, and when the temperature in the mash begins to rise above 158 F, the beta amylase is no longer capable of breaking apart the more complex sugar chains into maltose. So if your target mash temp is 152 F and you instead conduct your mash at 162 F, you will be left with a massive amount of unfermentable sugars in your finished beer and it will have a fuller body and overly sweet finish. Beta amylase thrives in a temperature range of 140 F -150 F, so if your target mash temp was 152 F and you instead conduct your mash at 142 F, you would end up with a beer with a very thin body and dry finish due to a deficiency of unfermentable sugars. This is the reason why the typical mash saccharification rest temperature is in a range of 152 F to 154 F; it provides a good temperature compromise for both alpha amylase and beta amylase to carry out their required starch and sugar conversion processes.
Secondary Fermentation:	Secondary fermentation is the process of transferring your beer to a secondary fermentation vessel to allow the beer to complete its fermentation cycle and condition in a clean environment. The primary reason for a secondary fermentation is to improve the taste of a beer. Towards the end of the primary fermentation much of the yeast, beer solids and hop solids will fall out of the beer and form sediment on the bottom of the fermenter. If left in contact with the beer too long, the dead yeast and solids and impart off or undesirable flavors upon the beer. For this reason, many brewers choose to rack the beer off of the sediment into a secondary fermenter to allow the beer to finish out fermentation, clarify and condition. The need for secondary fermentation is somewhat dependent on the style and characteristics of the beer that you are creating. For instance, if I am brewing an American wheat hefeweizen, I probably will not go through the trouble of a secondary fermentation because it is a relatively low alcohol beer with a low flocculating strain of yeast. This means it will ferment quickly, so the beer is only in contact with the sediment for a short period of time and much of the yeast will remain in suspension with this style of beer to a yeasty taste and cloudy appearance is appropriate for that beer. If I was brewing an IPA with a high starting gravity and I wanted to highlight the hoppy flavor of the beer, I would certainly conduct a secondary fermentation to remove as much yeast and yeast flavor from the finished beer to help both with taste and clarity. Depending on the beer style, gravity, fermentation temperate, yeast strain and yeast health, a secondary fermentation can typically last anywhere from 2 weeks to several months. When conducting a secondary fermentation on certain beers such as a sour, the secondary fermentation can in some cases last over a year to complete.
Sediment:	Beer sediment is the collection of solids that fall out suspension of a fermenting or conditioning beer. Sediment is mostly comprised of yeast, grain solids, hop solids and adjunct solids. As the beer ferments or conditions, the dense solids fall out of the beer and settle to the floor of a fermenter, conditioning vessel, or bottle in the case of a bottle conditioned beer. The sediment is typically discarded but if the yeast is still healthy it may be recycled from the sediment to be used to ferment future beers.
Session Beer:	A session beer is defined as a beer with an alcohol by volume or ABV of less than 5%. The purpose of a session beer is to permit the drinker to enjoy multiple beers at a sitting with out becoming overly intoxicated.
Sparge Arm:	A sparge arm is a piece of brewing hardware used to flush the grain bed with hot water in order to extract any residual sugars left behind in the mash. The sparge arm water needs to be in the range of 168 F in order to liquefy the remaining sugars; if the temperature exceeds 170 F, the brewer many risk pulling excess tannins from the grain husks and causing off flavors and chill haze in the finished beer. Sparge arms are typically constructed of copper, stainless steel or plastic and should have some form of flow control so that the approximate flow rate can be set to keep pace with the flow over wort leaving the mash tun or lauter tun and heading to the boil kettle.
Sparging:	Sparging is a beer brewing process that involves passing heated water through the grain bed of a mash to extract sugars from the crushed grains and adjuncts. Sparging is typically conducted at approximately 167 F – 170 F; if the temperature exceeds 170F the brewer risks extracting excessive amounts of tannins from the grains and if the temperature is too low than the sparge will be ineffective at liquefying the remaining converted sugars from the grains. While sparge water is being passes from the hot liquor tank to the mash tun or lauter tun via a sparge arm, the extracted sugars and water are being drained from the base of the vessel and relocated to the boil kettle in preparation for to upcoming boil.
Specific Gravity:	In brewing, specific gravity is defined as the ratio of the density of a brewing liquid such as wort or beer as compared to the density of pure water. Typically either a hydrometer or a refractometer is used to determine the specific gravity of beer or wort.
Standard Reference Method or SRM:	Standard Reference Method or SRM is a method of measurement used to determine and define a beers color on a numeric scale using a photometer or spectrophotometer . The color of a beer is an important factor when judging a beers overall quality. Different beer styles are expected to fall into a specific color range and the SRM is a way of measuring that. The lighter the color of a beer, the lower the corresponding SRM value will be and as expected, the darker the beer the higher the SRM value will be. Beers range anywhere from 2 to in excess of 40 on the SRM scale. Below is a chart featuring the SRM value on the left, with the approximate color and beer style example to the right.
Step Infusion:	Step infusion is a beer mashing method where differing temperatures and quantities of water are infused in the mash tun from the hot liquor tank at specific intervals or steps in the mash process to control sugar conversion and extraction.
Tannins:	Tannins are organic compounds found in the husks grains. Excessive tannins are almost always considered to be a flaw in beers and are interpreted as a harsh astringent bitterness or a mouth drying sensation. Excessive tannins are typically caused by too high of a mash pH or excessive temperatures during mash out or sparging. Tannin extraction is dramatically increased when mashing or sparge water temperatures exceed 170 F. Please also note that as the lautering and sparge process comes to a conclusion, the pH of a mash is increasing compounding the potential for tannin extraction. In addition to the off flavors created by tannins they can also be significant contributors to chill haze in a beer. Hops also release tannins into beer, but the hop tannins are not considered to be significant contributors off flavors or chill haze. Ways of removing excess tannins from beer including cold crashing or cold conditioning the beer at approximately 34 F for 2 or more weeks. That should cause some of the excess tannins and proteins to precipitate out of the beer onto the bottom of the fermenter or conditioning vessel. You may also use a beer a beer fining agent such as gelatin or isinglass to help clear the tannins.
Top Fermentation:	Top fermentation of top fermenting describes the tendency of ale yeast cells to conduct the majority of fermentation on the surface of the fermentation vessel as opposed to the bottom as is common with lager yeast. Top fermenting ale yeast is typically fermented at a temperature range between 65 F and 75 F; the lower the temperature the slower the fermentation is carried out. Excessive fermentation temperatures have been known to generate off flavors in beer and that is why a temperature range of 65 F to 75 F is typically recommended. When a top fermenting ale is most active, a thick head of foam known as a krausen forms on the top of the fermentation vessel and will subside as the fermentation draws to an end. The length of fermentation is dependent of the health of the yeast, the original gravity of the wort, the temperature of the fermentation and the amount of yeast pitched but typically takes anywhere from 1 week to 3 week time for the majority of fermentation activity to complete. A secondary fermentation is often times conducted so that any remaining fermentable sugars can be converted to alcohol and so that the beer can condition and allow the yeast to precipitate to the bottom of the fermenter in preparation for bottling or kegging.
Trub:	Trub or hot trub is the excess material left in the boil kettle after the wort has been transferred. Boil kettle trub typically consists of hop matter, grain fiber, tannins and the dense proteins known as the hot break that combine during the first 15 minutes of the boil and ultimately drop to the bottom of the kettle. It is recommended that the trub not be transferred to the fermenter as it may impart off flavors on the finished beer.
Turbidity:	Turbidity is the haziness or cloudiness of a beer or wort and is caused by the suspension of particulate matter in the fluid. In order to remove the turbidity of wort in the mash or lauter tun, it is recommended that you recirculate the wort over the grain bed which will act as a particle filter. Recirculation is a great method of clearing the wort prior to sending it to the boil kettle.
Vorlauf:	Vorlauf is the German word used for mash recirculation. Vorlauf is the process of pulling the wort from the base of the mash tun or lauter tun and recirculating it back on to the top of the grain bed. Vorlauf typically occurs after the end of the mashing process. As the hot wort is recirculated through the grain bed of the mash, the grains act as a particle filter clearing the wort. As the wort is recirculating it becomes cleaner and less turbid until finally it is clear and ready to be passed to the boiling vessel. A pump is typically used to recirculate the wort at a steady and controlled pace. In the case where a home brewer does not have a pump available, the wort may be drawn into a container and slowly poured back on top of the grain bed. The process can be repeated until the wort has become clear. Additionally, rice hulls may be added to a mash as a means of boosting the filtration capability of the grain bed.
Wet Hopping:	Wet hopping is when freshly picked \ undried hops are added to a beer at some point of the brewing, fermentation or conditioning process. These hops are typically added to the beer within a day or two of being picked to maximize the unique flavors extracted from a freshly picked hop. A fresh or wet hop is typically less predictable than a dried hop and will usually impart lower amount of bitterness than the same weight dry hop due to the additional moisture weight in the wet hop.
Whirlpooling:	Whirlpooling is the process of separating the trub from the wort by utilizing centrifugal force to confine the trub to the center of the kettle so the wort can be drawn off without disturbing the trub cone. Whirlpooling can be achieved by quickly moving wort in a clockwise or counter clockwise motion until a vortex begins to form in the center of the kettle. Once the vortex has formed, the trub will begin collecting and settling into the center of the kettle and forming a cone as the spinning wort forces the denser particulates towards the center. It is important to allow 15 to 20 minutes for the cone to form before drawing the wort from the kettle. If you are using an immersion chiller, you would want to chill the wort prior to whirlpooling and then draw the wort out slowly as not to disturb to trub cone.
Wort:	Wort is the name given to the sugar rich liquid that is extracted from the mash, prior to fermentation. Prior to the boil when the hops have not yet bittered the wort, it is known as sweet wort. After the boil but prior to fermentation it is known as bitter wort since the beta acids from the hops have imparted a bitter flavor upon it.
Wort Chiller:	A wort chiller is a device used to rapidly cool the wort after the boil has completed. Typically the wort is knocked down from boiling temperatures to less than 80 F as quickly as possible so that yeast can be pitched. Once the wort falls below boiling temperatures it becomes susceptible to bacterial and wild yeast contamination. It is important to get the wort below 80 F without splashing or aerating it too much as hot side aeration can oxidize your wort above that temperature. There are three typical types of home brewing wort chillers. Immersion chillers, are large coils constructed of copper or stainless steel and are placed inside the brew kettle while cold water is pumped through the chiller, cooling the wort. Plate chillers are made of fused plates and have channels where the cold water being pumped though one end, intersects with the plates being heated by the wort from the other end, rapidly cooling the wort. Lastly, counter flow convolution chillers have hot wort flowing through one tube as chilled water passes over it from the opposite direction in a surrounding tube. I personally prefer the counter flow convolution chillers as the permit me to cool my wort quickly while also being easy to clean, since hops and trub are less likely to get lodged in the tube then they are in a plate chiller.
Yeast:	Brewing yeast strains are unicellular funguses that convert simple sugars into approximately equal parts of alcohol and carbon dioxide during the fermentation process. There are two main types of beer yeast varieties, saccharomyces cerevisiae which is a top fermenting ale yeast and saccharomyces pastorianusis a bottom fermenting lager yeast.