ABV (alcohol by volume) A standardized measure of how many milliliters of ethyl alcohol are present in each 100 ml of an alcoholic beverage when measured at 68ºF.
Adjunct Any unmalted grain, sugar, or syrup used in the brewing process, including rice and corn. Adjuncts are often used to lighten the body of beer and/or increase its alcohol content.
Ale A malt- or wheat-based, alcoholic beverage fermented at warm temperatures by a top-fermenting strain of yeast. Examples of ales include stouts, porters, and bitters.
All-grain brewing A brewing style using only grains, for example, malted barley and wheat, rather than malt extract.
Alpha acids Compounds found in the flower of the female hop plant which are the primary source of bitterness in beer.
Aroma hop A late-addition hop added to wort at the end of the boil in order to impart primarily aroma, rather than bitterness. A variety of hop recognized for its aromatic character.
Attenuation The percentage of sugars in the wort which have been converted to alcohol in the final beer. A well-attenuated beer will have a drier character, while a less-attenuated beer may have a distinct sweet quality.
Autolysis Degradation of dead or dying yeast cells by the yeast’s own enzymes if left too long on the lees or yeast cake. Autolyzation often produces an unpleasant meaty quality in beer.
Autosiphon A simple device that automatically starts and stops a siphon based on liquid levels.
Barley A cereal grain; the most commonly used brewing grain and the primary ingredient in craft beer.
Barrel A unit of liquid measurement equal to 31 gallons.
Base malt Usually a pale malt, which makes up most of the recipe.
Batch The amount of beer one is brewing, for example, 5 gallons is a common size for a batch of home-brewed beer.
Beer style A term used to organize ales and lagers into different categories or families, based on a number of factors and characteristics, including color, flavor, production method, and origins.
Germinating boxes at a malting facility.
Beta-amylase The enzyme responsible for the conversion of starches to sugars.
Bittering hop The first addition of hops, usually at the start of the boil; varieties of hops that impart more bitterness than aroma.
Bitterness A sharp, acrid flavor characteristic of beers; largely a result of adding hops to the wort. The degree of bitterness varies depending on the variety and amount of hops added to the beer. Tradition dictates that various styles of beer will have different bitterness profiles. Tannins may also impart an astringent bitterness.
Body Also called mouthfeel; how the beer feels in your mouth – thin-, medium-, or full-bodied.
Bottle conditioning The process of naturally carbonating beer in the bottle by employing refermentation.
Bottling tip A manual bottle-filling device that, when depressed, allows beer to flow freely, filling the bottle to the correct level.
Brewhouse Usually refers to the vessels used in the brewing of beer and/or the area they are in.
Brewing salts Minerals, such as calcium sulfate or gypsum, added to brewing water to increase its hardness.
Brewpot The vessel in which a home brewer boils the wort. Also referred to as the “brew kettle” or simply “kettle”.
Brewpub An establishment that brews its own beer and also serves food.
Bright The clear, finished beer. The result of either filtration or a natural settling process, often in conjunction with a clarification or fining aid.
Carbonation The effervescent quality of beer, due to the presence of carbon dioxide (CO2), a gas.
Carboy A glass (or plastic) jug with a narrow mouth, usually 5 or 6 gallons in size, often used by home brewers as a fermentation vessel.
CO2 (carbon dioxide) A colorless, odorless gas; a by-product of fermentation.
Contamination The presence of an unwanted and undesirable, impure element or ingredient. In beer, contamination most often results in unpleasant, off-flavors.
Conversion The enzymatic breakdown of starches into simple sugars which takes place in the mash tun during the mash rest.
Cornelius keg A 5-gallon soda keg often used by home brewers for packaging and serving their home-brewed beer.
Craft beer Beer that is traditionally brewed by small, independent brewers.
Craft-beer enthusiast One with a passion for seeking out and drinking craft beers.
Decoction mash A brewing technique in which approximately one-third of the mash is removed, boiled, and returned to the mash tun, resulting in a fuller, maltier beer typical of German styles.
Dextrins A group of light carbohydrates produced by the degradation by water of starch or glycogen. In beer, dextrins contribute body, or mouthfeel.
Diastatic enzymes The catalysts responsible for breaking down and converting the starch in malt to sugars, upon which the yeast can feed.
Doughing in The process of mixing grain with hot water, thus creating the mash. Also called “graining in” or “mashing in”.
Dry hopping Adding a quantity of hops to beer post-fermentation. Dry hopping imparts primarily flavor and aroma, less so increased bitterness.
Ethyl alcohol A colorless, volatile liquid with an intoxicating quality, which is found in wine, beer, and spirits. Ethanol is the chemical name for ethyl alcohol.
Extract brewing A form of brewing which uses the already extracted malt sugars, therefore making the mash step unnecessary.
Fermentation In beer making, the process during which yeast breaks down sugars in the wort and converts them to ethyl alcohol. CO2 is another by-product of fermentation.
Fermentation lock A device that allows fermenting beer to release carbon dioxide, without allowing air to enter the fermenter.
Final gravity The specific gravity of beer after fermentation is complete.
Fining agents, finings A substance, often seaweed- or gelatin-based, that when added to wort or beer binds to and precipitates out suspended compounds such as yeast, proteins, and polyphenols, leaving the finished beer clear or “bright.”
Flat Undercarbonated or uncarbonated.
Flavor profile A comprehensive sensory impression which includes body, aroma, bitterness or sweetness, aftertaste, and off-flavors.
Flour Finely milled grain.
Forced carbonation Artificially carbonating a beer by injecting CO2 directly into the cold liquid.
Friable Easily crushed.
Grain In brewing, most often used to mean malted barley or wheat. Often used interchangeably with malt.
Grain bill The amount of malt or grain, including specialty malts, in a specific recipe.
Graining in The process of mixing grain with hot water, thus creating the mash. Also referred to as “mashing in” or “doughing in.”
Growler A reusable glass jug, often 1 half-gallon in size, used for transporting beer “to-go”.
Head retention The ability of a beer to form and hold surface foam.
Headspace The void between the top surface of the liquid and the container or vessel.
Home brewer An amateur brewer or hobbyist who brews beer at home.
Hop The female flower, or cone, of the hop plant, a climbing vine. Used to impart aroma, bitterness, and stability in beer.
Freshly harvested hop cones.
Hops can be grown in most parts of the country, including your own yard.
Hoppy Having the aroma or taste of an abundance of hops. An enhanced bitterness.
Humulus lupulus Commonly, hops; a species of climbing, flowering plant in the Cannabaceae family.
Hydrometer An instrument used for measuring the density (specific gravity) of liquids.
Iodine test Using a drop of iodine to determine whether conversion of starches to sugars has taken place in the mash. Iodine will turn black in the presence of starch.
Brewery tanks were not always made of stainless steel. Dick Yuengling Sr. poses with a wooden “at rest” tank.
Irish moss Also carrageen; a species of red algae used as a fining agent in the kettle.
Kettle The vessel in which wort is boiled.
Kilning Baking, burning, or drying in an oven or furnace (kiln) capable of very high temperatures. The final stage in the malting process.
Knockout The post-boil transfer of wort through a heat exchanger from the kettle to a fermentation vessel.
Lager A malt-based alcoholic beverage fermented and matured for long periods of time at cooler temperatures by a bottom-fermenting strain of yeast. Examples of lagers include Pilsners, Bocks, and Märzens.
Lauter In brewing, the process of separating the clear, sweet liquid wort from the mash and residual grains.
Lauter tun The vessel traditionally used for the separation of the wort and mash. Also “mash tun”.
Lees The layer of sediment at the bottom of the kettle or fermenter. Also known as “trub”.
Lovibond Scale A standard for measuring color and represented in degrees.
Lupulin The yellow, powdery substance found in the flower (cone) of the female hop plant.
Maillard reaction The reaction between amino acids and sugars that enhances the flavors of browned foods. It also occurs in kilning, as malts are darkened through the kilning process.
Malt, malted barley A cereal grain that has been steeped, germinated, and dried, rendering it suitable for brewing.
Malty Used to describe a beer with a medium- to full-body and sweet, bready flavor.
Mash The uniform mixture of crushed grain and warm water, which will yield the sweet wort for brewing.
Mash rest The time in which the conversion of starches to sugars occurs in the mash.
Mash tun The vessel in which the mash is prepared. Also “lauter tun.”
Microbrewery A small commercial brewery that produces beer in limited quantities, often with only local distribution.
Milling The process of crushing barley or wheat by means of a mill to expose the starches in preparation of brewing.
Mouthfeel The way a substance, such as beer, feels in the mouth. Also “body”.
Nanobrewery A very small commercial brewery, generally one producing beer in batches of 3 barrels (93 gallons) or less.
Noble hop One of four varieties of European hops valued for their aromatic qualities, rather than their bitterness.
Nose Aroma, smell.
Off-flavors Strange or undesirable tastes that are not part of a standard flavor profile. Often the result of contamination due to poor sanitation, too warm temperatures, or improper procedures.
Original gravity The specific gravity of wort prior to the onset of fermentation.
Oxidation A stale, papery, or sherry-like quality present in beer. Aeration of hot wort is one common cause.
Partial mash A brewing method that combines both malt extract and grain.
Pitching The act of adding yeast to a fermenter immediately after knockout.
Primary fermentation The first, most active stage of fermentation, generally lasting about three to five days.
Proteins Nitrogenous organic compounds consisting of large, complex molecules made up of a chain or multiple chains of amino acids.
Proteolytic enzymes The catalysts responsible for breaking down long complex chains of protein molecules into simpler proteins and amino acids.
Racking In brewing, the transfer of wort or beer from one vessel or container to another.
Refractometer A device used to measure the density of a liquid using a refractive index. In brewing, a refractometer is used to measure the sugar content of wort.
Reinheitsgebot The German Beer Purity Law of 1516, which decreed that beer could only be brewed with three ingredients: barley, hops, and water.
Rolling boil A full, vigorous boil.
Saccharification The process of breaking down complex carbohydrates, such as starch, into simple sugars.
Saccharomyces cerevisiae The species of yeast used for baking, brewing, and wine making. Literally, “sugar fungus.”
Sanitation Measures taken to keep areas, surfaces, and equipment free from dirt and contaminants.
Secondary fermentation The aging or maturation stage of the fermentation process after the initial fermentation is complete. Beer is transferred to a second vessel, leaving behind most of the residual yeast.
Single-infusion mash The simplest mash technique, in which grain is mixed with hot water and allowed to rest at a consistent temperature until conversion or saccharification has taken place.
Siphon A tube or device used to convey liquids from one vessel or container to another by means of suction or immersion.
Sparge, sparging A gentle, controlled rinsing of the mash bed with warm water to extract the sweet, sugary liquid or wort.
Specialty malt Any malt other than a standard base malt used in brewing. Smaller quantities of specialty malts are used to impart flavor, aroma, and color in a wide variety of beer styles.
Specific gravity The ratio of the density of a substance, relative to the density of a standard, such as water in the case of a liquid.
Starches Complex carbohydrates.
Steep To soak a dry ingredient (tea or grain, for example) in liquid long enough to allow the liquid to take on the color and flavor of the ingredient.
Step mash A mash technique in which the temperature of the mash is progressively increased and held “at rest” for a specific period of time.
Sterilization To clean and completely eliminate germs and bacteria by means of chemicals or extreme heat.
Sugars Sweet, short-chain carbohydrates.
Tannins Polyphenols produced by plants that impart a bitter, astringent taste.
Trub The layer of sediment at the bottom of the kettle or fermenter. Also known as “lees.”
Tun A measure of liquid volume. A large vessel or cask.
Volatiles Undesirable compounds or substances that evaporate rapidly and are driven off easily in the form of vapor during the boil.
Volstead Act (Prohibition) The Eighteenth Amendment to the US Constitution which made producing, selling, and transporting “intoxicating beverages” illegal. Prohibition lasted from 1920 through 1933, when it was repealed by the Twenty-first Amendment.
Vorlauf The process of clarifying the wort after the mash rest through recirculation. From the German, to run (ahead).
Whirlpool A rapid, swirling volume of liquid which creates a vortex capable of drawing objects or particles into its center and down.
Wort The sweet liquid that results from combining grain with hot water in the mash.
Wort chiller A device, used during the knockout, which quickly cools boiling wort, lowering the temperature to one suitable for pitching yeast. Home-brew chillers most often use cold water, while commercial chillers may use water or propylene glycol, a food-grade coolant.
Yeast A microscopic, single-celled fungus which reproduces by budding or fission. A common variety, Saccharomyces cerevisiae, is capable of converting sugars to alcohol and carbon dioxide.
Yeast cake The yeast residue, or slurry, found at the bottom of a fermenter after fermentation.
Yeast strain A yeast specific to a particular beer style, such as American ale or German wheat beer.