Adjunct: Any grain other than malted barley used as a starch source or for flavoring properties.
Airlock: Device that fits into a vessel’s lid and that is filled with water or other liquids, enabling expanding gas inside a fermenter to escape without allowing outside air into the vessel.
Aerate: To dissolve air in a liquid.
Alpha Acid: Resin from hops that provides bitterness in beer.
Aluminum: Lightweight metal sometimes used for brew kettles or other vessels.
Autoclave: A pressurized, steam-heated vessel or chamber used for sterilization of equipment or material.
Boiling: The step in brewing at which the dilute solution of sugars and water is concentrated and hops are added.
Brewing: Craft and science of making beer.
Bright Beer Tanks: Storage tanks for clear, finished beer.
Carbon Filter: Filter used to remove chlorine from water.
Carbonate: To inject or dissolve carbon dioxide gas into beer.
Carboy: A large glass bottle (usually 5 or more gallons) in which beer can be fermented.
Caustic: Corrosive chemical.
Channeling: Tendency of liquid draining through a grain bed to carve a single path and then follow it without permeating the grain bed.
Chiller: Piece of equipment that cools hot wort rapidly before pitching yeast. See also Heat Exchanger.
Chlorine: Element used in dilute form as a sanitizing agent. Commonly present in municipal water sources, where it is used to kill bacteria.
Closed Fermentation: Fermentation process conducted in a sealed vessel with airlocks or other pressure-relief devices.
Conditioning: Process of carbonating a beer.
Conversion: The saccharification, or breakdown, of starches to fermentable sugars.
Copper: Material traditionally used in brewing equipment fabrication. Also a necessary yeast nutrient, but one that can kill yeast at excessive levels.
Counterflow: Method of heat exchange by which two liquids of different temperatures flow in opposite directions along a path separated by conductive material.
Crash: Process of milling grain. The quality (granularity and husk integrity) of milled grain.
Cylindroconicol: Describes the shape of fermenters in most commercial breweries; a cylinder capped at one end by a cone.
Decoction: Mashing method that involves removing part of the mash, boiling it, and returning it to the main mashing vessel.
Degree of Extract: Measure of mash yield or efficiency: the specific gravity of one gallon of wort made from one pound of malt.
Diatomaceous Earth: Sandy, silicate substance made up of skeletons of minute colonies of algae, called “diatoms.” Used as a filtering medium and available in different grades.
Distillation: Purification of liquid by boiling and condensing. When used to purify brewing water, will remove all ions.
Endosperm: Starchy center matter of a barleycorn.
Enzyme: Complex protein that acts as a catalyst to break starches, sugars, or other complex molecules into simpler components.
Extract: Sugars derived from grain in a mashing process. Commonly used to refer to a commercially prepared syrup or powder of such sugars.
Fermentation: Process in which yeast obtains energy in the absence of oxygen by breaking down sugar into carbon dioxide and alcohol.
Fermenter: Vessel or tank in which the fermentation process takes place.
Filter: Porous membrane or layer through which liquid is pumped, removing impurities or sediment.
Finings: Additives used to clarify a beer.
Glycol: An anti-freeze used in fermenter jackets and some heat exchangers.
Grist: The crushed malts and adjuncts that are mixed with hot water to form the mash.
Heat Exchanger: Piece of brewing equipment used to heat or cool the wort or beer.
Hopback: A chamber in the middle of the siphon line that contains fresh hops and through which the brewer runs the hot wort.
Hops: The flowers (or cones) of the female hop plant, used in brewing to impart bitter flavors to the beer, balancing the sweet malt.
Hot Break: Flocculation of protein and other matter during the boil.
Hydrometer: Measuring device used to determine the amount of dissolved sugar and other solid matter in a solution.
Infusion: Mashing method in which grain is mixed with hot water.
Iodophor: A dilute solution of iodine and phosphoric acid used as a sanitizing agent.
Ion: An atom or bound group of atoms that carries an electrical charge.
Iron: Ion that causes haze and hampers yeast.
Isomerize: To alter the arrangement, but not the kind or number, of atoms in a compound by heating or other means. In brewing, hop alpha acids are isomerized in the boil.
Jockey Box: Cooler with beer taps attached to the outside. Beer runs through cooling tubes or a cold plate inside the cooler.
Keg: Vessel used for storing and dispensing finished beer. Homebrewers typically use small soda kegs of about 5 gallons. U.S. commercial breweries typically use half-barrel kegs of 15.5 gallons. Common keg sizes will vary in other countries.
Kettle: Large vessel, usually made of stainless steel or copper, in which the wort is boiled.
Kiln: Large furnace with a perforated floor heated by either fire or heaters, in which malt is dried and roasted.
Knurl: Cut edges, grooves, or patterns used to roughen a smooth surface, thereby providing friction.
Kraeusen: (1) The large head of foam that forms on the surface of the wort during the early stages of fermentation. (2) Method of carbonation in which unfermented beer is added to finished beer to bring about a second fermentation.
Lager: To age beer at low temperatures for a period of weeks or months.
Lauter Tun: Large vessel with perforated false bottom used to strain the sweet liquid from grain after mashing.
Lead: Toxic metal occasionally found in some alloys and sometimes present as an ion in water.
Malt: Barley or other grain that is allowed to germinate, developing enzymes and sugars needed for brewing.
Malting: Process of soaking, sprouting, drying, and roasting barley to render it suitable for brewing.
Mash: The process of mixing crushed grains with hot water to convert starch to sugar. Also, the mixture of water and grain.
Mill: (1) Device used to crush grain. (2) Process of crushing whole grains. Process of crushing whole grains
Open Fermentation: Fermentation process conducted in a non-sealed vessel, often in shallow vats, open to the air.
Oxidation: Any chemical reaction in which oxygen reacts with another substance.
pH: Potential hydrogen. A measure of alkalinity or acidity where 7 is neutral, lower numbers are acid, and higher numbers are alkaline.
Pitch: To add yeast to a cooled wort.
Priming: To add sugar to finished beer, inducing a second fermentation and producing carbon dioxide.
PVC: Plastic (polyvinyl chloride) used by homebrewers in hoses, such as siphons and beverage lines, and in plumbing pipes.
Rack: To transfer wort or beer from one container to another, separating clear liquid from sediment.
Recirculation: Action of pumping wort from the bottom of the mash tun to the surface. Used to clarify the wort. Also called “vorlauf.”
Saccharification: The conversion of starches to sugars by enzyme action.
Sanitary: Clean and nearly free of microbes; reducing risk of infection.
Single Infusion: Mashing process that involves holding the mash at one temperature step (about 148 to 154°F) until starches convert to sugars.
Siphon: Moving liquid from one vessel to another by means of gravity and a vacuum.
Slant: See Yeast Slant.
Sparging: Rinsing spent grains with hot water to recover as much sugar as possible. The process of obtaining clear wort from mash, including runoff, recirculation, and rinsing.
Specific Gravity: The density of wort: a measurement of the amount of sugars in solution.
Starter: A small volume of wort to which yeast is added, increasing its quantity before pitching.
Steeping: Soaking barley or other grains in water.
Step Mash: Mashing method that involves two or more temperature rests, beginning with the lower temperature, and increasing by means of direct heat or infusion of hotter water.
Sterile: Totally devoid of life. More exacting standard than “sanitary.”
Strike Heat: Temperature of mash water before mixing with grain. Water at the appropriate temperature is called “strike water.”
Tin: Metal often found in solders; can cause haze.
Trub: Sediment.
Underletting: Filling the area below a false bottom in a lauter tun with hot water before adding the mash.
Vinyl: Plastic (polyvinyl chloride) used by homebrewers for siphon hoses, beverage lines, and other purposes.
Whirlpool: Tank into which beer is pumped at pressure, causing a spinning motion that settles out trub.
Wort: The solution of malt sugars, water, and other compounds produced by the mashing process.
Yeast: Single cell fungus capable of fermentation.
Yeast Slant: Test tube, dish, or similar container of gelatin and growth medium (wort), prepared under sterile conditions, in which pure yeast strains are grown and stored.
Yield: Percentage by weight of the malt that will be converted to soluble substances (sugars) in the mash kettle.