Definitions of commonly-used brewing terms.
Adjunct: Any fermentable ingredient in beer other than malted barley (examples: rice, wheat, flaked maize)
Ale: A type of beer fermented with a top-fermenting yeast (saccharomyces cerevisiae) at temperatures usually between 55-70 degrees Fahrenheit (16-21 Celsius). Some U.S. state laws require beers with a higher alcohol content to be labeled as "ales" even if they really are lagers.
Alpha Acid: A measurement of the bitterness potential of hops. A hop with 10% alpha acid will provide more than one with 4% alpha acid. The bitterness potential of the hops will be lost over time if they are not stored properly (air tight, oxygen impermeable bags; very cold storage temperatures).
Aroma: What the beer smells like. Different styles will have different aromas (some with more malt character, others with more hops).
Attenuation: A measurement of how much of the wort has been fermented into alcohol and carbon dioxide.
Beer: An alcoholic beverage produced by the fermentation of grain. It has been said that brewers make wort (see below), but yeast makes beer.
Body: The mouth-feel (how "heavy" it feels in your mouth) of a beer.
Carboy: A large glass bottle in which to ferment wort.
Chill haze: Haze caused by protein compounds produced at cold temperatures. Can be reduced with finings (or by serving the beer at about 50 F).
Cold break: Proteins that precipitate out of the wort when it is being cooled.
Conditioning: This primarily refers to the process of carbonating beer. It can also refer to the proper aging of lagers and some ales.
Dextrins: Unfermentable sugars that contribute to the beer's body.
Diacetyl: (pronounced dye AS uh til) Buttery or butterscotch flavors in beer. It is produced by some types of yeast, abbreviated fermentation, or bacterial infection.
Esters: Fruity flavors and smells in a beer produced by certain types of yeast. Levels of esters are increased at higher fermentation temperatures.
Fermentation: The process in which yeast converts sugars to alcohol and carbon dioxide.
Fining: Different ingredients (e.g. Irish Moss, isinglass) added either to the wort or to the finished beer to help make it more clear by bonding to various proteins and precipitating out of solution.
Finish: A beer's aftertaste. Contrary to popular opinion, beer should have an aftertaste.
Flocculation: A measurement of how completely and/or quickly the yeast settles out of suspension in the wort.
Grist: Milled malts and adjuncts to be mixed with hot water to form the mash.
Gyle: Unfermented wort. It is sometimes reserved for adding to fermented beer for conditioning (carbonation).
Homebrew Bitterness Units (HBUs): A less precise manner (than IBUs, below) of measuring the bitterness of a given beer. The number of HBUs is determined by taking the number of ounces of bittering hops and multiplying it by the hops' alpha acid percentage e.g. two ounces of 5% AA hops would be 10 HBU (2x5 = 10).
Hot break: Proteins that precipitate out of the wort when it is being boiled.
International Bittering Units (IBUs): A standard for measuring the bitterness of a given beer. One IBU = one milligram of isomerized alpha acid in one liter of beer.
Kraeusen: (pronounced KROY zen) the foamy head the comes to the top of the wort at the beginning of fermentation.
Kraeusening: The process of adding some gyle (see above) to fermented beer to produce carbonation.
Lager: (verb) From German, meaning "to store." The process of storing a beer around freezing temperatures for a period of time for conditioning purposes.
Lager: (noun) A type of beer fermented with a bottom-fermenting yeast (saccharomyces uvarum) at temperatures usually between 40-50 degrees Fahrenheit (4-10 Celsius) and then lagered (see above) for conditioning purposes.
Lautering: Straining the grains and husks from the wort after mashing by means of a lauter-tun.
Malt Extract: Wort that has been dehydrated into either a syrup or powder.
Mashing: Converting grain starches into sugars through a process of careful temperature control.
Pitching: Adding the yeast to the wort. The term came about because brewers used to skim the kraeusen with pitchers and use that yeast as a starter for the next batch.
Primary: (or primary fermentation) The initial fermentation or the container in which initial fermentation occurs.
Priming: Adding sugars to the beer before bottling or kegging to naturally carbonate it.
Racking: Transferring beer from one container to another.
Recirculation: See vorlauf below.
Secondary: (or secondary fermentation) The final, slower portion of fermentation and conditioning or the containter in which secondary fermentation occurs.
Sparging: Pouring or sprinkling hot water on the mash to rinse all the sugars from the grains.
Trub: (pronounced TROOB) The proteins, dead yeast, and other flotsam in the wort. During fermentation, it will fall to the bottom of the carboy.
Vorlauf: (pronounced FOR louf--the ou is like the ow in cow) Recirculation of cloudy wort through the mash bed to clarify it before running it off to the kettle.
Wilhelm: (pronounced VILL helm) The spent grain left over in the mash tun. Its removal requires someone with a strong back and a weak mind. This term was originally coined by our esteemed webmaster.
Wort: (pronounced WERT) The sweet liquid produced by mashing (or from rehydrating malt extract) which will be fermented into beer.
Yeast: Our little microbial friends whose sole purpose in life is to convert sugar into alcohol and carbon dioxide. God bless 'em.
Zymurgy: (pronounced ZYE muhr jee) The science of fermentation through brewing. Also the penultimate word in my dictionary.