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# A Brewing Glossary

Airlock
  A device that lets CO2 escape from the fermentor without letting outside air or contaminants in.
Alpha Acid
  The primary bittering agent in hops. Also known as humulone. Hops are rated by their percentage of alpha acid. The abbreviation for alpha acid is "AA".
Aroma Hops
  Hops noted for their aroma instead of their bitterness. They are low in alpha acids, the resins that cause the bitterness in beer. These are usually added towards the end of the boil, or used for dry-hopping. Examples include Cascade, Hallertau and Tettnang.
Beer Kit
  The simplest way to make beer. Consists of a can of malt extract that is pre-hopped with a pack of dry yeast under the lid. The usual procedure with these kits is to pour the can into a plastic bucket with water, add one or two cans of table sugar, and spinkle the yeast on top. This rarely results in a great beer.
Blow-Off Tube
  Made of one-inch inside diameter vinyl tubing, one end of a blow-off tube is stuck tightly into the neck of a carboy with the other end stuck in a large jar of water. They are used when fermenting in five gallon carboys so that the foam, or krausen, developed during fermentation is expelled into the jar. When fermentation has slowed down and the krausen subsides, it should be replaced with an airlock.
Burton Salts
  A mixture of salts and minerals designed to mimic the chemistry of Burton-on-Trent, the birthplace of pale ale. A teaspoon per five gallons is plenty to make soft or mild water reasonably similar to the water from the brewing region.
Conversion
  The process of changing starch into sugar during the mash. Enyzymes in the mash break down the complex starch molecules into simpler sugars.
Decoction
  A method of mashing, traditionally used with lagers and under-modified malts. The mash is started at a lower temperature, then a portion of the mash is removed, boiled, and added back to the mash. This raises the mash to the next temperature needed. Decoction mashing gives a beer a maltiness not achievable with any other method.
Ester
  A chemical compound formed through the oxidation of certain alcohols. The aromas of esters are fruity, and the smells we associate with apples, bananas, etc., are in fact esters. A beer with an abundance of fruity flavor and aroma is an estery beer. Ales tend to be estery. Beers fermented at too high of a temperature can produce more esters than are desired.
Fermentation
  When yeast consume sugar, they produce alcohol and carbon dioxide. This process is known as fermentation.
Grist
  The total amount of malt and grains used in a recipe. Also known as a grain-bill.
Hydrate
  The opposite of dehydrate. Dry yeast is just that, dry, and must be reconstituted with water before using for best results. Boil a cup of water, let it cool to a lukewarm temperature, sprinkle the dry yeast on top, and cover with foil. It will be ready to pitch in twenty minutes.
Hydrometer
  A device used to measure the specific gravity of a liquid. A hydrometer can tell a brewer how much residual sugar is in his or her wort, thus predicting the strength of the finished product.
IBU
  A measurement of bitterness in beer. Stands for Internation Bittering Units.
Krausen
  The layer of foam created on top of fermenting beer. Also refers to a portion of fermenting beer added to finished beer in order to cause carbonation.
Light-Struck
  Beer will develop a skunky or catty taste when exposed to light, especially sunlight. For this reason, beer should be put in brown glass bottles. If you want to know what lightstruck beer tastes like, pick up a green glass bottle of Heineken or Grolsch that has been sitting under flourescent lights in the store.
Lovibond
  A measurement of color, particularly in brewing ingredients. Using lovibond, you can calculate your beer's color from its ingredients. Lovibond is measured in degrees, and "17L" would be read as 17 degrees lovibond, which is also the color of Michelob Dark! The lovibond scale tops off at 40L, the color of black stout.
Malt
  Germinated grain. Regular grain kernels are not suitable for mashing by themselves. Malted grains have been soaked in water, allowed to germinate, or start growing, and then dried and cured. This process creates the enzymes responsible for converting starch to sugar, and makes the starch in the grain accessible to those enzymes. Different malting and curing procedures create the wide variety of malts vailable.
Mashing
  A process of making beer from scratch. Instead of using malt extract to make wort, mashing makes wort from the basic malt grains. The grains are crushed, placed in an insulated container with pre-heated water, and left to sit for an hour or so at about 150 degrees. This converts the starch in the grains to fermentable sugars. Then the mash is slowly rinsed to extract the sugars. Once mashing is complete, the rest of the brewing procedure is the same.
Original Gravity
  See Specific Gravity.
Pitch
  The process of adding yeast to wort to start fermentation. Yeast is not thrown in the fermentor with an overhand throw like in baseball, but rather poured in by hand.
Priming
  The process of adding sugar to finished beer for bottling. The remaining yeast in the beer ferment this sugar to cause carbonation.
Racking
  A fancy term for siphoning or transfering beer from one container to another.
Smack Pack
  A form of liquid yeast. They consist of a pouch of liquid yeast with a smaller pouch of starter wort inside. When the smack pack is "smacked", the inner pouch ruptures and the yeast begin growing in the starter. The pack will expand to about two inches thick in a few days, ready for pitching.
Sparge
  The process of rinsing sugars from the grain bed after the mash. Sparging is also called lautering. Sparging is typically done in a lauter tun, which holds the grain above a false bottom perferated with tiny holes. This allows the liquid to gently flow through the grains. A common ailment in sparging is the stuck-sparge. This results when the grain bed is clogged with sediment or gummy substances, clogging the flow.
Specific Gravity
  A measurement of density, where water has a density of 1.000. Dissolved sugars will increase the density of water. Thus, specific gravity will measure the amount of fermentable sugar present in wort. A gravity measurement taken before fermentation starts is known as original gravity, while a measurement taken after fermentation is known as terminal gravity, or final gravity. Worts with a gravity over 1.075 are known as high-gravity worts.
Starter
  A tiny portion of wort used to grow the yeast to pitching proportions. A few hundred yeast cells taken from a slant would be overwhelmed by five gallons of beer, so they are given a couple of ounces to chew on first, then a quart, and finally, when they are numerous enough, added to the carboy of wort. Smack-packs have their own starter wort included, and they can be pitched directly to the carboy when ready.
Steeping
  The process of soaking grains in hot water to extract their flavor. This is different than mashing, as no conversion takes place. Steeping is often used by extract brewers to add a multitude of malt flavors to their wort without having to mash.
Torrified Grain
  Adjunct grains that have been processed to make them suitable for mashing. They resemble "puffed" breakfast cereals, such as puffed wheat, rice puffs, etc.
Wort
  Unfermented, or raw, beer. In Jamaica they make a non-alcoholic drink called malta that is essentially wort.

©David Johnson, Stephen Lowrie, 1997 - 2008
Permission is given to freely copy and redistribute this document.

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