Brew length: The amount of beer being made.

Combi-tun: A vessel that is used to both mash and lauter the grains.

Counterflow chiller: A type of heat exchanger in which hot wort and coolant flow in opposite directions through separate lines that are in intimate contact with each other.

Decoction: A portion of the mash that is drawn off from the main mash, heated to boiling, then returned to the main mash to effect a temperature increase.

False bottom: A perforated plate that sits above the actual bottom of the lauter tun. Its purpose is to hold the grain bed in place so that the outlet pipes do not clog during lautering. The grain bed itself, not the false bottom, serves to clarify the wort.

Hot-side aeration (HSA): Introduction of air into hot wort. Note that even though air does not actually dissolve well in hot wort, oxidation of the wort is greatly accelerated by high temperature. HSA can lead to flavor problems in the finished beer and a decreased shelf life.

Immersion chiller: A type of heat exchanger that is immersed in the hot wort while coolant flows through it, removing heat from the wort.

Infusion: A quantity of very hot (or boiling) water that is added to the mash to effect a temperature increase. Single-infusion mashing brings the temperature to a desired point with one addition of heated water.

Lauter: The process of rinsing the grain bed with hot water to extract the sugars from it. Often used interchangeably with sparge.

Mash: As a noun, it is the mixture of crushed malts (and any cereal adjuncts) and water. As a verb, it is the act of heating the crushed grains and water to specific temperatures to allow enzymatic reactions to occur. The reactions break the starches down into fermentable sugars.

Manifold: Similar in function to a false bottom, but constructed of slotted tubing.

Recirculation: The process of collecting the first runnings from the lauter tun and filtering them through the grain bed so that they are clarified. This is often referred to as the vorlauf.

Saccharification: The enzymatic reaction converting starch into sugar. This occurs during mashing.

Sparge: See lauter.

Step mashing: A mash schedule with two or more rests at temperatures that optimize conditions for different enzymes. Allows for more control over the characteristics of the finished beer than a mash with one temperature rest.

Vorlauf: See recirculation.