Glossary
As befits a centuries-old practice, brewing comes with its own often pleasingly medieval-sounding vocabulary, many of it borrowed from German and Old English, including the witchy-sounding ‘wort’ (properly pronounced ‘wert’, if you’re being pedantic), and ‘copper’, a traditional name for the boil kettle.
Unmalted grains added to a mash; sometimes other additions too (spices or flavourings).
ALPHA ACIDS (AA)
Acids in hops which contribute towards the overall bitterness of the beer.
AERATING
Oxygenating boiled wort to allow yeast to thrive.
AROMA HOPS
Hops added after the first half-hour or so of the boil: they are usually low in alpha acids and provide aroma.
ATTENUATION
Conversion of sugar to CO2 and alcohol (by yeast).
BITTERING HOPS
Hops added at the start of the boil: after an hour of boiling they give up their desired bitter flavours.
BOILING
The process of infusing wort with the bitterness, flavour and aroma of hops. Done in a boil kettle, aka a copper.
BOTTLING/KEGGING
Transferring beer to a receptacle suitable for convenient consumption.
CONDITIONING
Resting beer in a bottle, barrel, cask or keg to allow it to carbonate and develop in flavour.
FERMENTING
The process by which yeast converts fermentable sugars into alcohol and CO2.
FINING
A substance added during the brewing process to clarify the beer (Protofloc or Irish moss).
FLAMEOUT
Literally, the moment when the heat under the boil is extinguished: also refers to the moment when hops are added to the wort to impart maximum aroma. See also whirlpool.
FLOCCULATION
The act of clustering or clumping together, in the case of brewing, yeast solids in the fermenter.
GRAVITY, SPECIFIC
The density of liquid (in brewing, the concentration of sugar in liquid).
GRIST
Ground grain for mashing.
KRAUSEN
A foam of proteins and yeast that forms on the wort during primary fermentation. Looks disturbing, is actually a reassuring sign that all is going well.
The process of rinsing the grains of all their fermentable sugars and taking the wort to a pre-boil volume. It involves two stages: recirculation (aka vorlauf), using the existing water in the tun, and sparging: sprinkling fresh water over the grain bed.
LIQUOR
Water used directly in a brew. The total volume needed is split into strike water (used to mash) and sparge water (in the sparging process).
MASH HOPS
Hops added in the mash for bittering. An uncommon practice.
MASHING
The process of soaking grains and adjuncts in hot water in the mash tun to extract sugars. Can be done at one temperature (single-rest) or variable-temperature stages (multi-rest). Mashing out is the process of raising the temperature sharply at the end of the infusion to halt enzyme action.
PITCHING
Adding yeast to wort.
PRIMING
Adding sugar (or malt extract, or occasionally yeast) to wort before bottling to facilitate the creation of carbonation in the bottle.
RACKING
Transferring wort from one vessel to another, typically from a primary fermenter to a second, or from a fermenter to a priming vessel.
TRUB
Unwanted sediment in the boil kettle and fermenter, consisting mainly of hop matter, proteins and dead yeast cells.
WHIRLPOOL
When brewers spin the post-boil wort at high speed to form a mound of undesirable solids in the middle. ‘Whirlpool hops’ are sometimes added at this stage.
WORT
Sweet liquid taken from the tun after the mash, containing fermentable sugars.