A brewery takes the four ingredients: water,
hops,
malt and
yeast, and makes them into
beer. Traditionally, hops came from an
oast house, malt from a
maltings, water from a well, and live yeast from the previous brew.
Stage 1: Mashing
Water (referred to in the trade as liquor, despite the fact that it contains no alcohol at this point) is heated to above 90
oC in a
kettle. Sometimes minerals such as
gypsum are added to alter the mineral content. Pipes feed this hot water into a large vessel called a
mash tun, where milled malt (
grist) and hops are added. The mash tun contains paddles which stir the mash, dissolving the maximum amount of sugars from the malt, and
alpha acids from the hops.
The resulting mash is strained, using additional water to sparge, i.e. wash any remaining sugars from the dregs.
This liquid now referred to as wort (pronounced wurt), is cooled and passed to the fermenting vessel.
Stage 2: Fermentation
Yeast is added to the wort, and left in the fermenting vessel, which can be traditionally rectangular and open to the air - called Yorkshire squares, or enclosed in a cylinder with ventilation at the top. For an
ale, fermentation takes place above ground at room temperature and takes about a week. For a
lager, this takes longer - about a month, and requires chilling to around 5
oC.
Stage 3: Bottling/Casking
One of two processes happens. Either the beer is filtered, pasteurised and carbonated, then put into bottles and
kegs, or
isinglass is added as
finings to precipitate out dead yeast (the finings do not end up in the beer). In this case some sugar is added to assist secondary fermentation or
conditioning, and the beer is put into bottles as
bottle conditioned beer, or
casks as
real ale for distribution to pubs.