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How Beer is Made
Beer is a natural drink made from malted cereal (usually barley) hops, yeast
and water.
The brewing of beer is based on an ancient and simple principle - natural
fermentable sugars are extracted from a malted cereal using hot water
(known as mashing).
Malting
But first the cereal has to be malted. The barley is soaked in water and
encouraged to germinate – a process that starts to release fermentable
sugars. The grain is then heated to prevent further growth, which also
produces the multitude of malt flavours and colour that we find in our
beers.
Milling
The malt is then milled to produce a fine mixture of flour and husks known
as grist.
Mashing
The grist is then mixed with hot water and left to stand – a process
known as mashing. The enzymes in the malt break down the starch to release
soluble sugars – glucose and maltose.
At the end of mashing a clear sugary solution known as wort, is run-off
leaving the insoluble spent grains which are sold to farmers for animal
feed.
Boiling
The sweet wort is boiled with hops in a vessel called a copper to release
the hop flavours and characteristics.
The bitter wort is the cooled and aerated to dissolve the oxygen that the
yeast will need to begin the fermentation.
Fermenting
Yeast is added to the cooled wort in a fermenting vessel. A living organism,
the yeast feeds off the sugars and other nutrients extracted from the
malt, producing carbon dioxide and alcohol.
When most of the sugars have been used up, the yeast becomes inactive
and the fermentation is complete.
Conditioning, filtration and pasteurisation
The final process depends upon the type of beer being produced.
Most beer is conditioned in the brewery. After fermentation, the beer
is chilled in large tanks, a process known as lagering.
Most of the yeast sinks to the bottom and it is then filtered and pasteurised
to keep it fresh longer, before being put into a keg, bottle or can.
Some beer, especially in the United Kingdom, is conditioned, in the cask
or bottle from which it is served. This is know as cask-conditioned beer
or real ale. The beer, which contains a small amount of yeast from the
fermenting vessel is run into a cask or bottle before it leaves the brewery
and continues a process of secondary fermentation in the container.
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