The Brewing Process
Beer is a natural drink made from hops, malt barley, yeast and water. From these simple raw materials, ale is brewed to many different recipes
Barley is steeped in water and encouraged to germinate. Malt is heated (“kilned”) to prevent further growth, which also produces the malt flavours and colours. Barley malt is the main source of fermentable sugar in brewing.
Malt is transferred into the brewery and stored until it is needed. It is then milled to produce a fine mixture of flour and husks called grist.
The grist is mixed with hot water (about 65°C) and left to stand for about 90 minutes. The enzymes in the malt break down the starch to release soluble sugars (glucose and maltose). At the end of mashing, the clear sugary solution (“wort”) is “run off” leaving the insoluble “spent grains” which are typically sold to farmers for animal feed.
Yeast strain and fermentation are as critical to brewing as grape variety is to wine. Yeast is added to the cooled wort in a fermenting vessel. It feeds off the sugars and 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.
The sweet wort is boiled (for 30-90 minutes) with hops in the copper to release the hop bitterness and hoppy flavours. The bitter wort is then cooled and aerated to dissolve the oxygen that the yeast will need at the start of fermentation.
The final process depends on the type of beer being brewed. Some is run directly into casks with some yeast and priming sugar. Before it leaves the brewery however finings are added which sink to the bottom along with any solids in the beer once the container is at rest.
Filtration and Pasteurisation
Alternatively the beer is conditioned in the brewery and then filtered. Beers of this type are usually called ‘bright’ or ‘keg’ beers, and will usually be pasteurised to keep them fresh for longer.