Step 1: Water
Water quality and composition has a major impact on the brewing process and the final flavour of finished beer. Burton-on-Trent led the world in ale production with its natural supply of mineral rich, hard water, whereas soft water is the key to producing lager. Today’s modern water treatment process means brewers can adjust the composition to produce high quality beers of all styles.
Step 2: Barley
Malted barley provides a source of sugar which is converted into alcohol by yeast. Malt also gives flavour and colour to a beer; this is determined by how much the malt is heated (or kilned) before use. Pale lagers use lightly kilned malt, whereas stouts use a small amount of more highly roasted malt to provide the dark colour, along with chocolate and coffee like flavours. Brewers can use a variety of other cereals such as wheat, oats and rice to give different characteristics to the finished product.
Step 3: Hops
Hops act as a natural preservative, but also provide flavour and aroma to the beer. Hops are grown around the world, with flavours ranging from the spicy earthiness of English Goldings to the resin and citrus of American Simcoe and Cascade. German and Czech hops provide the distinctive “noble” aromas prized by lager brewers.
The brewing process
Step 4: Milling
The malted cereals, typically barley, are lightly crushed to form the grist. Grist is grain that has been separated from its chaffs, which is the husks of grain that have been separated.
Step 5: Mashing
The grist is transferred to a large container called a mash tun, where it is mixed with hot water (known to brewers as liquor) and left to steep.
During this process, naturally occurring enzymes convert the starch in the malt to sugar. That sugar then dissolves in the water to make sweet wort which is separated from the grain and run off into a new vessel called the copper to be boiled.
The left over brewers grains offer a nutritionally rich feed material and are typically stored following mashing ready for collection by local farmers to give to their animals.
Step 6: Boiling
The sweet wort is boiled together with hops in the copper. The effect hops have on the flavour of the beer depends on when brewers add them to the wort. If they’re added at the start of the boil they will add bitterness and flavour, but if added later on they will contribute to the aroma.
Step 7: Fermentation
The next stage is fermentation, the most critical process of all. Once the hopped wort cools, it is run into fermentation vessels.
Yeast is added into the mix and will convert the natural sugars into alcohol and carbon dioxide.
Each yeast strain has a different effect on the flavour of the beer, ranging from the fruitiness of English ale yeasts or the banana and spicy, clove flavours associated with European beer styles.
Historically, all British ales and stouts were fermented in open vessels with a yeast that rose to the top of the fermenting wort. These ‘top fermenting’ beers develop cloud like foaming heads, and in many cases this method is still used. When the yeast has done its job, the head settles into a thick, creamy crust, or balm, protecting the beer from air. The balm will be collected ready for re-pitching into a new fermentation.
Lagers are fermented with a different type of yeast that works at colder temperatures. This is called bottom fermentation because the yeast sinks to the bottom of the fermenting vessel. To ensure hygienic conditions, enclosed fermenters are used with a conical base which the yeast will settle into, making it easier to remove for pitching into the next fermentation.
Step 8: Maturation
Before a beer leaves the brewery it must be conditioned. For lagers there is a longer period of conditioning in the brewery at low temperature than for ales. The word lager comes from the German word lagern, meaning to store at a cold temperature.
The conditioning process itself differs depending on how the beer is to leave the brewery. For cask conditioned beers, the beer, which contains live yeast, goes directly into the cask or barrel to undergo a secondary fermentation. More hops may also be added (dry hopping) for extra aroma; finings, which bind the yeast, are also added to clarify the beer.
In the pub cellar, cask beer is a delicate product. Just like the beer undergoing fermentation in the brewery, if not handled and stored correctly, it’s vulnerable to attack from micro-organisms such as wild yeast and bacteria that can spoil the flavour and aroma of the beer.
Other beers are brought to condition in the brewery. Before they are packaged, whereas some are fined, most will be filtered and pasteurised to guard against deterioration from microbes.
Step 9: Packaging
The beer is finally packaged into kegs, casks, bottles or cans. The package type will be chosen by the brewer based on which is most suitable to preserve the characteristics and quality of the finished beer.