How we brew our beer
Time for the technical stuff. We've spent a lot of time telling you that Birkenhead Lager is a 'premium craft beer of quality and distinction.' But we could be lying, it could all be blatant propaganda. So, to show you we're not just talking a good game, but actually playing one as well, we'll take you through our brewing process.
There are five brewing steps involved in the production of our truly fine beer.
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Malting
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Barley is first steeped in cold water for 45 to 72 hours, the water being drained off about once a day. It's then placed in slowly revolving drums or in shallow tanks equipped with plows. As the wet grain is stirred and aerated, it begins to germinate. This process produces several enzymes in the grain, the most important being malt diastase, which changes starch into sugar. Germination is allowed for about 6 days and then the sprouted barley, now called malt, is finally kiln-dried. Kilning stops germination and produces substances that give an aromatic flavour to the beer. By varying the heat, the malt can be toasted from light tan to dark brown and the colour of the beer can be partially determined this way. About 5 kg of barley malt is used for each 30-litre barrel of beer.
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Mashing
Crushing the malted grain between iron rollers begins brewing. The fine powder produced - called grist - is then mixed with warm water until it forms a mash of porridge-like consistency to which the supplementary grains can then be added. If raw grain is used, it must first undergo boiling, but when cereals like corn are used as malt adjuncts, pre-cooking is not required. At this stage, the temperature of the mash is raised in steps from 38° C to 77° C, with time allowed at each step for the various enzymes to do their thing. The finished mash is allowed to rest for a short time during which the spent malt settles to the bottom of the mash tub. There it forms a filter bed, through which the liquor - now called wort - is drawn off. Hot water is run through the residue to rinse out, or sparge, the remaining wort from the spent grain.
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Cooking
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The wort is now collected in copper kettles and boiled with the hops. Next, the hops are screened out, and the wort is passed through a cooler and run into vats, where fermentation begins.
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Fermentation
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To begin fermentation, pure yeast culture is added in a ratio of approximately 0.45 kg per barrel of wort. This culture is generally reserved from a previous brewing of the same kind of beer. Bottom-fermenting yeast (which oddly enough settles to the bottom) is used for lager beer, and top-fermenting yeast (no comment!) is generally used for ale. Fermentation continues for a number of days, depending on the type of beer brewed. Once the fermentation is judged to be complete, the yeast is skimmed off or allowed to settle, and the beer is drawn off for cellaring.
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Cellaring
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The beer is allowed to age for 3 weeks to 3 months in storage vats, during which time it clarifies and its flavour develops. Often, when it is fully matured, a small amount of fresh wort or sugar is added, and the beer is placed in pressure tanks for some final fermenting. This produces the carbon dioxide gas and gives you that all-important head. Finally, the beer is usually pasteurised and filtered, and is then sealed in pitch-lined kegs or packaged in individual bottles or cans for rapid, yet dignified consumption. (for the first few anyway!)
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