Читать книгу Self-Sufficiency: Home Brewing - John Parkes - Страница 27

Modern methods of producing lager were pioneered in the early 19th century by brewers Gabriel Sedlmayr the Younger, who perfected dark brown lagers at the Spaten Brewery in Bavaria, and Austrian Anton Dreher, who began brewing a lager, probably of amber-red colour, in Vienna in 1840–41.

With improved modern yeast strains, most lager breweries use only short periods of cold storage, typically one to three weeks. Longer periods of storage would add hugely to the cost of lager production, although some commercial lagers are still marketed with the implication that they are matured in the ‘old-fashioned’ way.

In 1953, New Zealander Morton Coutts developed a process known as continuous fermentation (see opposite), which allowed the production of lager at a much faster pace, albeit with a reduction in flavour development. This development made possible the mass production of lager beer at a rate competitive with ales. As this technology was adopted worldwide, the light lager style emerged, quickly becoming the most popular style of beer in much of the industrialized world.

Since the 1950s, lager has displaced ale as the type of beer most consumed in the United Kingdom, and also constitutes the overwhelming majority of beer produced and sold in the United States, China, Japan, France, Italy, Russia and most, if not all, countries where beer is made and consumed.

The flavour of a lager can be quite simple, with the mildest being light lagers. Lagers with the most complex flavours are typically the darkest, although few lagers feature strong hop flavouring compared to ales of similar alcohol by volume. In general, however, lagers display less fruitiness and spiciness than ales, simply because the lower fermentation temperatures associated with lager brewing cause the yeast to produce fewer of the esters and phenols associated with those flavours. Lagers represent some of the world’s most alcoholic beers. The very strongest lagers often fall into the German-originated doppelbock style, with the strongest of these, the commercially-produced Samichlaus, reaching an ABV of 14 per cent.

The continuous fermentation plant

The drawing below shows the workings of a continuous fermenter. Wort is fed from the copper into the hold up vessel where a quantity of recycled yeast is added; the fermenting beer flows through the two continuous fermenting vessels at such a rate that the fermentation is completed when the beer flows into the yeast separator, where the yeast is separated from the beer. The yeast then flows into the yeast washer and the beer into maturation vessels (MVs). After washing with distilled water, some of the yeast is added to the hold up vessel to keep the fermentation process alive whilst the excess yeast (yeast reproduces during fermentation so there is always an excess) is sold off to make products such as yeast spreads. The carbon dioxide gas (CO₂) produced is collected, compressed and then stored for sale. Efficiently it is sometimes used to dispense the beer at the point of sale.