Brewing Beer
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Recently, a group of students on our Industrial Microbiology module here at the University of Leicester had the opportunity of taking a short field trip to visit a traditional brewery and see at first hand the process of brewing beer. In this video, you can come along with us and see for yourself.
The brewery is designed to use gravity as much as possible with a minimum of pumping of heavy liquids. Water for the brewing process flows in at the top of the building and the beer gradually makes it way down to the cellar during the stages of production. Water is heated to boiling point in tanks and then used to extract the sugars from malted grain. During the process of malting, the grain is allowed to germinate under closely controlled conditions and the starch it contains is converted into sugars. These are the main fuel for the yeast during fermentation. Malt syrup is also added to some beers for additional flavour and colour. The sugars are extracted from the malt by a process known as mashing, soaking the malt in hot water in a vessel called a mash tun. The resulting hot sweet liquid is known as wort.
Hops are the female flowers of Humulus lupulus. Hops do more than flavour the beer, they also help to preserve it and prevent spoilage. Boiling the wort with hops adds aroma, and bitterness from essential oils in the flowers.
After boiling, the liquid is very hot, so it’s cooled down by passing through this plate heat exchanger. The heat recovered is used to warm up water for the next batch of beer. Boiling also removes oxygen. Although fermentation is an anaerobic process, that is, occurring in the absence of oxygen, the brewery gives the yeast a boost at the beginning of the fermentation process by bubbling oxygen through the liquid.
After the cooled, oxygenated liquid has been transferred to the fermentation vats, yeast is added. Fermentation is carried out at around 20°C for 3-4 days. Yeast for traditional British beers are known as top yeasts, and form a mat at the surface of the beer. Lagers are brewed at colder temperatures by bottom yeasts which sink to to bottom of the vat. The brewer can tell when the beer is ready by measuring how much of the sugar has been converted into alcohol using a saccharometer.
After fermentation, the yeast removed from the top of the vats and any additional sediment is removed by a process of precipitation called fining. Then the beer flows down to the cellar and into bottles or casks for packaging and distribution. The best part of the trip was the quality control stage, where, of course, we had to taste the finished product!
The Grainstore Brewery, Davis’es Brewing Co Ltd. Station Approach, Oakham, Rutland LE15 6RE, UK.
[...] Brewing Beer [...]