as little as 5 days. They attempted to redefine the term to include a forced, wood flavouring process that only they use and that the rest of the industry doesn't recognise as barrel aging. A backlash from other brewers using the term in its traditionally understood sense ensued and the outcome is, to date, unresolved. Burtonisation Burtonisation is the act of adding sulphate, often in the form of gypsum, to the water used for the brewing of beer, to bring out the flavour of the hops. The name comes from the town of Burton upon Trent which had several very successful breweries due to the chemical composition of the local water. In the early 19th century, pale ale was being successfully brewed in London. In 1822, the method had been copied by the Burton upon Trent brewer Samuel Allsopp, who got a more hoppy tasting version of the beer because of the sulphate-rich local water. The clean, crisp, bitter flavour of beer brewed by Allsopp in Burton became very popular and by 1888 there were 31 breweries in the town supplying demand for Burton Ale. The characteristic whiff of sulphur indicating the presence of sulphate ions became known as the "Burton snatch". Later, the chemist C. W. Vincent analysed the waters of Burton and identified the calcium sulphate content as being responsible for accenting the hop bitterness in Burton Ale. Burtonisation is used when a brewer wishes to accent the hops in a pale beer, such as a pale ale. It is not used for dark beers such as stout. A degree of sulphate ions in the water is also appropriate for emulation of the Czech Pilsener style, and sulphate ions are also distinctive of Dortmunder Export. Introducing magnesium sulphate into the brewing water, or "liquor", creates a rounder, fuller taste that enhances other flavours in the beer. However, excessive dosage must be avoided to prevent undesirable consequences, which could include a laxative effect. Burton Union The Burton breweries were known for a recirculating fermentation system known as the Burton Union. Invented in the 1830s, the Union system was a row of wood casks connected to a common trough by way of a series of pipes. The practical purpose of the Union system was to allow excess barm (yeast foam) to be expelled from the casks without leaving excessive amounts of head space within the casks; the system was quickly