|
Malting
The whisky making process starts with cereal. Cereals are high in starches which need to be converted into soluble sugars in order to make alcohol. This happens naturally during germination, so hot water is added and the mixture warmed until the cereal thinks it is time to grow. This is called malting. Milling When the malt is dry, it is grinded to make a kind of coarse flour which will be used in the next operations. This flour is called grist. Malt grinding is done with a malt mill in the distillery itself. Nearly all the distilleries use the same kind of mill, traditionally made in England, in Leeds, which is sometimes hard to accept for a real Scot. Mashing The grist will be mixed with hot water in the mash tun. Generally one volume of grist is mixed up with 4 volumes of water. In this operation, 3 successive waters are used, at a temperature between 63 and 95%. A mash tun can contain up to 25000 litres and has a double bottom with thin perforations to let the wort (sugared liquid resulting of the brewing operation) flow out, retaining bigger parts which will be sold as cattle food. In order to facilitate the process, mash tun have rotating blades. The waste is called draff. The first operation, taking about 1 hour, will change the starch in fermenting sugars. The mix of water and grist looks like a kind of traditional porridge. This sugared juice is called wort. The remainders will be brewed 3 to 4 times, in order to get a maximum of wort. Fermentation The wort is cooled to 20°C and pumped into washbacks, where yeast is added and fermentation begins. The living yeast feeds on the sugars, producing alcohol and small quantities of other compounds known as congeners, which contribute to the flavour of the whisky. Carbon dioxide is also produced and the wash froths violently. Revolving switchers cut the head to prevent it overflowing. After about 2 days the fermentation dies down and the wash contains 6-8% alcohol by volume. Distilling This stage is for the wash to be distilled. Whether using a column still for continuous distillation or a pot still for batch distillation, the purpose is the same: to extract alcohol spirit from the wash. The essential process is simple: the wash is boiled and, as alcohol boils at a lower temperature than water, the alcohol is driven off the wash as vapour; this vapour is then condensed into liquid. With pot still distillation, the spirit is condensed either in a shell and tube condenser or and old fashioned worm tub, which produces a heavier, oilier style of spirit. Most whisky is distilled twice – the first time in a wash still (known as a “beer still” in the US), the second time in a spirit still. Irish whiskey is traditional triple distilled to create an even purer spirit. Maturation The process that turns raw, clear, new make into the richly hued, complex tasting drink we know as whisky is maturation. The length of time for maturation varies, depending on climatic conditions, the size and type of the casks used, and legal requirements-at least three years for scotch. |
DISCOVERY WHISKY: Manufacturing process