Sahti is a traditional, slightly cloudy, strong beer produced by fermentation. It is neither pasteurized nor filtered, and the fermentation is left to run its course. Sahti is traditionally prepared from raw materials including malted cereals (rye, barley, wheat and oats) and, usually, hops, which are fermented using baker’s yeast or harvested yeast. It takes about 20 kg of malt and 50 g of yeast to make 50 liters of sahti. The original gravity of the wort is at least 19°Plato and the alcohol content varies between 6 % and 12 % by volume. The pH is less than 5. The color varies from yellow to dark brown depending on the raw materials used. Because of the high residual-sugar content, fresh sahti is slightly sweet tasting. Sahti is brewed by gradually adding water to the mixture of malt and cereals, starting at a temperature of around 40°C, which is increased to around 100°C by the time the last water is added. This is known as ‘mashing,’ and in some places this phase also includes boiling the mash. The heating times vary by producer from short to a thorough boiling. Next, the wort is strained in a trough or vat, at which point hops may be added. Traditionally, juniper twigs and rye straw are used for straining the wort, which is then fermented into sahti using baker’s or harvested yeast. Top fermentation is used. The main fermentation takes around three days at room temperature or slightly cooler, after which the sahti is kept cool for at least one week. The alcohol comes exclusively from the sugar in the malts and other cereals. Sahti is made according to traditional methods using traditional raw materials and no additives. The finished product is neither filtered nor pasteurized, but drunk fresh. Sahti has a long history: the brewing instructions have probably been handed down from generation to generation for thousands of years, although written records do not date back very far. Sahti was, and still is, used as a festive drink and forms part of the living rural culture in its home regions of Kanta-Häme, Päijat-Häme and Pohjois-Satakunta in southern Finland. Sahti production is a craft and has its own special equipment: the wooden trough is characteristic. The earliest written reference to the traditional nature of sahti and its geographical distribution dates from 1792. It is among the most unusual and clearly distinguishable malt-based drinks in the world and is one of the last “original” beers in Western Europe. It is produced for home consumption and a small commercial market around the production area. The original tradition is in danger of being lost, with only four active commercial producers. A competition has been organized in recent years also open to home brewers to promote the production of traditional sahti.
Image: Archivio Slow Food