Sahti is a traditional beer from Finland made from a variety of grains, malted and unmalted, including barley, rye, wheat, and oats; sometimes bread made from these grains is fermented instead of malt itself. Traditionally the beer is flavored with juniper berries in addition to, or instead of, hops; the mash is filtered through juniper twigs through a trough-shaped tun called a kuurna in Finnish. Sahti has a distinct banana flavor due to the production of isoamyl acetate by the yeast. Sahti is a top-fermented brew (ale), and while baking yeast has been used traditionally, ale yeast may also be used in fermenting.
The end product is a cloudy, mildly alcoholic beer with yeasty and phenolic flavors and a distinct taste similar to banana. Sahti is traditionally homebrewed but in recent years commercial versions have become available. Commercial Sahti usually has around eight percent ABV. In Finland, due to the higher percentage of alcohol in Sahti, it is only sold in pubs or state-owned Alko stores. Sahti has to be stored cold until consumption and is therefore not available in all Alko branches.
Finnish Sahti 
Within Finland, sahti has differing characteristics depending on which part of the country it is from. It is often known as Tavastian beer (well-known sahti areas, such as Sysmä and Lammi, are in Tavastia) but it is also made in Finland Proper and some parts of Central Finland. There is also related a beer on the Swedish island of Gotland (known as Gotlandsdricke, Gotlandsdricku or Dricku) and the Estonian island of Saaremaa (known as "Koduõlu" or "Taluõlu"). Every couple of years there is a Juniper Beer-Brewing Championship for homebrewers of these three countries.
Sahti in other countries 
Finnish Sahti has Protected Geographical Status in Europe. In the United States, Sahti has been the subject of recent interest by homebrewers and microbreweries; in 2008, Dogfish Head Brewery released a beer called Sah'tea, a collaboration with Finnish brewer Juha Ikonen, that was a hybrid of traditional Sahti and Chai tea. New Belgium Brewing Company of Colorado is now brewing a Sahti Ale.  Samuel Adams also brews a Sahti called "Norse Legend."
Brewing process 
Traditionally, Sahti is brewed using a long step infusion mash that may last up to six hours, after which the wort is lautered through the kuurna. Unlike most beers, traditional Sahti wort goes straight from the lauter tun to the fermenter without boiling. This gives it a relatively short shelf-life and may cause some characteristic sour flavors to develop from Lactobacillus bacteria.
Commercial Sahti brands 
- Panimoravintola Beer Hunter's: Muffloni Sahti (from Pori)
- Finlandia Sahti and Finlandia Strong Sahti  (from Sastamala)
- Hartolan Sahti, known as Krouvin Sahti and Punakallion Sahti.
- Hollolan Hirvi Kivisahti
- Huvila sahti (from Savonlinna)
- Joutsan Sahti
- Lammin Sahti
- Tiinan Sahti (from Sysmä)
- Samuel Adams: Norse Legend sahti (from Boston, Massachusetts, U.S.A.)
- Dogfish Head Brewery: Sah'Tea (from Milton, Delaware, U.S.A.) made with chai tea and juniper berries
- Stadin Panimo: Stadin Sahti (from Helsinki)
- Sahti Ale - New Belgium Brewing Co. (from Fort Collins, Colorado, U.S.A.) http://www.newbelgium.com/beer/detail.aspx?id=b3fe1756-9dcf-4e2a-97d0-37542800aa09
- EU Profile-Sahti (accessed 07/06/2009)
- Burkhard Bilger, "A Better Brew." The New Yorker. November 24, 2008 (accessed 01/27/09)
- R. Mosher, Radical Brewing. (Boulder, CO: Brewers Publications, 2004), 244-5.