Source: Jukka Heino (firstname.lastname@example.org), r.c.b., 3/7/94
Adding hops to sahti is not necessary. Many traditional recipes don't include hops.
Boil the mash shortly and stir it continuously. (This is the biggest difference between making beer and sahti.) The mash should became a bit reddish in colour.
Put the juniper branches on the bottom of the lauter tun and add the mash. Recirculate the first turbid run off to get clear wort. Sparge slowly with boiling water. (The use of boiling water is another major difference between making sahti and beer.) Collect 12 litres of wort. Original gravity of the wort should be about 1100. Take 1/2 litres of wort and cool it to 25 C temperature and pitch the yeast. Boil the rest of the wort quickly and add hops. Cool the boiling wort rapidly to pitching temperature (25 C), put it in the fermentation bin and add the starter culture. It is better to keep the fermentation temperature below 20 C. So the fermentation takes a longer time but the taste is better.
Let the sahti ferment for about a week so that the spesefic gravity is around 1030 - 1040. It shoud still have a bit sweet taste. Bottle the sahti to bottles with easily openable caps and put in a cool (10 C) place. You should let the extra CO2 out from the bottles for every second day or you may use loose caps. After a few days you should taste the sahti. When the sweetness is optimal (it depends on your taste), fix the caps and put sahti in a cold place. The lagering temperature should be close to freezing point but not below. Let it mature for some days.
Drink and enjoy. Optimal serving temperature is about 8 C.