18 lbs 2-Row
5 Lbs Rye
4 Lbs Munich
2 oz Hallertau (3.8%AA) during sparge
2oz Juniper Berries (in Mash)
2.25oz Priming Sugar
Wyeast Weihenstephen Wheat (3068)
Wyeast Bavarian Wheat Blend (3056)
Bring slightly over 8 gal of water to a boil. Place Juniper boughs in the boiling water for 2 minutes to sanitize Juniper and flavor water (Strike Water). Allow the water to cool to 132°F. Once the water is back down to 132°F, add the milled grains (Grist) and stir to evenly distribute and break up any clumps (Mash In). This should drop the overall temperature to around 120°F. Add the crushed Juniper berries to the mash. Slowly raise temp to 160°F over 45 min, if possible (somewhat Step Infusion Mashing). Once the mash is at 160°F, let rest for 60min. Do your best to maintain this temperature to ensure the best conversion of starches to sugars (Saccharification). Also at this time if desired, begin heating up several granite stones to 500°F in the oven or on a grill/burner/campfire for 3 hours.
During the mash, prepare the Kuurna by placing wooden slats perpendicular to the length of the Kuurna to create a small space at the bottom for the wort to flow through. Take the previously sanitized Juniper and create a lattice of the Juniper boughs to serve as a sieve (or lay some Juniper boughs in bottom of your Lauter Tun). Try and make a uniform bed of Juniper for the grains to rest on and hopefully not fall through. Sprinkle the hops over the top of the Juniper lattice. Also during this mash time, heat up 4gal of water to 175°F to Sparge with once the mash is done.
Once the 60min mash is up, raise temp of mash to 168°F (Mash Out) for 5 min. This decreases the viscosity of the Wort (unfermented sugary liquid). Once the 5min us up, pour the mash onto bed of juniper and let Juniper filter out grains (Lauter). Slowly start draining Kuurna or Lauter Tun. After some has drained out, pour it back over the grain bed until the wort runs clear of grain. The wort acquired from lautering the grains this first time is what would be used to make tupulisahti (strong sahti) for the men to drink.
Once the wort has been filtered from the grain, slowly pour (drip) 4gal of Sparge water over the grains to extract all the remaining sugars. To ensure the best extraction of the sugars, this process should be slow due to the rate of water slowly flowing through the grain bed. Once the first bit has drained out, recirculate the Sparge water by pouring over the grains one more time. This secondary rinsing of the grains is what would have become jälkijuoma (lit. nosedrops) aka “naisten sahti” (lit. women sahti) eg. weak sahti for the women and priests. It is know however, that these two runnings were sometimes simply mixed together.
Once all the wort has been collected, bring the wort to boil for 20min to sterilize and stabilize the wort. This boil can also be achieved with the previously heated rocks (Kivisahti). Carefully place the hot granite stones in a stainless steel colander and lower the stones into the wort. There will be a lot of spitting and sputtering on the initial contact with the rocks, so be sure to have a safe way to lower the rocks into the brew pot. Traditionally Sahti is not boiled, so to keep it truly authentic, forgo the boil (although boiling with stones is another traditional method).
After boiling the wort for 20min, begin chilling the wort down to 75°F. Once the wort is cooler than 100°F, aggressively stir the wort to aerate it. This replenishes the oxygen that was lost during the boil and helps to provide an ideal environment for the yeast to thrive. Split into fermenters (carboys)(traditionally a Juniper cask) and pitch yeast. At this point, make sure to sanitize anything that comes in contact with the wort to minimize the chance of infection.
Transfer the wort into a fermenter (or split into 2 fermenters) and pitch the yeast. You can also measure the Starting Gravity at this point. Seal up the fermenter(s) with an airlock and let the Sahti ferment for several days (up to a week). The primary fermentation will likely be vigorous and you may want to employ the use of a blow-off tube to avoid any potential explosions. After the primary fermentation, Rack (the transferring of beer/wine between containers to remove sediment, dormant yeast, etc…) the beer into a secondary container for secondary fermentation for up to a week (take another gravity reading at this point). You can now take the final gravity reading and bottle/keg the beer!
To make a truly historic Sahti;
Brew in a sauna
Use unmodified malts
Use a step-infusion mash schedule
Lauter & Sparge the wort through a Kuurna lined with Juniper boughs
Forgo the boil (or use hot stones to do a short boil – Kivisahti)
Ferment with Finnish bakers yeast
Ferment the wort in a (Juniper) cask
After primary fermentation (~3-5 days) tap the cask and enjoy the Sahti directly from it
Drink the Sahti using a Haarikka (wooden two handled cup/tankard) passing it around among friends!