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Recipe – Making Sahti


One of the few “primitive” beers to survive in western Europe, Sahti is still sometimes brewed with woodfired kettles in saunas in Finland (and I’m not making this up). A sweet malty brew, it’s flavoured with juniper and fermented with a yeast commonly used in baking bread. The late great beer hunter, Michael Jackson, called it a missing link between modern times and Mesopotamia. Still considered an essential part of weddings and other festivities in some parts of the country I knew I just had to brew it at some point. An opportunity presented itself when a party to honour my mothers 60th birthday is to be held at my house in a couple of weeks (which is cutting it a bit close so we’ll see).

The main difference between Sahti and modern beer is that Sahti is turbid, that is to say the wort isn’t boiled after lautering. This leaves a lot of proteins behind resulting in a tremendous thick body and of course carries a high risk of the beer getting infected. Sahti should always be kept cold after fermentation to minimize this risk (and to keep the leftover sugars from fermenting in the container resulting in a god-awful mess). One of the few things that almost every Finn has heard about Sahti are stories of how drinking the stuff can lead to a very upset stomach, so everyone agrees that Sahti should be “well made” – what that means is not told. I took the approach of going ape-crazy with powered brewery wash and Star San, cleaning everything like a madman and disinfecting all the bits touching the wort on the cold side several times. I also decided to add hops which some people consider optional, some frown upon. By adding 10 grams and boiling the wort for about 10 minutes I cut down the risk of one the most common bacterial infections, lactobacillus, which doesn’t do well in worts with an IBU of even 10 or so. I also plan to cold crash the Sahti close to the party (provided the fermentation is finished of course) to get most of the yeast to flocculate since drinking too many live working yeast cells is probably one of the reasons behind all those stories. How well baker’s yeast flocculates is an unknown but I’ll find out soon-ish.

Sahti is traditionally mashed with a step infusion mash and there seems to be a lot of discussion about the right length and temperature of the steps, some sources calling for steps sometimes lasting over the night, temperature held steady in a sauna. I’m wondering if this is just a vestige of the need to do a complex mash with poor malt of whether all those steps are really needed to get all the proteins in to the wort. Perhaps I’ll do a Sahti experiment later with a modern infusion mash but for this brew I used a mash with 6 steps, listed below. After mashing a device called kuurna is used to filter the wort through juniper branches and berries. I substituted a device used in the making of juice from berries called “Mehumaija” – it has three compartments, a bottom part where water is boiled to provide heating, a middle chamber with an outlet to collect the juice from the uppermost part, a colander holding the berries or in this case, the mash. I used a BIAB back to make it easier to remove the mash after finishing.

Sahti can be brewed with different grains, malted or otherwise and there is some local variation in what is commonly used. I went for a darker colour, using pilsner malt as a base and adding dark rye malt that is available in convenience stores for making a low strength dark table beer. For flavour I used juniper branches and berries. It’s difficult to estimate how much to use but I knew I wanted the flavour to come through (otherwise why bother, could just brew a beer?) so I used a few branches in the lautering water, the smell at least was very strong when it boiled. Rest of the branches were used in the bottom of the biab pack along with the berries. The hops, 10 grams of Hallertau were added to the mash so it would boil for a bit. There aren’t any hard guidelines on making Sahti so I’ll just go with what seems sensible and correct the process later if need be.

The brewday didn’t go as smoothly as it could have with a new process and devices used that I didn’t have experience with. I managed to spill some wort to the floor when the outlet hose from the juicer went awol… The mash started to get stuck towards the end and I had to move the biab pack around to get it going, perhaps some rice husks would help with that. But in the end I managed to collect about 10 liters (~2,6 gallons) of wort that I cooled with my chiller (soaked in star san for hours) and racked to a better bottle. I added the baker’s yeast dissolved in some cooled wort earlier and then shook for two minutes. The bottle was lifted to the fermentation freezer that was set to 20C/68F. I’ll check on it after a few days, it is recommended that Sahti is fermented in room temperature for 2-3 days and the temperature is then lowered to around 10C/50F and the fermentation is left to finish slowly.

It was interesting to brew something different for a change and of course it is nice to be part of a tradition extending to perhaps even prehistorical times. I have to admit that I have not been a huge fan of the few glasses of Sahti that I have tasted in the past but perhaps the taste will grow on me. Or perhaps make a dry hopped Sahti? The possibilities are endless… But please,  for Pete’s sake, no tea just because the end syllable sounds like it…


Recipe :

Target Batch Size (Litres/Gallons): ~10 / ~2,6
Total Grain (Kg/Pounds): 2,5 / 5,5
Anticipated OG: ?
Anticipated SRM:  ?
Anticipated IBU: ?
Wort Boil Time: No boil

80%     2,0kg / 4,4 lbs  – Pilsner Malt, Weyermann
20%     0,5kg / 1,1 lbs – Dark Rye Malt

10,0g / 0, 35 0z. Hallertau Tradition (Pellet, 6,70% AA) in the mash (boiled for 10 minutes)



Juniper branches and berries (a few boiled in the lautering water, others at the bottom of the “kuurna”)



Baker’s yeast woken in wort cooled to 30C/86F


Add about 3 desiliters(~10 ounces) of water per kilogram of malt used in each of these steps :

30 minutes @ 38C/100F

30 minutes @ 45C/113F

30 minutes @ 55C/131F

30 minutes @ 70C/158F

30 minutes @ 85C/185F

30 minutes, boiling water

Mix the mash as evenly as possible at every stage (the mash is very dry during the first few) and insulate the kettle as well as possible to keep the temperature stable.

P1060063              P1060076

During the first stages the mash is very dry.

When finished the thickness is close to a watery porridge. (below)

Lautering :

It’s a good idea to prepare the kuurna or mehumaija during the last stages of the mash. I’m sure that a good brewer with a mash tun and rice hulls could do this without any extra equipment in the same vessel.


Pile the juniper branches to the bottom of the bag and add the berries :


Lift the hot mash on top of the branches with a suitable vessel. Wear protective gloves!


Collect the first runnings and circulate it through the grainbed until the wort clears up. At this stage collect some wort and cool it in cold water, add the yeast to this wort to “wake it”. Keep adding boiled water slowly and evenly until you have collected the intended amount of wort. After this the wort has to be cooled to pitching temperature around 18C/64F. I used my chiller coil to speed this up since I wanted to minimize the risk of contamination.


Rack the wort to the fermentation vessel (or do the cooling in it). Ferment for 2-3 days until the krausen falls and move to 10C/50F for 2-3 weeks. Sahti is traditionally served from straight of the yeastcake but moving to plastic bottles is a choice. Just make sure to always keep it in fridge temperatures to keep the CO2 from building up and breaking the bottles.

Hope this clears the process up a bit, I’ll post the tasting as soon as possible!

27/1/15 I was not home for the first day and at first was not sure if fermentation had gotten going. Just a slight ring of yeast and trub around the level of the liquid and a haze in it. I took a reading and it had fallen to 1.020 – most of the fermentation was already done. Dropped the temperature to 10C/50F.

Tasting here





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