Brewing Finnish Sahti

After posting some information on using rye malts in beer and on Finnish 100% rye-malt low-alcoholic beer, kotikalja, I got several requests to post a recipe for Finnish sahti. I guess that the motivation for the requests was that Michael Jackson in his New World Guide to Beer mentions sahti as one of the most special beers in the world.

Since sahti is traditionally brewed by each household themselves, there is no one single accurate recipe for sahti. Each brewer has his/hers own version, and since the recipe isn't usually in a written form but as a "awareness of the process", the recipe usually varies more or less between the brews.

I would recommend the following process:

This recipe is for 35-60 liters of sahti, smaller batches can be made by using the ingredients in smaller amounts.

• 20 kg sahti malt mix, a mixture of pale barley malt and pilsner malt and possibly some dark caramel malt will do well
• 1-2 kg dark rye malt
• juniper twigs
• yeast (traditionally baking yeast)

Mashing

Put the malts to one or several big enough but not too deep containers, two 40 liters containers will do well. Add ~5 liters of boiling water, stir well. During next ~6 hours: twice an hour add ~2.5 liters of boiling water and stir. The amount of water and time are approximate. This method will not keep the temperature near the optimal 65-68 C, but I believe that the time will do the thing. A hot place to mash would probably raise extract rate, though I don't know if it is worth it. Insulating the containers would also help.

Filtering

The junipers are used for filtering the mash. The filtering device should be big enough to fit all of the mash. Traditional Finnish filtering device, "kuurna" is a U-shaped longish device. The profile is about as follows, the dimensions about 150x40x30 cm (lxwxh)

        I                     I
        I                     I
        ImmmmmmmmmmmmmmmmmmmmmI
        ImmmmmmmmmmmmmmmmmmmmmI <- the mash 
         \:::::::::::::::::::/  <- the juniper twigs
          \- - - - - - - - -/   <- wooden support for the juniper twigs
           \               /
            ------||-------

Of course, any filter will do. The 20 kg batch fits well on a 40 cm x 150 cm filter consisting of a layer of juniper twigs. About 3-5 cm layer of junipers is thick enough.

Boil the junipers for a while before laying them to the filter. Put the mash to the juniper filter. Allow to filter, rinse with boiling water to add to the required volume of the wort. 40-50 liters of wort gives fairly good sahti. Allow to filter. Boil the wort for a while. Filter the wort again through the juniper-mash filter, rinse with boiling water.

The wort is ready.

Fermenting

Allow the wort to cool to the room temperature. Start the yeast in a smaller container (e.g. a couple of liters). Pour the starter to the wort. Allow to stay at room temperature overnight to start the fermentation properly. Transfer the container to a cold place (~ 8-12 C) for the main fermentation. Allow to ferment for 2 weeks. After that it is about ready to taste. It can be further cooled to lengthen the storing time. Sahti will not preserve for a long time. A month is about the maximum. This is perhaps the main reason why sahti is usually brewed for some parties. Notice that sahti is kept all the time in a non-sealed container, hence it will not get carbonated at all.

Variations

The juniper taste can be strengthened by using juniper's boiling water to the mashing. This is quite a usual routine, but it gives quite a strong juniper taste and most people will dislike it until they get used to it. To remove the juniper taste one can use something else as a filter. Straws are the traditional alternative to juniper twigs.

The less water in the wort, the stronger sahti. Also, the first wort to come out of the filter can be used to produce stronger sahti, the rest to produce thinner sahti. The more important party the stronger sahti, the more important drinkers the stronger sahti. A not-so-strong sahti is usually called "naistensahti", women's sahti.

The amount of rye can be varied. E.g. 20 % instead of the above 10 % would give a bit stronger rye taste.

The yeast used can affect on the taste. The Finnish baking yeast is quite effective and it will give quite a sour taste. I don't know how beer yeasts will do. I believe that those would do well. Anyway the sourness is quite characteristic for sahti.

All instructions given above are approximate. I would myself consider it dull to make beer or sahti using same recipe (or any accurate recipe) every time. Perhaps other Finnish readers of this news-group (or HBD) could give some other sahti recipes.

Sauna and sahti

I was also asked about suggestions how to use sauna in brewing. A warm sauna (60-70 C) is an excellent place to mash since it is easy to keep the mash at desired temperature however long you want to. Besides, sauna has been traditionally considered as the cleanest place of a Finnish household.