Sahti 2023

Sahti

an introduction to a traditional Norse brew

HL Marcello Fornarius

for Summits A&S (Feb 18, 2023)

Introduction

The surviving tradition of farmhouse brewing in the Nordic countries traces its lineage from the primary way of brewing in Europe in the first millennium - before brewing became a profession and hops were introduced to the process. The modern drinks sahti, koduõlu, gotlandsdricke, maltøl, and kaimiškas from the area around the Baltic Sea are all examples of farmhouse ales - sahti is merely the most famous. My main resource for this project is Viking Age Brew: The Craft of Brewing Sahti Farmhouse Ale by Mika Laitinen (2019). 

Archeological evidence is scarce, because vessels made of wood and organic remnants like malt don’t survive well. However, the oldest evidence of fermented drinks is found in Scotland and dates back five thousand years. As of 1500 BCE, mixed brews started to spread across the Nordic area.  The fashioning of large wooden barrels is at least 2000 years old, and these wooden vats would have been more common and cost effective for non-professional brewers. Sahti also relies on the technology of malting, where germinated grains are dried for longer storage, and due to climate, northern malts would have been dried over fire. As the technology of wort boiling and hops spread across Europe, homebrewing diverged from professional brewing in the 13th Century, with the archaic brews only surviving in remote areas.

 Farmhouse ales can be brewed for everyday drinking with low alcohol content (AC), or for feasting with higher AC. Sahti is typically a feasting drink, with an AC from 5-9% which is similar to modern microbrews. 

Glossary

Lautering: the process where wort is drained from the mash

Malt: grains in which enzymes have been activated in order allow for fermentation

Mash: malt mixed with hot water

Sparge: rinse malt grains with clear water to get more malt sugar into the wort

Wort: malt-sugar filled liquid

Brewing Techniques

Historical Equipment: large wooden trough (kuurna) for lautering, stones and cauldron for heating water, wood cask for storage

Historical Ingredients: barley and rye malts, house yeast, juniper (Juniperus communis communis)

Historical Process: 

First, the malt would be made. Grain would be steeped in sacks in a body of water for a couple days, then germinated to small sprouts. To dry the germinated grain, it would be spread out on racks in a threshing and drying barn (riihi) or in the smoke sauna. This took a few days, and both the fire and the grains needed to be constantly monitored and turned regularly. 

Brewing took all day and into the next night. On the morning of the brew, stones were heated in the fire. The malt was moistened with lukewarm water, and later hot-to-touch water would be added, till it was porridge consistency. Then the hot stones were used to boil water, which was then added to the mash, now easy to stir. After a third rest, more hot stones were added to the mash and it was stirred vigorously. 

The kuurna, essentially a large, hollowed out log, was prepared with juniper and straw on the bottom of the vessel to create a filter over the tap. The mash was then set on top of the juniper branches, and once the first vat was empty, it was placed under the tap of the kuurna and the liquid was allowed to drain. This liquid is called wort. More hot water, which had been steeping with other juniper branches, was poured over the mash. The first, thicker run might be fermented separately to create the high AC feast ale, but more hot water would be added to create a second, thinner run with lower AC, for everyday drinking. 

The wort is then cooled, and yeast added - often yeast was saved as particles on a birch whisk from the last batch. About a day later, once the yeasty foam died down, the sahti was transferred to a wooden cask. The ale matured in the cask for a week or so, and then drunk all at once at the feast. 

Modern Adaptations

I have modern brewing equipment, and direct heat applied from a stove requires a slightly different handling of the wort. Instead of adding successively hotter water, all the water is added at once and the temperature slowly raised. Modern barley, rye, and yeast are all slightly different from period, and modern malting is commercialized and different as well. However, I still used a combination of barley and rye malts, and used the whole malts (instead of malt extract used in modern brewing). For yeast, I have used a commercially available kveik yeast, designed to mimic traditional farmhouse yeasts. I did not use any juniper in any of my batches thus far, though I did filter with blackberry canes on this batch. This is my third brew. 

Challenges 

One of the reasons I didn’t use any juniper is due to the process - it was primarily used as a filter and cleaning agent for the vats - and the taste was a side effect. Another is that the Nordic juniper is a different subspecies than the American, so even asking someone to bring me some from Central Oregon may not produce a good flavor. Some other modern sahti brewers forgo the juniper, and depending on the region of Scandinavia, different plants may have been used - Lithuanian raspberry canes was one example mentioned, which is the reason that I tried blackberry canes this time. 

A second challenge is brewing using whole malt. Modern brewing typically uses predominantly malt extract, which is pretty easy to add to boiling water, and a small amount of whole malt “tea.” The first time I made sahti, I tried to do a hybrid of the modern process and the period process and started with nearly dry malt in my mash kettle and ended up being unable to stir the malt and some of it burned! The resulting brew had a more bitter taste than usually desired for this ale, though the brew judges at Egil’s liked porters, and modern palates being adapted to bitter hops meant that many friends still really liked it.

Another complication of using whole malt that I ran into is that the amount used to make 5 gallons (the size of the brew bucket), doesn’t actually fit in my 7.5 gallon boil kettle. The second time I tried, I made a smaller batch to avoid 1) mess and dishes and 2) burning the malt again. This was the brew I had at 12th Night 2023. The third batch was a similar size, and I contained the malt in a brew bag, which made clean up and filtering much easier.

Sahti is also harder to brew in warmer weather, unless you have a good place to chill it. My first batch I cold conditioned in a larger cooler, adding a new bag of ice every couple days. I was lucky I had one large enough for several gallon jugs. I also had to burp the lids of the jugs frequently, since the airlocks didn’t fit in the cooler. The second and third batches, brewed in winter, were much easier to cold condition in the laundry room. 

Future ideas

In future batches, I’d like to see the result of using regular bakers’ yeast or sourdough starter versus the commercial brewing yeast. Also, it would be fun to do a more period process using the hot stone method for heating water, and maybe even find someone to make me a small kuurna to try filtering with different branches - I have blackberries in winter, but I would also like to try juniper.

Modern Recipe

For 3 gallons

9.3 lbs Vienna or Pilsner malt (I used Vienna)

3.2 lbs Munich malt

.8 lbs crystal rye malt

1 packet Kveik yeast

3.6 gallons of water (plus water for hot sparging)

Resource: 

Laitinen, Mika. Viking Age Brew: The Craft of Brewing Sahti Farmhouse Ale. Chicago Review Press, 2019. 

Pictures from brew day (2nd/3rd Jan 2023 and 3rd Feb 2023)