But this is the law that registered it, and you can see that it is "implicitly repealed". I'm definitely not up for reading a bunch of laws to find out exactly why right now

More interestingly, here's the description it has for making sahti:

Sahti is brewed by gradually adding water to the mixture of malt and cereals, starting at a temperature of around 40 C, which is increased to around 100 C by the time the last water is added. This is known as "mashing", and in some places this phase also includes boiling the mash. The heating times vary from short to a thorough boiling. Next, the wort is separated by straining in a trough or vat, and hops may be added. Traditionally, juniper twigs and rye straw are used for straining the wort, which is then fermented into sahti using baker’s or harvested yeast. Top fermentation is used. The main fermentation takes around three days at room temperature or cooler, after which the sahti is kept cool for at least one week. The alcohol comes exclusively from the sugar in the malts and other cereals.

"Baker's or harvested yeast" is presumably the relevant part here, as that seems to me to exclude cultivated brewing yeast. So on that basis I've done it wrong (and I plan to do some fining too, so doubly wrong), but since my stomach doesn't know any better I think I'll be safe from legal challenges

[–] tasankovasara@sopuli.xyz 3 points 1 month ago* (last edited 1 month ago)

Impressive research there!

I also did some googling. The production of this particular yeast was sold off to Canadian company Lallemand in 2007. It is still made at the Polttimo facility in Lahti, Finland, where Viking Malt products are also made. And this is the actual product. I use half a pack (25 g) for 21 L of beverage.

There are Sahti brewing competitions locally and an annual Finnish championship too. To participate, one does not need to employ the traditional mashing procedure. I understand the yeast has got to be that particular stuff though. It gives the brew a banana-like sweetness.