Looks great!
In case you haven’t done a lot of research on sahti, there’s a few ways it’s treated differently than normal beer.
The yeast often used is “fresh yeast” which can be hard to find depending on where you live. It comes in bricks like little sticks of butter, and it has the consistency of modeling clay. It’s normally used for baking, which is why the recipe calls for baking yeast. It can give flavors somewhat like hefeweizen yeast. In the US, I was able to find that kind of yeast in a Latino grocery store, but I can’t say for certain if it was anything like finnish fresh yeast.
It’s normally drunk really young, by some people, even before it’s done fermenting.
It’s also typically not very carbonated.
One day I’m going to build a proper setup to do the traditional mash/lauter.
I looked it up, and apparently it’s also called either “cake yeast” or “compressed yeast”. I baked some rolls with it, if I remember right, and you could definitely taste it (which I liked, but some people probably want a “cleaner” taste).
Looks like there are some ways to get it in the UK. I have no clue if the genetics would be similar to what I can get, or what they use in finland.
https://www.forgebakehouse.co.uk/products/fresh-yeast-100g
https://www.shipton-mill.com/products/organic-fresh-yeast