Oh wow, where do you teach folk dancing? I used to go to some folk dancing lessons (Helsingin Pitäjän Kansantanssijat) but I'm living too far from them now, so I've had to give up dancing at least temporarily until I find a new group.
About my sources - sorry but I have little to point you to. I'm an enthusiastic collector of old cookbooks and kitchen crafts books (as they had larger scopes back then), so I've just read them and noticed what kind of recipes they include or don't include. Any books before commercial cheese making don't seem to include finnish hard (aged) cheese, even by mention or as ingredient in other recipes.
I remember reading somewhere (probably newer material) that it was forbidden in Finland to use the flesh coming from calves that were still milk-fed, so that's probably why no rennet could be produced. I understood that it's about the cruelty of butchering the calf while it's still milk-fed and a person eating that would be tainted by the cruelty.
Well, as you see, I'm obviously completely useless what comes to naming sources (hence my expression "I believe" in my last message).
The only thing I've found about european cheese coming to finland is discussed here:
http://www.yle.fi/java/elearning2/lesson/index.nvl?0.task=3563I know, it's ridiculously little information, and not from a reliable source.
Also, the Q&A of museum Sarka handle this topic:
http://www.sarka.fi/kuukaudenesine.asp?yv=9&av=88&esid=2&kieli=1This seems to be contrary to my information, since they specifically mention rennet.
However, I don't know what to believe, because my recipes for "Kehäjuusto" mentioned there don't include rennet, but are fresh buttermilk-coagulated cheeses (with or without eggs). I wonder if their information comes from Europe anyway... maybe I should contact Sarka for more information.
Maybe it's just that rennet was very rare for the above mentioned reason... Sarka mentions that the rennet was only taken from calves that had to be put off anyway... maybe for other reasons than getting meat?
About making Leipäjuusto without rennet - doesn't colostrum include the rennet enzymes by itself, so therefore it can be used in regular cheese making without rennet? Only it tastes really really different, so it's impossible to get the same taste using milk+rennet. I would try it but also don't have the financial resources.
Just waiting to get my cow...