Scandinavia and the World

Comments #9727122:

Yogurt as far as the eye can see 31 1, 5:46am

Maybe pett is buttermilk, I am not sure. Pett is a subproduct. Sõir is a subproduct.
Hapupiim is an (over-)ripe product. Keefir and yoghurt are refined products.

There are different kinds of kohupiim. The bland or salted one is kodujuust. The ordinary one is simply kohupiim. There are also kohupiim with additives (vanilla, etc). And kohuke is kohupiim with chocolate exterior or kohupiim with jam interior.
The root of the word is k(u)ohu, such as kohutav (awful, a ruckus creating an uprising) or finnish 'kohtu' (a womb of a female, which incidentally sometimes also develops an uprising resulting in a birth) or 'kohustus' (a responsibility, something stemming or uprising from some other thing) or estonian 'kõht' (a belly).