I'd been having some trouble getting my yoghurt to set, although my process had not changed, and I was running out of my ideas. The only thing that I couldn't really control was ... the supermarket milk. Was some of it just ... not suitable?
Initial experiments suggest - yes. Batch N-1 was very runny. The taste was alright, but it didn't set. I got milk from my vegbox people (the excellent and recommended Riverford), and with the runny culture as a starter, it set like a champ.
@AspiringLuddite
Low fat or protein concentration?
Both claim to be just plain whole milk.
The supermarket house brand, of course, could come from anywhere, and since it was hit or miss, my hypothesis was that the milk from some of their providers was just ... not good for some reason.
@AspiringLuddite @Steveg58 i’ve heard cheesemakers say that ultra-pasteurized milk doesn’t make curds properly & you have to look for flash pasteurized instead—maybe its a similar issue?
@Satsuma @Steveg58
It's the randomness that's confusing - sometimes it works, sometimes it doesn't. I suppose that some of the dairies might UP while others don't, but ...
(And, for cheesemaking, UP milk doesn't work quite the same as other types for milk, but it can work. Unhomogenised is nice, when you can get it.)