I’ve been threatening to make a batch of not-yogurt and skip the crushed BioGaia tablet for one of the three cups to see if it made any difference.
Nope, no difference. I added yogurt from the previous batch and potato starch to the center cup, but no tablet. The other two cups got the additional tablet. They’re all equally thick, and they taste exactly the same.
So apparently the bacteria count in the yogurt is high enough that a tablespoon of the stuff is enough to seed the next cup. Given the happy result, I’ll probably just add the extra tablets every third or fourth batch.