I have tried without success to make Mozzarella using kefir to culture the cheese and drop the pH to about 5.2 but I have not had any success with this. How critical is the temperature at which I add the kefir (should it be about 50F)? I have added citric acid in tandem with the kefir but what seems to happen is that the milk curdles and the curds don't set - they tend to break up however gently I stir them. Making Mozzarella using only citric acid works fine.. but what is the cause of the incredibly fragile curds? Thanks