This is the second time I've seen a tiny bit of separation and it really went too long at about 29 hours. If I remember correctly, I don't think we want it to separate so best to stop before it does. My grains are a week old now and I must have had about 1/2 pint of it. I think half of it was the creamy slime like they call it.
They're very prolific grains and I have increased the milk every day.