Thanks for all your help. The milk I buy from Horizon is marked "pasturized" vs. the UHT marked milk they also sell beside it. Same milk worked just fine for my mesophilic cheeses.
I used Calcium Choloride as called for in the recipe.
I've tried to contact New England Cheesemaking Supply (www.cheesemaking.com
) where I bought the kit, but e-mails bounce back and phone number isn't in service. I was thinking that maybe the culture had expired.
If you have any other ideas just let me know. In the meantime, I'll hold off on the thermophilics until I can get more cultures and test my theory.