Milk, cream, butter?

[narwhal]

Hi all.  I'm a bit new at making cheese and this site has been a great help.  I'm looking at making my first Gouda this weekend, but I have a question about milk.  I use a pasteurized, non-homogenized whole milk to make my cheeses. I live in Canada, so our milk is sold in bags.  I give the bags a shake to mix up the milk and cream.  But I've noticed a couple times that the milk has "clumps" in it.  These clumps taste a lot like butter.  And I've noticed that when I heat the milk, depending on the cheese, it either melts and looks like oil bubbles or stays as yellowish clumps.  I notice most of this gets lost in the whey. 
So I'm wondering, do I initially heat the milk til the buttery clumps melt and gets incorporated into the cheese or do I just ignore it and heat the milk as per the cheese recipe?

I appreciate any comments.

[Bantams]

Unfortunately this is a common issue with pasteurized but not homogenized milk - it gets super thick clumpy cream on top, plus some butter globs.
The butter will always just melt out into liquid butter - no stopping that.
The cream should melt out into the milk and stay in suspension. I would give it a good shake and then try to reincorporate it as well as you can with a whisk while the milk is still cold. Then heat gently.
Also know that even when working with whole raw milk, it's normal (but annoying) for some butter to form simply from the action of pouring and stirring milk. It's definitely more common with Jerseys or similar (high fat milk with larger fat globules). 

[mikekchar]

I have found that the trick to reincorporating clumped cream is to warm the milk to 25 C and then to shake it until the clumps are gone.  You don't want to do it much higher than that because the membrane for the fat globules starts to break down at around 27 C IIRC (Note: my memory is notoriously bad, so you might want to check on that!).  I've been able to rescue milk that even had a 5 cm plug of cream at the top and it worked normally as far as I can tell.

[narwhal]

thank you muchly Bantams and mikechar, I will try out your suggestions next time.  I guess these issues are all part of making cheese.