How to know when buttermilk is over the hill?

[CathyA]

I needed to use my buttermilk to make some ranch dressing the other day, when I realized my buttermilk was like 2 weeks expired. It smelled just like buttermilk should.
I used it and we didn't get sick. I want to use more of it today.
How can you tell when buttermilk is bad??

[Blackdog Lin]

I have an iron constitution, and frequently use outdated foodstuffs. But my personal rule-of-thumb with buttermilk, assuming it still smells right, is: pretty much anything up to curdles and I'll use it. Any bits of curds, out it goes.

I like keeping buttermilk on hand, but like you, it's sometimes difficult to think of ways to get it all used up before expiring.

[CathyA]

Thanks Blackdog Lin,
I'll look for those curds.