How can you tell when buttermilk goes south?

[berkleybabe]

We want to use buttermilk in our fridge, but don't know if it's gone sour. (I mean, how can you tell?) Frankly, I loathe this stuff to taste so won't do it, but love it in on other things like baked goods.

Any insight here?

[kubasd]

when it starts saying y'all...

[jmcarthur8]

Sour buttermilk smells spoiled. Fresh buttermilk smells tangy, but it doesn't smell rank. Same with yogurt or sour cream.
I toss any of them if they have mold, but otherwise the expiration dates are mere suggestions to me as long as they smell fresh and tangy.

[ipsedixit]

Buttermilk will easily last a couple of weeks, if not more, past the "use by" date when refrigerated.

Buttermilk is cultured so it takes a long time for it to spoil, it just keeps getting more sour. I have used it for a few months past the use by date with no ill effects.

Unless it is moldy and/or completely separates, you should be fine, esp. for baking.

[Bacardi1]

Buttermilk is definitely one dairy product where I go by the stamped "use by" date.

[calmossimo]

That's interesting. Buttermilk is probably one of the dairy products where I am the most flexible when going by the use by date. I would much sooner toss milk or soft/semisoft cheese past its date than buttermilk, which I have successfully used for at least several weeks past the carton date with no ill effects.

See also:

http://chowhound.chow.com/topics/349176
http://chowhound.chow.com/topics/355842
http://chowhound.chow.com/topics/796895

[little big al]

Old joke...."How can you tell when yogurt's gone bad? Does it start to smell good?"

[todao]

Clearly, the sell by date isn't the exclusive governing factor, but it's a good place to start. If it's a week or two past the sell by date it's probably not going to taste fresh, even if it isn't spoiled. Our buttermilk is held at 36 degrees and it lasts far beyond the sell by date, provided it was fresh and properly stored when we purchased it. You can never tell how an item was handled before you took it home from the market.

[kengk]

Buttermilk and sweet milk both freeze very well. Neither of us drink either so that is what I do.

[todao]

Buttermilk that as "gone south" often tastes bitter. But your container should have a "use by" date stamped on it and that's a clue. You can also tell if it pours thicker than usual and smells somewhat "off" from what you'd normally expect.

[berkleybabe]

Thanks, think we're OK on the date.. but glad you know the taste of BAD buttermilk. Ick to drink, big time, but lovely in dressings and biscuits and rolls.

[todao]

I think you and I are in the same club. My wife likes it; I find it disgusting. I do use it in cooking but can't get it past my nose to drink it.