I love making buttermilk pancakes but I can never seem to use up my buttermilk before it passes the expiration date. The thing is, if I take a solid whiff of the "expired" buttermilk it smells great (even up to a month after the expire date).

How can I tell if it's still ok to use?

  • I experience the same problem, so I substitute evaporated milk mixed with a bit of lemon juice or vinegar. See my "buttermilk" pancake recipe here: justrightmenus.com/recipe.php?id=10 I make the pancakes with the substitute every time. Commented Jul 17, 2010 at 13:06
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    @JustRightMenus - I used that substitution for a long time. I switched to real buttermilk because, although the acidified milk has a similar texture, real buttermilk has a lot more flavor. Commented Nov 4, 2010 at 15:05
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    Personally I find the powdered stuff to be a better substitute than the mixing substitute, which flavor-wise I was not a fan of at all. America's Test Kitchen agrees with me that it is the best backup.
    – justkt
    Commented Nov 4, 2010 at 15:08
  • @justkt - I haven't used powdered buttermilk. Is it acidic or just the flavor? Commented Nov 4, 2010 at 16:01
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    @Sobachatina - it's the real thing - a powdered form of buttermilk itself plus a few other ingredients. Here's what I use: sacofoods.com/culteredbuttermilkblend.html
    – justkt
    Commented Nov 4, 2010 at 16:09

7 Answers 7


Buttermilk is already thoroughly packed with live bacteria. During its manufacture, that bacteria already consumed some portion of the available lactose and turned it into lactic acid.

Because of the lack of food, acidity, and the extreme competition it is pretty hard for buttermilk to go bad. The good bacteria will stay active and the buttermilk will get thicker and more sour until it runs out of lactose. In fact- when your buttermilk container has about 1/2 cup left you can make more just by refilling the container with milk and leaving it to ferment on the counter for a day. If you use it up more quickly than the bacteria eat the lactose then you can keep this up indefinitely.

Don't worry if it is thicker- if it still smells good then it probably is. As Noctrine said- mold around the lip is the worst risk. I am not a food chemist and despite my personal experience- if you ever suspect that food is bad just throw it out. $2 of buttermilk isn't worth an unpleasant afternoon.

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    I was curious about the ability to culture more on your own, and found a great reference from a professor of biology & chemistry: biology.clc.uc.edu/fankhauser/cheese/buttermilk.htm
    – ken
    Commented Mar 1, 2015 at 7:18
  • @ken- Dr. Fankhouser's site is a great resource for all sorts of home milk fermentation. Commented Mar 2, 2015 at 15:31

The only time I ever throw buttermilk out is if it has mold in it. I keep it in the back top shelf of the fridge and it does fine. I have some right now with an expiry date of Dec 2012. Whenever I'm making a choc cake or cornbread I open it and if it has no green, Shake it up to incorporate and go ahead and use it. I try to buy the kind in a plastic container, it seems to last longer (like 9 months isn't long enough LOL)


As long as it's mostly liquid, you're probably ok...Buttermilk tends to turn pretty solid when it goes bad. Still, I'd be scared of using it more than 7-10 days after expiration.

A good trick is to freeze it in the quantities that you typically use, and thaw as needed.

  • Do you just thaw it in a container. How do you defrost it... just leave it in the fridge, on the counter or...
    – Kyra
    Commented Jul 27, 2010 at 16:48

Buttermilk should hold for sometime after the expiry date, in general you should be wary if it has become chunky, and of course (like all food) if it becomes molded.

I've also ran across a few things that said it would have a taste that is more bitter than usual the worse off it becomes.


Buttermilk never expires. Ten days after the expiration date, just boil it for a few minutes and let it settle for a while. It makes a great dry yogurt in the form of cookies. They last for years.


I freeze left over buttermilk in ice cube trays. When frozen, I put the cubes in a plastic bag to be kept in the freezer & use as needed.

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    Could you expand on this? Presumably the buttermilk will keep in the freezer indefinitely (i.e., it won't "go bad" as long as your freezer is working and kept at a cold enough temperature), but do you thaw it in the fridge? Microwave? Does the texture suffer at all?
    – Laura
    Commented Sep 26, 2012 at 20:16

I also have a plastic container of buttermilk in the back of my frig cause it's coldest there for some reason and my expired in nov and it stills smells like buttermilk . I just shake it up before using , do the sniff test, and ck for mold and chunky texture if it's all good then I'm baking . Today I will be making banana bread 😃 Happy cooking

  • You typically want to check for mold before you shake it up. (see mommyoftwinz's answer)
    – Joe
    Commented Jan 7, 2015 at 15:40

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