If you’ve ever had buttermilk, you already know it’s not the same as regular cow’s milk taste-wise. Since it’s already a bit sour when it’s fresh (we’ll explain why soon), how do you know when it’s actually gone bad?
Buttermilk has a longer shelf life than cow’s milk and won’t go bad until several days past its expiration date when sealed. Once opened, buttermilk will stay fresh for around 14 days.
We’ll explain the best storage techniques for buttermilk, how to spot signs it’s gone bad, and more!

What is buttermilk?
Buttermilk is fermented cow’s milk, giving it a tangy flavor similar to yogurt. Traditionally, buttermilk was made by collecting the liquid that was left over after churning butter out of cultured cream.
However, these days buttermilk is typically made by adding a probiotic (healthy bacteria) to pasteurized and homogenized cow’s milk. These bacteria ferment the natural sugars in the milk, producing lactic acid as a byproduct, which gives buttermilk its tangy taste.
Buttermilk is fortified with vitamin D similar to regular milk, and it typically is available as low fat (1% milkfat).
Most buttermilk sold in stores is also called “cultured” buttermilk. Sweet cream buttermilk is less common and is made as a byproduct of butter making.
Buttermilk can be drunk plain, but it’s also a great option for cooking and baking.
What is the shelf life of buttermilk?
Buttermilk comes with a printed expiration or use-by date, which indicates its ideal freshness. Buttermilk lasts longer than regular milk because the lactic acid produced by fermentation helps thwart bacteria growth, so its printed expiration date is likely later than a container of regular cow’s milk packaged at the same time.
Buttermilk will last around 14 days once it’s been opened. If it’s sealed and unopened, it’ll likely last a few days past its expiration date.
You can pop buttermilk in the freezer for longer-term storage. If you freeze buttermilk, expect it to last around three months.
Buttermilk shelf life summary
Refrigerator – sealed | Refrigerator – opened | Frozen – opened or sealed | |
Buttermilk | Several days past the best-by or expiration date | 14 days (as long as it wasn’t opened past the best-by date) | Up to 3 months |
How long does buttermilk go bad after opening?
You can expect buttermilk to last around 14 days after you open it. It must be stored in the fridge at all times since it’s a perishable product.
Can you use buttermilk after its expiration date?
Buttermilk is likely fine to use past its expiration date if it’s been sealed. If it’s a week or more past the expiration date, it’s probably worth replacing the buttermilk with a fresh container, though.
If you open buttermilk past its expiration date, try to use it in the next couple of days to ensure its flavor is ideal.
How to tell if buttermilk went bad
Consistency: Buttermilk should have a smooth, creamy texture similar to regular milk, but a little thicker. If you notice large clumps or the buttermilk is extremely thick as you pour it, it’s a sign it’s gone bad.
Smell: Buttermilk has a bit of a tangy smell even when it’s fresh due to the fermentation of the natural sugars. If it smells overly sour or off-putting, then it might be a sign of spoilage. (Tip: smell buttermilk when it’s fresh if you’re not used to it – that way you have something to compare it to smell-wise!)
Taste: Buttermilk has a buttery, slightly tangy taste. If it’s overly sour compared to how it tastes fresh, then it’s likely gone bad.
What’s the danger in using buttermilk after it’s gone bad?
Drinking a small amount of buttermilk after it’s gone bad won’t likely cause any major issues. If you happen to drink a large amount of spoiled buttermilk before realizing it’s past its prime, then you might be dealing with some unpleasant stomach symptoms for a day or two.
Best storage practices for buttermilk
- Always keep buttermilk refrigerated, ideally between 33-38 degrees Fahrenheit.
- Keep containers of buttermilk tightly sealed at all times to prevent oxygen from entering, which spoils milk faster.
- Avoid storing buttermilk at room temperature for longer than two hours. If it’s been longer than two hours, bacterial growth can increase and cause premature spoilage.
- Shake buttermilk well before using it.
FAQs:
If some separation has occurred and the buttermilk isn’t spoiled, you can whisk it to redistribute the clumps back into the liquid. If there are large clumps that aren’t easily whisked away, then it could be a sign that the buttermilk has gone bad.
Conventional buttermilk is fermented with beneficial bacteria, so it’s considered a fermented food. Fermented foods are known for their positive impact on digestive health and other aspects of health.
Leave a Comment