If you've got a carton sitting in your fridge and you're unsure what to do with it, knowing How To Tell If Buttermilk Is Bad can save your recipe (and your stomach). This quick guide walks you through the simple signs so you can confidently decide whether to use it or toss it.
Jump to:
- What is Buttermilk?
- Buttermilk Substitutions?
- What Should Buttermilk Smell Like?
- What Does Buttermilk Do In Recipes?
- Can You Drink Buttermilk?
- How to Store Buttermilk?
- How to Tell If Buttermilk is Bad?
- How Long is Buttermilk Good For?
- How Long is Buttermilk Good For After the Expiration Date?
- Expert Tips on How to Tell if Buttermilk is Bad
- Frequently Asked Questions
- More Related Articles
- How to Make Buttermilk Substitute?
Buttermilk is a tasty addition to buttermilk chocolate cake, orange buttermilk scones, fried chicken tenders, dressings, and more! It lasts a long time and has been used in recipes for generations, but sometimes you might want to know how to tell if buttermilk is bad!
What is Buttermilk?
Current-day buttermilk is fermented, cultured milk. It is a thicker-than-milk, slightly lumpy liquid.
Originally, buttermilk was made by beating heavy cream past the whipped cream stage to get butter. When butter forms, there is leftover liquid called buttermilk.
That liquid was then left out overnight to ferment naturally. Today's buttermilk has live cultures in it to help it ferment- similar to yogurt.
Buttermilk Substitutions?
Milk Substitution- Simply add 1 tbs of lemon juice or vinegar to a cup of milk, let it curdle a bit, then use in place of buttermilk!
Powdered Buttermilk- this is a shelf-stable powder that can be purchased online or at some grocery stores. Mix the powder with water, and voila, you have buttermilk you can use in recipes.
Sometimes you just need a little bit of buttermilk and don't want to have to buy a whole large carton- that's why it's nice to be able to use a quick substitute!
What Should Buttermilk Smell Like?
Buttermilk has a sharp, tangy, and slightly buttery smell. It should not smell super sour, but more like a mild vinegar.
What Does Buttermilk Do In Recipes?
The acidity from the fermentation of buttermilk helps balance out sweetness, activates baking soda in baked goods to produce fluffy batters, and breaks down proteins to give a softer crumb or tenderize meat.
Can You Drink Buttermilk?
Yes, people from all different cultures consider buttermilk a standalone drink. I distinctly remember my own grandmother pouring a glass or two!
How to Store Buttermilk?
Buttermilk should be stored in the refrigerator in its original container. Before using, make sure to shake thoroughly since it can separate.
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Buttermilk can be frozen for up to 3 months. I like to freeze leftover buttermilk in cubes (using these trays), then store it in Ziploc baggies.
How to Tell If Buttermilk is Bad?
If buttermilk is extremely thick, coming out of the container in large lumps, and/or has a very sour smell, it is bad. There might even be some mold on the lid of the buttermilk or floating on top of it.
How Long is Buttermilk Good For?
An opened container of buttermilk will last 14 days in the refrigerator and can last slightly longer than its expiration date.
How Long is Buttermilk Good For After the Expiration Date?
Buttermilk is good for about a week past its expiration date if it has been kept refrigerated. This is due to fermentation in buttermilk, which allows it to last longer.
Always check buttermilk for freshness, even if it's not expired yet.
Expert Tips on How to Tell if Buttermilk is Bad
- Always give buttermilk a good shake before using - it naturally separates over time.
- Trust your senses - if anything seems off, it's better to toss it than risk it.
- Store buttermilk in the coldest part of your fridge, not the door, to extend freshness.
- Avoid drinking directly from the carton to prevent introducing bacteria.
- When in doubt, remember: mold or a truly foul smell means it's definitely time to throw it out.
Frequently Asked Questions
Look for obvious changes like mold, discoloration, or an off smell- these are the clearest indicators it's time to throw it out
Not necessarily - slight thickness or small lumps are normal, but large chunks or a slimy texture are signs of spoilage.
Fresh buttermilk has a tangy, slightly sour smell, but it shouldn't smell rotten or overly pungent.
If you notice yellowing, darkening, or visible mold, it's no longer safe to use.
Opened buttermilk typically lasts about 1-2 weeks when refrigerated, though it may vary depending on handling.
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How to Make Buttermilk Substitute?
Ingredients
- 1 tbs lemon juice or white vinegar
- 1 cup milk
Instructions
- Combine milk and lemon juice. Stir and allow to sit for 5-10 minutes until it curdles slightly.1 tbs lemon juice or white vinegar, 1 cup milk
- Once it is slightly thickened and lumpy use in a recipe as a 1:1 ratio for buttermilk.
Ford says
I have a jug of Kroger buttermilk from June of last year next to a pint that I bought yesterday. They look, smell and taste exactly the same. IMO the old one actually tastes better. Like liquid sour cream. My family has been baking with "old" buttermilk like this for years. The jug also doesn't look anything like these pictures. Maybe it's just that loaded with preservatives, who knows.
KmDunkel says
I agree. I use buttermilk months past its expired date, and it still smells fine and looks fine.
Susan says
I have tried this recipe and it works great.
Lisa says
Yay so glad it worked for you!
Mindy says
Hi! I regularly culture my own butter milk for baking/cooking only. I do also give a few tablespoons to my dog for her tummy. I refill my small container and let it sit out overnight. You can do this by leaving a small amount of buttermilk at the bottom of the carton and adding new regular milk to it. Shake it and set it on the counter. If you want to drink it, look up info on culturing yogurt. It’s basically the same thing, and this method would make sure you have the cultures correct for human consumption.
Lisa says
Oh that's neat!
Teresa DeMeyer says
My grandmother made her own Buttermilk. This was in the late 50’s early 60’s.
She had a lake cabin in Michigan and we would go there in the summer. Before we would get there ? (a few days) she would set out a carton of milk on the window sill and then after it soured she would make “Johnny Cakes” on a black iron pot belly stove. The only cooking means she had. They were so good. This just brought back all those memories.
Thanks
Terry
Lisa says
That sounds amazing! I feel like our grandparents did so much in cooking that we've lost today!
Constance says
That’s because they never wrote recipes down. 3/4 of my adult life has been spent trying to recreate some recipes. lol
Lisa Killian says
Yes I've learned the hard way with this too when trying to get family recipes together!
Donna L Holcombe says
I've recently learned that this substitution does not work for most gluten free flours. This explains what went wrong the last time I tried it.
Lisa says
Oh interesting, gluten free baking can be tricky for so many reasons! Hope you find something that works!
Satin says
Thank you for including photos in your explanation of what good and bad buttermilk looks like! They were especially helpful.
Lisa says
Yay! So glad I could help!