buttermilk is bad

How to Tell if Buttermilk Is Bad – The Best Way

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Buttermilk is popularly used in baking and gives baked items a slightly tangy taste. Buttermilk is the run-off liquid found after churning butter and is now a cultured product rich in probiotics, calcium, potassium and phosphorous.

As it is commonly used in baking and not for much else, buttermilk is often left to sit in the refrigerator for an extended period of time.

If you have some buttermilk sitting in the fridge, how do you tell if it has gone bad? There are a few ways to tell if buttermilk has gone bad.

You can smell the buttermilk, observe the texture, have a taste, or check the expiration date. If anything seems off, there is a good chance that the buttermilk has spoiled and should be thrown away.

It can be tricky to tell if buttermilk is bad, especially if you are not used to using it at home, as it has a very different texture to milk and has a tangier smell as well, which many of us associate with off milk.

Below is everything you need to know on how to tell if buttermilk is bad, why buttermilk might go bad, and how to extend its shelf life.

The Signs That Buttermilk Is Off

There are a few signs to look for to see if buttermilk is off or not, so if you are not completely sure whether it is off or not, you can check for other signs to make a decision.


Using the different senses, here are a few signs to look for to tell is the buttermilk has spoiled.


Buttermilk does have a slightly tangier smell than normal milk or other dairy products, but the smell does tend to become sourer as the product spoils.

There is a period of buttermilk storage where it can be difficult to detect a particularly sour smell, but if it has gone properly sour, you will be able to detect it straight away.

Remember that a closed carton of buttermilk will have a stronger smell, as the odor has not had a chance to escape, so take that into account when smelling a newly opened buttermilk.

Buttermilk should still have a buttery, tangy smell, but not sour.


You can tell whether or not buttermilk has gone off by simply looking at it. When it spoils, buttermilk can have slight discoloration.

Buttermilk which is well past its expiry date might even have mold growing on the surface and around the lid.

This is due to increased bacterial growth, and if there is any mold present in the buttermilk or on the container, you should just discard it straight away, it is not worth any foodborne illnesses that come with drinking bacteria-ridden buttermilk.


One sure way to tell if buttermilk has spoiled is to look at the texture (and feel it if you’re brave enough).

When it begins to turn bad, buttermilk develops a thick, clumpy texture. It will be difficult to pour and there will be large clots. There is no way to salvage buttermilk that has turned lumpy, as there is a good chance that it is spoiled.

Take note that buttermilk does naturally have a small number of lumps, but this should not interfere with the way the buttermilk has been poured and the little clumps should break up when it is whisked and mixed in with other ingredients.


You might have missed the other signs of buttermilk being off, and taste might be the next option.

Buttermilk does have a slightly tangy taste, but if the buttermilk tastes sour or off in any way, it should be thrown away.

Buttermilk should also have a buttery taste, with a certain creaminess, and this also disappears once the buttermilk starts to spoil.

Expiration Date

A sure way to tell if your buttermilk has spoiled, if you are unsure whether looking at the other signs, is to look at the expiration date.

If you cannot tell if it is off by smelling, tasting and looking at the texture, and it is before the expiration date, it should be fine to use.

However, if it is a week past the expiration date, you should discard the buttermilk.

Buttermilk Is Bad – Why Does It Go Bad?

Like any other dairy product, buttermilk does eventually spoil. Buttermilk is high in lactic acid, which is hostile to harmful bacteria growth, however, this doesn’t last forever, and after a few weeks, the harmful bacteria begin to grow as the buttermilk continues to ferment and become more acidic.

buttermilk is bad

This bacteria growth is what causes the buttermilk to spoil, and makes it risky to drink after its expiry date as there is a higher chance of foodborne illnesses.

How Long Does Buttermilk Last?

All buttermilk will have a sell-by-date and an expiry date. It is important to note that you should still be able to use the buttermilk about a week past the sell-by date, but this also depends on how the buttermilk was stored and transported.

Once the buttermilk container is opened, the degradation of the product happens faster. It is best to finish a bottle of buttermilk within a week or two of being opened.

Once again, this is also dependent on how well the buttermilk is stored and if it has been contaminated with any other products.

Saco buttermilk

Whether opened or unopened, buttermilk needs to be kept in the fridge.

Tip: If you’d like buttermilk that lasts longer and doesn’t need to be placed in the fridge, you should consider powdered buttermilk. This one is the one my mom always used while I was growing up.

How to Extend the Shelf Life of Buttermilk 

Buttermilk needs to be kept refrigerated and not left out to sit at room temperature. If you are not planning on using the buttermilk straight away, rather leave it unopened, as an opened carton of buttermilk will not last as long as one that is unopened.

Practice good hygiene when using the buttermilk, keep your fingers away from the lid when you are pouring and never drink straight from the carton, as this could introduce bacteria to the buttermilk which could cause it to spoil faster.


I’d also suggest you use a quality Airtight container to store your buttermilk, which will help it last much longer.

If it’s liquid buttermilk, I would use these containers from Amazon, and if it’s powdered buttermilk, I’m completely obsessed with this set from Rubbermaid.

You also have the option to freeze buttermilk to further prolong its shelf life. Freezing will alter the consistency a bit and could lead to the buttermilk clumping a little and separating, so it is best not to use frozen buttermilk for drinking or uncooked recipes.

However, frozen buttermilk will still have its acidity content, which is what most people look for when using it to bake, as it assists in baked items rising.

Buttermilk can be kept in the freezer for up to 2 months, and while it will be fine to use after this, the quality will deteriorate rapidly.

Frozen buttermilk is also great to use to tenderize meat, where you leave the meat to marinate in the buttermilk overnight or for a few hours.

Keeping Buttermilk Fresher for Longer

If you don’t want to have to worry about whether or not your buttermilk has gone off, you should keep it refrigerated and use it within one to two weeks. If you need a longer shelf life, you can place the buttermilk in the freezer.

The best way to tell if your buttermilk has gone off is to smell it, look for any signs of spoiling, and check if the texture is too lumpy. If there are any signs of the buttermilk being off, you should throw it away.

Related Questions

What Is Powdered Buttermilk?

Powdered buttermilk is a good option if you do not use buttermilk too often, and you do not want to have to replace spoiled buttermilk in the fridge every couple of weeks.

Powdered buttermilk has a very long shelf life and can be kept at room temperature. You only need to make what you will need to use at one time, so there is no chance of wasting it. 

Powdered buttermilk is usually used in baking, and is not so suited for drinking. It will certainly not have the same taste and consistency as real buttermilk, but it is worth it if you don’t want any wastage.

Can I Use Expired Buttermilk?

Expired buttermilk is safe to use as long as it does not have a strong, unpleasant smell, if it is too thick to pour or if there is mold present.

You can use expired buttermilk to add to recipes that need to be cooked, such as pancakes, biscuits, and pies.

If the buttermilk has passed the expiry date but still seems fine otherwise, you can freeze it to use at a later stage, but it should not be refrozen after this.

Is Buttermilk Supposed to Be Lumpy?

Buttermilk does usually have some small lumps and clumps that can be stirred away, but if it becomes very chunky and you can’t pour it, then you should not use it.

How Can I Make Buttermilk Using Milk?

If you need some buttermilk but don’t have any, you can make your own using regular milk.

Add some distilled white vinegar or alternatively, you can use lemon juice, to the regular milk and leave it to sit for 10 minutes. This will thicken the milk and it can then be used in place of buttermilk.

I highly recommend this video by the Preppy Kitchen on YouTube. He shows you three different ways to make buttermilk by yourself at home.


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