How long does buttermilk last? (+5 ways to tell)

In this article, we will answer the question “How long does buttermilk last?”, and how to store buttermilk to extend its shelf life?

How long does buttermilk last?

Buttermilk will stay good for 1-2 weeks past the sell-by date. This is not to be confused with the expiration date. The shelf-life of the buttermilk largely depends on how it was handled and stored. After opening, if the buttermilk is not to be consumed within 1-2 weeks, it is best to freeze it.

Freezing extends the the-life of the buttermilk. It is better to use frozen buttermilk as soon as possible. Because after 3-6 months of frozen storage, buttermilk undergoes irreversible and undesirable textural changes. 

Buttermilk must be refrigerated at all times to ensure its safety and quality. The following table shows an estimate of the shelf-life of buttermilk under different storage conditions.

In the fridge 
Buttermilk (unopened) 1-2 weeks past the Sell-by date 
Buttermilk (opened)1-2 weeks

What is buttermilk’s expiration date? 

The expiration date of opened buttermilk is 14 days when kept refrigerated. Unopened buttermilk can last longer than 14 days.  In frozen form, buttermilk can last up to three months.

Cultured vs traditional buttermilk

Traditional buttermilk available at a farm differs in its composition as compared to the commercially packaged buttermilk. The process used to make buttermilk is similar to that of yogurt. In this process, bacterial cultures(Lactococcus lactis ssp. lactis) are added to skim milk along with salt and citric acid. This mixture is allowed to ferment for 14-16 hours. Milk sugars are converted into lactic acid. The lactic acid and diacetyl present in buttermilk impart a tangy and buttery flavor to the end product.

Traditional buttermilk, on the other hand, is a liquid by-product of butter; that is produced by churning the fat from milk cream. Traditional buttermilk has a less sour taste than its cultured counterpart. Cultured buttermilk is pasteurized at 161°F (71.7°C) for at least 15 seconds to kill harmful bacteria. Buying unpasteurized buttermilk should be avoided to avoid health risks.

How to tell if the buttermilk has gone bad?


Spoiled buttermilk will develop mold on the surface and near the lid of the container. Moreover, spoiled buttermilk undergoes discoloration and it is pretty obvious to tell.


Spoiled buttermilk will develop a large clump that will not be able to dissolve when whisked. Moreover, it will become too clumpy and thick to pour. Note that fresh buttermilk has small lumps naturally and it is not to be confused with spoilage.


Buttermilk should taste tangy with a creamy and buttery mouthfeel. However, if that is not the case and it tastes too sour, the buttermilk has gone bad.


If the buttermilk smells extra sour, it has gone bad. However, a newly opened container of buttermilk smells extra sour. Therefore, do not rely on the smell alone to detect spoilage.

Expiration date 

Buttermilk that is 1 week past its expiry should not be consumed. It has become unsafe and should be avoided to protect one’s health.

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How to store buttermilk to extend its shelf-life?

  • To extend the shelf-life of buttermilk, it is important to handle with using clean hands. Drinking directly from the buttermilk carton can introduce bacteria into the buttermilk that can lead to spoilage.
  • Do not place the buttermilk container in the fridge door because this area suffers the most temperature fluctuations. Ensure the storage of buttermilk at a steady temperature of 4.4°C.
  • After using, never place the buttermilk on the counter at room temperature. Put it back into the fridge immediately after pouring out the amount needed.
  • Switch to powdered buttermilk if you do not want to waste buttermilk to spoilage. Powdered buttermilk can be stored at room temperature and is suitable to use in baking.

Freezing buttermilk

Frozen buttermilk won’t have the desired texture to be used for drinking. It is recommended to use it in baking and for cooking. The acidity of the buttermilk stays intact and activates baking soda when used during baking. It can also be used for meat tenderizing.

Freeze the buttermilk by pouring it in the ice cube tray or in a container. Use a 1-inch headspace on top of the container to allow the buttermilk to expand.

What is buttermilk and why does it go bad?

A 250mL cup of buttermilk low-fat dairy product that provides about 8g of proteins. It can be used as a drink, converted into cheese, or added to sauces and dips for an enhanced flavor and creamy consistency. 

Bacterial growth to unacceptable levels is responsible for the spoilage of buttermilk. Buttermilk continues to ferment as a result of which, more and more acid is produced.


In this article, we answered the question “How long does buttermilk last?”, and how to store buttermilk to extend its shelf life?


Does Buttermilk Go Bad?