Does Kefir Go Bad?

Kefir is a type of cultured beverage made from fermented milk, yeast, and good bacteria. This dairy product is prized for its probiotic health benefits. Kefir has a creamy, sweetish-tart flavor mostly due to the fermented milk proteins. This product is often made with cow, goat or sheep milk. However, coconut, rice, and soy milk could be turned to kefir too! Does kefir go bad? Technically, this product has already gone bad due to fermentation.

However, the bacteria culture may die if the kefir has been stored improperly. One thing to remember when storing kefir is to keep it away from direct sunlight. The live culture is sensitive to heat and light. Light and heat exposure could affect the quality of the kefir.

does kefir go bad

Image used under Creative Commons from David Niergarth

The fact is, kefir could be stored for short periods of time but it is not advisable to store it for months on end. On its own, kefir will only last for a couple of days so consume the drink right away. If you cannot consume your supply right away, you need to store it properly to extend its shelf life without killing the live culture.

How to Store Kefir?

There are two ways to store kefir, you could either store it in the refrigerator or the freezer! Refrigeration is best for short-term storage and freezing for long-term storage.

Storing Kefir in the Refrigerator

For unopened packs or bottles of store-bought kefir, there is no need to transfer the product to a different container. Just place the kefir in the farthest corner of the fridge and you are done. On the other hand, if you are storing homemade kefir, you need to prepare several glass jars. Sterilize the glass jars with hot water and leave them to dry completely.

Pour the kefir grains into the clean jar but do not fill the container. Pour enough milk to cover the kefir grains completely. Screw the jar’s lid to seal, write the storage date with a marker then stick in the fridge. Keep the temperature at a steady 40° to 45° Fahrenheit for best results.

Storing Kefir in the Freezer

Yes, you can freeze the kefir for long-term storage but there are steps that you need to take to prevent the live culture from dying due to the freezing temperature. Since you can’t use glass bottles to store kefir, you’ll use resealable plastic bags or a rigid plastic container with an airtight lid.

Transfer the drink in your preferred container, making sure to leave a couple of inches of space so the liquid could expand as it freezes. If you are using resealable plastic bags, squeeze as much air as you can prior to sealing. If you are using a rigid plastic container, just seal the lid, making sure it won’t leak. Write the storage date then stick in the coldest corner of the freezer.

does kefir go bad

Image used under Creative Commons from David Niergarth

Shelf Life of Kefir

When kept at room temperature, an opened bottle or leftover kefir will only keep for a day or two. When kept in the refrigerator, kefir will keep for 2 to 3 weeks. When stored in the freezer, kefir will keep for 3 months, maybe more if the storage conditions are ideal. Do note that the longer you store kefir in the freezer, the higher the possibility of flavor changes. Our advice is to consume the product as soon as possible for optimal flavor!

How to Tell if Kefir Has Gone Bad?

Because kefir is naturally lumpy and sour-tasting, it is hard to tell for sure if it has gone bad.  You can tell that the kefir has gone bad when it starts changing color, from creamy white to greenish blue or orange.

The discoloration is caused by molds; throw the product at the first sign of mold growth. If you’re starting to see fuzzy growth on top of the kefir, it is no longer safe to drink.  Same thing goes for the aroma, if it starts smelling moldy or rancid, discard the product.


Kefir is one of the most nutritious beverages on the market because it is packed with good bacteria, antioxidants, and calcium. Does kefir go bad? Yes, it could go bad especially when it is left sitting at room temperature for too long. The product is quite delicate so it should be stored properly. On top of that, the symbiotic colony of bacteria and yeast are sensitive to sunlight so keep the drink away from direct sunlight.