How Long Is Kefir Good For Once It's Opened?
Kefir, a fermented milk beverage that may look a bit like yogurt, has a relatively short shelf life after the seal is broken. Once open, it only lasts for up to five days, assuming you've put it in a sealed container in the fridge. That short lifespan has to do with a lack of preservatives in the liquid. Meanwhile, the mix of bacteria that's good for your gut health might also be a bit too hospitable for less-friendly microorganisms.
As with so many foods, exposure to air and light, frequent handling, temperature swings, and even the type of container kefir is stored in all influence its longevity. To keep kefir as long as possible, store it in a refrigerator at or below 40 degrees Fahrenheit. Place it toward the back of your fridge, where your appliance stays coldest and it will be hit with less light. Try to keep kefir in its original container but, if you do change it out, be sure the new vessel is clean and has an airtight seal.
Another option is to freeze kefir. Kept in the freezer, the fermented milk can last up to two months. Be mindful that the texture will change slightly when thawed (and, for food safety's sake, please thaw it slowly in the fridge and not on the counter at room temperature).
How to known when kefir has gone bad
With its tart flavor, one might wonder how to tell when kefir has spoiled. First, pour a glass and look at it. Does it look a bit watery compared to its previous form? Not a great sign. Now, give it a sniff. Does it smell especially sour? If it does, be safe and toss it. Other changes you might notice are a difference in color or mold, curdling, or a strange flavor. If you have any of these signs or are ever unsure, go ahead and dump the beverage.
If you're wondering what to do with excess kefir besides freezing it, whip up a smoothie. Another option is to use it like yogurt, mayonnaise, sour cream, or even buttermilk to add a little zest to your favorite dishes that already use dairy in the mix. Kefir can also be used in marinades, dressings, and even waffle or pancake batter.