Most of us would be better off if we consumed more probiotics. And that’s probably why you decided to try drinking kefir in the first place, right? This dairy drink is most known for containing lots of probiotics, and the health benefits they provide.
But as a fermented product, it’s not always clear how to tell if kefir is spoiled or not, or how long you can keep it in storage. That’s where this article comes in. In it, we go through all the basic storage-related information regarding kefir. We’ll talk about spoiled kefir and how to tell if yours is okay or not, the shelf life of this dairy product, and how you should go about storing it.
If you’re new to kefir and would like to learn a bit more than what’s on the label of a kefir bottle, this article is for you. Please note that I won’t be covering making homemade kefir, as there are dozens of great resources on this topic on the Internet. Besides, most people coming here will be people who bought kefir in the supermarket, not people interested in making it on their own. With that in mind, let’s start by talking about kefir going bad.
Can Kefir Go Bad? How To Tell If Kefir Is Bad?
For starters, I want to reiterate that kefir is a fermented milk drink ([WIKI]), and as such, it has all the characteristics of other fermented products, like sauerkraut or kombucha. That means its taste, texture, and the amount of fizz will be different from batch to batch, and also change depending on the season ([LW]). So the fact that this bottle doesn’t taste or feel exactly like the other bottle from the same producer doesn’t mean it’s spoiled. Kefir is an alive and active product, and every bottle is somewhat unique.
When it comes to signs of kefir that’s gone off, there are a few possibilities. The first and most obvious is the presence of mold on top of the kefir ([YK]). It might be a noticeable fuzzy growth, or just a few pink or orange spots here and there. While I read about people who just scoop the moldy part and consume the rest, I definitely don’t recommend it. If it’s moldy, just discard it. Same thing if for some reason your kefir has separated entirely or smells off.
Another reason for getting rid of the kefir is when it turns too sour. As a living product, kefir becomes stronger in taste and potency over time ([CG]). And at a certain point, you will probably find it’s too much for your taste buds. If that’s the case, you can either discard it or perhaps try using it in a recipe where that flavor will fit right in. Just to make it clear, overly sour kefir is perfectly safe to consume, maybe just not the most taste-buds-friendly.
How Long Does Kefir Last?
Like with all fermented foods, this one is tricky. One way to go about it is to assume that it doesn’t go off ([CG]), and throw it out once the taste is too strong, or it actually spoils. But it’s okay if you’re not super comfortable with that approach, as it’s not the only option available.
You can also go about it the more traditional way by observing the date printed on the label. Since kefir is a fermented food, treat that date as an indicator of how long the taste of the dairy drink will be optimal. So the perfect storage time should be around two to three weeks, and once kefir has passed its date, sooner or later its taste will become too strong. When will that happen, you ask? There’s no way of telling you the specific period, but you can safely assume that it shouldn’t be that bad even after a week past its date. That period will, of course, vary from batch to batch, and from person to person, as some people will find it sour much quicker than others. If the kefir is “expired,” make sure you check for all described signs of spoilage before consuming it.
Once you open the package, the shelf life doesn’t really change ([LW]), but there’s always a chance of microbial contamination causing the kefir to spoil. So it’s definitely not a given that the kefir you’ve opened 2 weeks before its date will last up to that date in top-notch quality. Like with similar dairy products such as buttermilk or sour cream, it’s best to consume this fermented milk drink as soon as possible.
How To Store Kefir?
You should keep kefir in the fridge, plain and simple. Refrigeration keeps it safe for consumption, but also prevents the fermentation from accelerating. And that quite a long shelf life I talked about in the previous section is due to the fermentation going slowly and steadily.
Once you open the container, you should make sure the leftovers are sealed tightly. If the kefir comes in a bottle or a resealable carton, that’s not an issue. But if it comes in a non-resealable plastic container, it’s probably best to pour the leftovers to a mason jar, especially if you expect to keep them around for a few days. Alternatively, aluminum or plastic wrap and a rubber band is a decent makeshift solution to the issue.
But what if you’d like to keep kefir for longer? While it has a quite long shelf life, if you have much more on hand than you need, you could use an extra couple of weeks of storage time, right?
Can You Freeze Kefir?
Freezing kefir, same as freezing yogurt, is somewhat tricky. If you were to freeze the whole container, the solids would separate from the liquid after thawing, and stirring and running it through a blender wouldn’t fully reconstitute it. To reduce this effect, try freezing it using an ice cube tray ([LW]). Pour the liquid into the tray, freeze the cubes, and transfer them to a freezer bag once rock solid. You will probably need to blend it after thawing either way, but the effects should be better.
Nevertheless, some of kefir’s creamy consistency will be lost in the process ([LW]). That means you probably won’t enjoy drinking that kefir on its own. But using it for a smoothie, or in a cooked recipe should work just fine. The loss of creaminess won’t be as noticeable in such a dish, as other flavors will take over, and everything should blend together just fine. Please note that in some recipes the frozen and thawed kefir might not work as well as in others, so it’s best to run a test before making a big batch.
Last but not least, when it comes to the question of whether or not the probiotics survive the freezing, it’s difficult to tell. Chances are some of them will become dormant when frozen and active again once thawed, but I didn’t find any legitimate research or tests on this subject. In other words, if what you care about the most when drinking kefir is your health, do your best to drink it fresh.
In a Nutshell
- Kefir is a living product and varies in taste, consistency, and the amount of fizz in every bottle. Slightly different flavor or mouthfeel doesn’t mean it’s spoiled.
- If there’s mold on the surface, the dairy product smells terrible or has completely separated, throw it out. If it’s super sour, it’s safe for consumption, but feel free to discard it if it’s too much for your palate.
- Keep kefir refrigerated, and always appropriately sealed.
- Frozen and thawed kefir works well in smoothies and cooked dishes but not doesn’t taste that well on its own. Freeze in an ice cube tray and stir or blend after thawing.