Do Kefir Grains Float?

I remember the first times I made kefir I’d check in on my grains every few hours to see if anything had happened. To my surprise the grains started floating to the top after just a couple hours and I wondered if I’d done something wrong. Do kefir grains float?

Milk kefir grains naturally float to the top just before the milk separates into whey and curds. Water kefir grains usually do not float. If water kefir grains float it can be a sign that they are no longer good.

Making kefir essentially can as simple or as complicated as you want it to be. To spare you some trouble, I’ve collected all the information I could find on floating kefir grains right here in this post!

Kefir TypeShould FloatReason
Milk KefirYesMilk Separation
Water KefirNoGrains Are Dead
Do Kefir Grains Float

We’ll cover if kefir grains should float, why they float, and how to check if your floating grains have perhaps died.

Should kefir grains float?

Milk kefir grains should float, water kefir grains should not. That’s the simple rule to keep in mind. There are just a few exceptions to this which I’ll go over in the next section.

I have divided each sub-section into information about floating milk kefir and water kefir grains so it’s easier to find exactly what you are looking for. We’ll start with milk kefir grains since their reason for floating is usually quite simple and common.

Milk Kefir Grains

It is completely normal for milk kefir grains to float to the top of the milk during the fermentation process. As the Lactobacilli break down lactose into lactic acid carbon dioxide is released as a byproduct.

This carbon dioxide not only creates a fizzy taste (Read: Why is kefir fizzy?) in kefir but can also propel the kefir grains to the top. Typically this will occur anywhere between 12-18 hours after the grains have been set into milk.

Water Kefir Grains

When water kefir grains float to the top it’s usually not a good sign. Most likely they are no longer viable to use and have died. However, it also simply might be a sign that you used too much sugar in the beginning.

I’ll cover later how to check if your water kefir grains are actually dead or not but for now a quick fix would be to shake or stir your fermentation vessel lightly and see if there are any bubbles forming. If so, your water kefir grains are likely fine and simply cannot digest more sucrose.

Why do kefir grains float?

Kefir grains usually float because the carbon dioxide that has been produced during fermentation propelled the grains to the surface. But, there is also a myriad of other reasons why your kefir grains might be floating.

Here are the most common ones:

  • Too much sugar: One simple reason that kefir grains float is simply that there is too much sugar in the liquid that the microorganism is no longer able to efficiently break down. You can try using milk that’s lower in lactose for milk kefir or using less sugar to start your water kefir.
  • High temperatures: When temperatures get too high (i.e. if the jar is placed near the heater or in direct sunlight) kefir grains might also float to the top. The heat accelerates the fermentation process and can lead kefir grains to float before all of the sugars (lactose or sucrose) have been digested completely.
  • A lot of movement: Frequent stirring or shaking of the fermentation jar can also upset the symbiotic balance of yeast and bacteria and cause your kefir grains to float. For the best result keep your kefir in an environment with consistent conditions. Kefir grains are creatures of habit!

Milk Kefir Grains

Milk kefir grains will typically float because the carbon dioxide propels them to or because the milk curds have pushed the grains to the top. When kefir separates into whey and milk curds (Read: Why Kefir Separates) the whey settles on the bottom and curds form the top layer.

To avoid the yeast from overtaking the top part of the kefir jar you can try shaking it lightly two or three times. The whey and the curds should blend together again. Be careful not to shake your milk kefir too much or you risk over-fermenting it.

Water Kefir Grains

Water kefir grains float either because they are dead or because the organisms have eaten enough sugars and are now hanging out at the surface. Okay, let’s get more technical than that!

When most of the sugar has been digested and turned into acids (fermentation) by the bacteria culture effervescence is created. This allows the water kefir grains to attach to the tiny bubbles of carbon dioxide and float to the top.

However, more often than not, floating water kefir grains are not a good sign. In this next section, we’ll go over how you can check if your water kefir grains are just stuffed from a feast or actually no longer alive.

Are floating kefir grains dead?

Floating water kefir grains might in fact be dead. Milk kefir grains that float to the top are usually well and alive. But, in order to determine if your floating grains are actually dead, you’ll need to check a few things:

  • Shake or stir lightly: A simple way to check if your water kefir grains have already done some work in digesting the sugar is to give the fermentation vessel a light shake. If you see tiny bubbles emerge you know that your grains are fine. If not, continue down this list.
  • Separation into whey and curds: In milk kefir, the simplest way to check if your grains are dead is to look for the separation that occurs in fermented milk. Let your grains work for at least 24-48 hours. You should see the kefir clearly separating into a translucent bottom and creamy white top part. If not, your grains are likely dead.
  • Taste the liquid: The next step in checking if your kefir grains are still alive is to actually taste the fermented liquid. Does it taste slightly sour? Does it taste slightly fizzy? If the answer to both of those questions was no and you’ve given kefir enough time to ferment, the grains are probably dead.
  • Smell the vinegar: Kefir that has fermented correctly will have a very distinct smell. In the case of water kefir, it will smell a bit like vinegar and milk kefir will smell a bit like sour milk. If neither of these scents is presents it means that fermentation has not occurred and the kefir grains have not done their job.
  • Color/Texture: Lastly, we can look at the color and texture of the fermented liquid to determine if the kefir grains are alive and that the fermentation was successful. The color of fermented water kefir will depend on the type of sugar you used. White sugar should yield an opal color that is less translucent while brown sugar will yield a browner color. In milk kefir, look for the soil horizon-like texture in the milk curds (see picture below).
Alive Kefir Grains Texture
Alive Kefir Grains Texture


There is a vast difference between milk and water kefir in the floating behavior of their grains. For milk kefir grains it is completely natural to float near the milk’s surface while for water kefir grains it can be a bad sign.

Run through the checklist above to make sure that your kefir grains are alive and well before drinking the fermented liquid and setting up a new batch. Good luck with your fermenting 🙂


  • Hi, I'm Marvin! In early 2019 I started fermenting sauerkraut, kefir, and kombucha and noticed the incredible health benefits that came with it. I was less irritated, had fewer allergies and my skin got better. I started this blog to share how fermented foods have helped me and how simple they are to prepare! Look around and see what speaks to you and all the best on your fermentation journey!

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