Can You Drink Overfermented Kefir? (Milk Kefir)

In our previous articles, we talked more about the process of making kefir at your home. There, we mentioned a process called fermentation, where kefir grains are left in water or milk to ferment and form kefir, a probiotic beverage. But, many of you might not know that kefir can be consumed whenever you want after the fermentation. This means that overfermented kefir can definitely be consumed.

This further means that you don’t have to worry about leaving your kefir a bit longer than you should. The duration of the fermentation process can, however, alter the taste or the structure of your kefir, that’s definitely important to remember.

Let’s talk about fermentation a bit more. In this article, we are going to focus on milk kefir.


When is Kefir Ready?

Fermentation is all you need to make good kefir. Of course, putting in some milk or water alongside kefir grains is the first step. The first thing you’ll notice after the fermentation is over is that your milk becomes sort of a thin gel. It’s not very thick nor is it completely watery. The structure is resembling the yogurt. The interesting thing about the fermentation process is that kefir usually ferments from top to bottom. This means that the upper part of kefir in your jar can be fermented and the bottom part still has this watery structure.

In this case, kefir is far from fermented and should be kept for a few more hours. The bubbles inside the milk will start to form and get bigger, usually near the end of the process. When the bubbles reach the bottom of the jar, this process is finished. This is where YOU choose whether to consume it or not. In the so-called, underfermented state, the milk just started getting that gelatinous structure and there are a couple of bubbles forming. In this case, kefir is a bit watery. On the other hand, when the kefir is fully fermented, it’s tart and acidic, meaning that the separation is complete.

The best thing about kefir is that you can drink it in both cases – overfermented or underfermented.

The difference is in flavor. Those who often consume kefir tend to go for the golden middle. An overfermented kefir has an acidic flavor and is generally going to cause some trouble in terms of constipation. On the other hand, underfermented kefir is light on your stomach and might serve as a laxative. That’s why it’s best to try and go for the middle. It’s also the most delicious in this state.


What is the Condition for Fermentation Process?

To begin the fermentation process and to make your kefir last longer, there is a certain condition – the presence of real calories. We’re alluding to lactose-free milk and artificial sweeteners. Artificial sweeteners are known for the fact that they don’t have any calories. As its name suggests, an artificial sweetener is here to make a certain beverage or food sweeter but without adding some calories. Unfortunately, kefir isn’t able to survive in these conditions. Probiotics in kefir need to be fed, literally! And if you give them something with zero calories, that’s not going to work.

What about lactose-free milk, then? Well, due to the fact that it has enzyme lactase which helps to break down lactose sugars into glucose and galactose, we think that kefir might survive. Glucose is the primary source of energy for our muscles and brains, meaning that this easily digestible sugar might be a good option. Still, kefir should be made with ordinary milk, which is the verified way of making kefir. Since kefir interferes with lactose in a way that it helps break down these sugars, there’s no need for lactose-free milk.

This is one of the reasons why people who don’t tolerate lactose can safely drink kefir.


Fermentation with Raw Milk

If this is your first time reading about kefir, you already know that milk is an obligatory ingredient here. However, kefir can also be made with some raw milk. Contrary to what most people think, drinking your milk raw is the best way of consuming it. While it may be the best way, it’s certainly not the safest and drinking raw milk should be done on your own responsibility. This is why it’s very important that you find a reliable and verified source that takes care of its cows or goats and uses sanitary methods of making the milk safe.

Kefir made with raw milk will automatically have a better flavor, it will have more healthy bacteria, and more enzymes. During the boiling process, some key ingredients are removed or diminished in the milk. One of those is the protein. The boiling process reduces the protein’s biological value and slightly reduces its quality. Other components like enzymes and healthy natural bacteria are also sensitive to heat, which results in their elimination after boiling. Furthermore, the cream that floats on top of the milk is also lost in the pasteurization process. This cream is used for making whip cream, sour cream or butter.

Healthy raw milk is definitely much better than the boiled one. The effect of raw milk on our health is yet to be investigated but scientists proved that this boiling process takes away some of the best things about milk. On top of that, those who aren’t tolerant of lactose, digest the raw milk better. The important thing to mention is that we don’t advocate drinking raw milk and we don’t promote it. These are only the scientifically-backed facts and you should always get to know more about your source before you buy the milk.

Overall, kefir LOVES raw milk and works well as a combination. You can go for either cow or goat milk. Cow milk has a bit more fat, while the goat milk is nearly fat-free, depending on the source.


Overfermented Kefir and Reduced Lactose

After the kefir has been fermented, it can be left for two or three days before you consume it. The environment in which you should do it needs to be cold and dry, such as a fridge or the counter. In this case, the amount of lactose in kefir can be reduced and be replaced with a higher amount of acid and alcohol. Needless to say that kefir is already very low in lactose, so this process is almost redundant. Still, if you really want to further get rid of this sugar, you can do it. Just be ready to accept that the flavor will be different. Oh, and you’ll get a bit of alcohol here. You can’t get drunk by drinking kefir, though, so you’re still safe.

Aside from this effect, you can achieve another healthy effect by doing the exact same thing. You can increase the vitamin B, as well as the folic acid content. Furthermore, the flavor is improved due to the increase of the carbonation and alcohol content. When the kefir has fermented, strain the grains out, put on the lid, and let it stay there for another two or three days. This will make the kefir more acidic and the bottle will build up some pressure. Have no doubt that it can explode if you don’t open it once or twice a day, just to release a bit of pressure.


Despite having a bit less glucose and bit more alcohol, overfermented kefir is still a choice of many people out there. Overfermented kefir can definitely be consumed, although you’ll most likely prefer kefir that’s fermented enough to become consumable. When beginning the process of fermentation, it’s important to know that you need real calories and you should avoid artificial sweeteners at all costs.

The level of fermentation will greatly impact the structure, as well as the taste of kefir. That’s why you need to see what works best for you and stick with it. Both underfermented and overfermented kefir are safe to use, so you don’t have to worry about the health benefits of both.

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