Reducing Yeast Content in Kefir

Do you think that your kefir has become too yeasty? Read on to find out why you are probably right, and what you can do to reduce the amount of yeasts in your kefir.

. Like kombucha, kefir also contains yeast species. And today we are going to be talking about how to reduce this yeast content.

Before we get into how reduce yeasts in kefir – let’s just clear something up.

Yeasts are Not Bad!

The yeasts in kefir are not bad, or undesirable in any way. In fact, there has to be yeast present within kefir and its grains. This is because they play a crucial role in the fermentation process.

The only problem concerning yeasts is that they can become too much. Their levels can rise out of proper proportion and cause mild brewing problems within your kefir.

Let’s take a look.

Reasons Why You Might Need to Reduce the Yeast Content in Your Kefir

Overly Yeasty Kefir Does Not Taste Nice

First up, overly yeasty kefir does not taste great. It has that signature yeasty tang, and can also be quite bitter. Not nice. If you have been struggling with these types of tastes within your kefir, then this is most probably the problem. Your kefir has developed overly high levels of yeasts, and these are affecting the taste of the kefir.

Overly Yeast Kefir Will Ferment too Fast

If your kefir and its grains have developed high levels of yeasts, then your kefir will also begin to ferment quicker. It will mature and sour faster and faster as the yeast levels rise. While it might be nice not to have to wait long for your kefir to mature – overly fast fermented kefir will also not taste as good as a slow ferment. Slow ferments usually have milder and deep flavors, while faster kefir fermentations often yield kefir which is sharp, harsh and metallic tasting.

There is also a theory that if there is too much yeast present in your kefir – the resulting quick matured kefir will have less probiotic bacteria than if the kefir had a balanced amount of bacteria and yeasts. The reason behind this is that the yeasts have literally crowded out a portion of the bacteria. While the yeast species are also classified as probiotics, it is the bacteria which most people are after as far as probiotics are concerned.

Balanced Ferments Are Easier

As with kombucha, kefir SCOBYs / grains need to be kept in balance. This balance is just what we have been talking about, the balance between the yeasts and the bacteria. The yeasts and bacteria in kefir work in conjunction to ferment the kefir, and they are mutually inclusive when it comes to the health and stability of your kefir and its grains.

If your ferment has a balanced culture and the bacteria and yeasts are working in harmony, then you will have predictable and easy ferments with a minimum of fermentation problems.

6 Methods to Reduce the Yeasts in Your

As you can see, if the yeasts are too high in your kefir, then it is important to take some measures to lower them. Lowering the yeast levels will result in better, milder tasting kefir which ultimately will have fewer brewing problems and potentially more probiotic bacteria.

So, let’s take a look at six methods which you can use to lower yeast levels in your kefir.

# 1 Lower the Fermentation Temperature

If the temperatures are high, this can be a main cause of a ‘yeast overgrowth’ in your kefir. Kefir can be successfully made in a temperatures in between 65 – 70 degree. You can even go a little lower or higher than this range, depending on what your kefir grains are used to. However, if you are making kefir in temperatures at the upper end of this range, it is highly likely that the yeast levels will become high.

The reason for this is that yeasts thrive in a warmer temperature range than bacteria do. Which means that if temps are high, the yeasts will be basking, and the bacteria will be struggling a little. This then results in the yeasts multiplying, while the bacteria are usually just maintaining.

So, if you are fermenting your kefir in warm temperatures, then this is probably the number one change you should make to get rid of a lot of excessive yeast activity.

2 Ways to Lower the Fermentation Temperature for Your Kefir

There are two main ways you can lower the temperature for your fermenting kefir. Which one you choose will depend on by how much you need to lower the temperature.

# 1 Find a Naturally Cooler Brewing Spot

If you only need to lower the temperature a little to get to a medium range of temperature for your kefir, then the first thing you need to do is look for a slightly cooler place for your kefir to sit while it is fermenting.

Possible potential places to move your kefir to is into rooms which do not receive a lot of sunlight. Also, look for surfaces for the setting the jars / fermentation vessels onto which retain cold, such as stone slabs, tiles or granite tops.

# 2 Artificially Keep the Kefir Cool

If you need to lower the temperature for your kefir by more than a degree or two, then you will have to turn to an artificial method for keeping your kefir cool while it ferments.

Use a cooler box:

For this you will need a cooler box and some ice packs, or simply some plastic bottles filled with water. Freeze the ice packs / bottles of water. It is helpful to have a double set, as then you can swop them out when the working ones are defrosted once more.

Once the ice packs are frozen, pack them into your cooler box, allowing a space for the kefir to stand in.

Now simply replace the lid of the cooler box, leaving a small gap for airflow.

If you wish to monitor the temperature of your ‘kefir box’, you can place a minimum/maximum thermometer within. If the temperature has not dropped enough within the cooler box, you can up the amount of frozen ice packs. However if the temperature has dropped too low, reduce the amount of ice packs. You should be aiming for temperatures between 65 and 67 degrees.

Set Up a Small Designated Kefir Refrigerator:

In the instance that it is really super hot – all year round –  where you, live then you might want to consider the option of setting up a special refrigerator for your kefir.

If you wish to do this, you will have to purchase a temperature regulator and fit it to a small refrigerator. If you are not familiar with electrics of any kind, you may want to take this into an electrician to be fitted. Once fitted, you will be able to set your ‘kefir fridge’ to the exact temperature which you wish it to be.

The range of temperatures that refrigerators come with are too low for regular kefir making. However, if you purchase and fit a custom temperature regulator, this can allow you to set the fridge within the right range of temperature for kefir. You will probably want to use the smallest refrigerator that you can find for this. Unless of course you are making BIG batches of kefir. : ). In that case you would want the regular sized fridge!

This can be a great thing to set up if you need to cool your kefir all year round, and keep it down by quite a few degrees. However if you only need to lower the temperature of your fermenting kefir for the hottest few weeks of the year, then you can also simply go with the cooler box.

# 2 Use Raw Milk

Another common cause of high yeast kefir ferments can be heat treated milk. All milk which is not raw has been heat treated. Heat treated milk does not contain any bacteria. Which is good in the fact that the milk does not contain pathogens – the reason why most milk for sale is treated. However, what gets killed right along with any possible lurking pathogens, is a whole host of naturally occurring lactic acid bacteria in the milk. These are the same guys which are part of kefir and kefir grains.

If you choose to use raw milk, then you will automatically be injecting your kefir with a fresh dose of these lactic acid microbes every time you make a fresh batch of kefir.

If you have access to raw milk from a reliable source – then you can try out using this for your kefir. It will directly support and contribute to the bacteria populations within your kefir.

If however you can not source raw milk, then you can try the other methods, particularly number 5, which works on a similar concept (of introducing fresh bacteria into the kefir) as this method.

# 3 Do a Fermentation Cycle in the Fridge

Another trick you can try, is to do one fermentation cycle of your kefir in the fridge. The low temperatures in refrigerators are not suitable for fermenting your kefir at on a regular basis. However, one cycle at these low temperatures has the ability to trigger a quick yeast kill off. As mentioned above, yeasts do not do well at low temperatures. The bacteria within kefir on the other hand can survive them pretty well.

Once you have allowed the kefir to complete one fermentation cycle within the refrigerator, return to a normal fermentation routine. You should see that the yeast levels will have dropped.

# 4 Do 48-72 Hour Batches

One way to train your kefir to be more bacteria dominated rather than yeast dominated, is to start to do longer brewing cycles, 48 – 72 hours. In the beginning your kefir that you harvest will be quite tart and mature, probably more than you usually like.

However, if you keep at the longer fermentation cycles you should start to see a shift in the ratio of your kefir to bacteria strong, with less yeasty smells and yeast activity.

# 5 Soak Your Kefir Grains in Live Yoghurt

A great way to boost the bacterial community within your kefir – and thereby crowd out some of the yeasts – is to soak your kefir grains in a bowl of yoghurt.

You will need a bowl and some live, unpasteurized yogurt. Simply place your kefir grains into the yogurt and let them sit in there for up to four days at room temperature.

The reason why yogurt is so beneficial for giving kefir grains a ‘bacteria makeover’ is because while similar to kefir, yogurt is a bacteria dominated ferment. It contains the same set of bacteria that kefir does, but not usually any yeasts. When the kefir grains are exposed the yogurt for a few days, the abundant bacteria within the yogurt infiltrate the culture of the kefir grains giving them a bacteria boost. This in turn creates extra competition for the yeasts, meaning that they will decrease in number somewhat. And you end up with a more balanced culture!

# 6 Wash Your Kefir Grains

A quick way to reduce the yeasts in your kefir dramatically is to wash your kefir grains. While some people wash their grains every time they make a new batch of kefir – others never wash their grains. Many people say that washing your kefir grains is highly detrimental to them, can impact the success of your fermentation, and ultimately you might lose your cultures.

(In my personal experience this last advice is a little extreme. As I often wash my grains to reduce yeasty tones and they are in good shape.)

The reason why washing kefir grains can reduce yeasts is because washing has a direct impact on the surface of the grains. And the surface of kefir grains are where the yeasts are at! This is why washing your grains can drastically reduce the yeasts, and can be good for quickly fixing a yeast problem.

When washing you grains, try to use filtered or non-chlorinated water. This is the safest for the grains. Because chlorine is antibacterial, chlorinated water can have a negative impact on cultures.

If you use this method often like me, do be aware that you could be dropping the yeast levels too low. If this happens, you will probably notice that your kefir takes too long to culture. Struggles to fermented and seems to be on hiatus. If this happens – STOP washing and let the culture return to balance.

Final Word

And there you have it! As you can see there are a number of ways one can reduce yeasts in milk kefir. So, if you have been noticing overly yeasty notes in your kefir, there is lots that you can do.

Just be careful not to go totally overboard and remove too many of the yeasts. A word on that, if this does happen, do not worry. Just stop any yeast reducing activities, and allow things to even out again. Generally, the yeasts in kefir are more robust than the bacteria. This is particularly true if you are fermenting kefir under ‘yeast promoting’ conditions. Such as warm weather and heat treated milk.

If you guys have any questions or comments on this topic  – gives us a shout.

Daniela Klein

Writer and blogger, fermented foods advocate, unprofessional food photographer, intermittent garden worker.