Buttermilk vs Kefir | Benefits and why you should drink them

Buttermilk and milk kefir are both fermented dairy products. In the buttermilk versus kefir debate, they appear similar in their texture. Still, kefir is commonly thicker in consistency, closer to yogurt, than buttermilk which is thinner and closer to the liquidity of milk. Kefir is more intense with a sour and tangy flavor than buttermilk, which is milder in taste. In nutrition, Kefir milk tends to have higher protein content and is richer with gut-healing probiotics than buttermilk. On the other hand, buttermilk has a lower fat content than milk kefir which is good to remark if you are following your fat intake.

Two glasses side bu side, one filled with buttermilk one filled with kefir.

It is generally known that kefir and buttermilk like other fermented foods are good for your gut health. But what are the differences between kefir and buttermilk? How do they differ in nutrition, cooking, and storing?

So let’s dive deeper.

Keep in mind that the writer, that’s me, is not a doctor. Any health guidance or such in this post must be considered as a note only that refers to the sources and studies that I have used. The reader is responsible for his or her own health choices.

Always contact your doctor first before making any big changes to your diet.

Let’s start with some useful concepts in our FAQ section so you can easily keep up with our debate of buttermilk vs kefir.


What is the meaning of culturing? 

Culturing simply means that you have used a microbial starter to activate the fermentation process. In this starter, there are both bacteria and yeast present. For example, milk kefir needs milk kefir grains (a microbial starter) to turn milk into milk kefir.

What does fermenting mean?

Lactic acid fermentation or lacto-fermentation, is one type of wild fermentation. We need certain bacteria, like Lactobacillus, that are actually present in anything that grows in the earth. (Source.) So lactic acid fermentation uses bacteria to ferment the the food product with the help of sugar. Fermenting gives a sour flavor and increases the shelf-life of the product. Buttermilk is a fermented food product as sauerkraut is too.

What is lactose? 

Lactose is the natural milk sugar found in dairy products.

What is microbiota?

The human gut microbiota is the trillions of microbes, like bacteria, that live in our gut.  It is the complex collection of tiny microorganisms that affect our health deeply. If our gut microbiota is in balance we feel perfect. But when it is not we need to balance it with beneficial bacteria like the ones in fermented food products like kefir and buttermilk to stabilise the harmony. (Source). 

What are starter cultures?

A starter culture is a tiny quantity of yeast or bacteria that is added to the product to activate the process of fermentation. Starter cultures can be the lactic acid bacteria to start milk to turn into yogurt or buttermilk. Yeast is a starter culture too that you add to the bread to start the process that makes the bread rise.

What are probiotics and probiotic foods?

Probiotics are living microorganisms, good bacteria, that provide health to heal your gut microbiota and boost your immune system. Probiotic foods are fermented foods that we enjoy for the probiotic benefits like yogurt, kefir, buttermilk, sauerkraut, and kimchi. The most common probiotics we know are the Lactobacillus and Bifidobacteria. (Source).

A hand pouring kefir into the glass on a wooden surface.

Short on time?

Pin it for later!

The origin and production of buttermilk and kefir

Now that we know the key concepts in fermented and cultured products we can go through a bit of the background of buttermilk and the historic kefir.

Traditional buttermilk and modern buttermilk today

In the beginning, traditional buttermilk was a byproduct of butter. When churning butter the residual liquid is called buttermilk. Despite the name, buttermilk does not contain any butter. Nowadays modern buttermilk has nothing to do with butter for it is made with lactic acid bacteria that are introduced to a bucket of low-fat milk, and the rest is history. 

Modern buttermilk is a fermented dairy product. The shop-bought ones have been pasteurized and homogenized, and different bacteria cultures have been added in, like Lactobacillus bulgaricus and Lactococcus lactis (source).

The origin of the historical milk kefir

Kefir is fermented too, but with kefir grains. Kefir grains do have lactic acid bacteria, but they contain also some yeast. The grains are symbiotic colonies of bacteria and yeast (SCOBY). This symbiotic culture of bacteria activates in milk to create a tangy taste and sour flavor as a byproduct.

The kefir grains are quite historic ones for they have been around already for about 6000 years – that we know of. Because of the lack of a refrigerator, which was not invented until 1913, the nomadic people in the Caucasus Mountains (an area between Russia and Turkey) fermented fresh milk to increase its shelf life. And that was about 2000 years ago. (Source.) Nowadays kefir is quite popular in Russia, and that is the road how it got in here to Finland too.

The production of kefir, the fermented milk drink, is usually made with skimmed cow’s milk. According to recent findings, it can be made with other milk products like camel milk, goat milk, sheep milk, and even buffalo milk! (Source.) 

The differences in origin and production of buttermilk and kefir

Traditional buttermilk has its origins as a byproduct in butter churning while modern buttermilk is fermented with lactic acid bacteria. Kefir, on the other hand, is fermented with both bacteria and yeast that live in kefir grains. The origins of the grains are in the Caucasus Mountains, where nomadic people fermented their milk. Both drinks are fermented but in slightly different ways.

How buttermilk and kefir are done at home

How to make buttermilk at home

Buttermilk is easily done at home too. You need some regular milk (preferably with low fat content), and some buttermilk to start the fermentation process. Both should be at room temperature. Then you mix both and leave be about 24 hours up to 48 hours on the kitchen counter and then another 24 hours in the fridge. 

Another quicker option is to make the milk curdle with some acid like lemon juice or apple cider vinegar to create your own buttermilk in about ten minutes.

How to make kefir at home

You can make kefir at home when you add the milk kefir grains to the room temperature milk. Let the grains do their magic 24 hours on the kitchen counter before straining the grains out. Bottle the kefir and move it to the fridge. You can do milk kefir with a powdered starter too.

The interesting thing is that the kefir grains are born quite naturally. It is still being determined how kefir grains maintain their functionality indefinitely. So far no one has succeeded in producing the grains artificially. (Source.) So it means that the grains we are using now are direct descendants of the first kefir grains, which is amazing!  

Homemade buttermilk vs homemade kefir: the differences and cost

Both buttermilk and kefir can be made at home. Buttermilk is easier to start if you have it in your grocery store. You need always a bit of buttermilk to make new buttermilk which has both advantages and disadvantages. To make milk kefir you need the milk kefir grains to start it. The kefir grains cost about twenty times more than one liter of buttermilk. – so the starting price is remarkably higher. Now there’s a but. The kefir grains are yours forever and you do not need to buy them again if you store them right you can make milk kefir over and over again with just the price of the milk that you use as a raw material.

Taste and texture of buttermilk and kefir

A tiny paper written "buttermilk" on it, a tiny glass full of buttermilk and a spoon with spilled buttermilk on the wooden surface.

How does buttermilk taste and look like?

Buttermilk is thinner than kefir and has a creamier texture. To compare, it is still thicker than milk for example. It contains beneficial bacteria that make the texture thicker and slightly sour. Buttermilk has a somewhat tart taste and a rich tangy flavor.

The characteristics of kefir

Kefir milk is thicker than buttermilk but clearly more liquid than yogurt. Its tangy and acidic flavor level depends on the fermenting time. The longer time at room temperature – the deeper and more pungent flavor you get. Because of the yeast in kefir grains, the kefir is slightly bubbly due to the carbon dioxide forms in the fermentation process.

A tiny paper written "kefir" on it, a tiny glass full of kefir, and a spoon with spilled kefir on the wooden surface.

Buttermilk vs kefir: the key differences in taste and texture

Buttermilk is thinner than milk kefir in consistency. Kefir is tangier than a bit milder buttermilk. Kefir is a bit bubbly (because of the yeast in kefir grains) which is absent in buttermilk. Both are still sour, acidic, and tangy in flavor.

Storing and shelf life of buttermilk and kefir

Kefir in a glass jar and small glass filled with kefir on a wooden surface and a dark background.

How long buttermilk lasts and how to store it?

You can store buttermilk in the fridge for 1-2 weeks. When fresh (about 1-1,5 weeks) it is good to use in uncooked things like smoothies and dressings. For example, you can use it for cooking longer than in fresh, uncooked drinks. Shop-bought buttermilk stays good longer when it is closed than an opened one. Store in the back of the fridge where it’s colder than in front to increase the shelf life. In the freezer keep for up to 3 months.

How long kefir lasts and how to store it?

Homemade kefir lasts longer than a shop-bough one. It can last at room temperature for 1-2 days, in the fridge for 2-3 weeks, or even longer! (Source). You can freeze the kefir too for up to 3 months. Notice that when you freeze it the texture will suffer and I would suggest that you use it only in baking and cooking and not in uncooked portions like smoothies and such. 

If we are going on a vacation and I have some kefir or buttermilk still left, I will pour it into ice cube trays to freeze it easily to melt and use for pancakes or waffle batter.

The key points in storing buttermilk and kefir

Thanks to the fermentation both buttermilk and kefir can stay for 1-2 weeks in the fridge, kefir even one week longer. When needed they can be frozen for up to three months. Freezing affects the texture and they are better to use in cooking than fresh after melting. They do still have both their acidity and sour properties left.

When buttermilk and kefir are gone bad

When it is time to throw out the buttermilk

The texture of buttermilk gets thicker when it is older. If it is lumpy and too heavy to pour, you can assume it has gone bad. If buttermilk has visible mold or a distinctive strong sour odor, you should discard it.

A spoon with spilled buttermilk, a tiny glass with buttermilk, and a small paper with buttermilk written on it on a wooden surface.
A spoon with spilled kefir, a tiny glass with kefir, and a small paper with kefir written on it on a wooden surface.

When the kefir is bad, or is it?

If you see any mold of any color, or black spots or the milk starts to have a pink shade your kefir has gone bad. 

I had lately a shop-bought kefir carton in the fridge that was way past best before date, maybe more than a week. The kefir kept fermenting in the carton and it started to round on the edges. Looks scary, but when you open the cartoon it doesn’t explode like a shaken soda can – no worries. The over-fermented kefir was a bit tangier than normal but completely good still.

So use all your senses when evaluating the state of kefir.

No visible changes or mold of any kind. No alarming smell. How about the taste? If the taste is good too you are good to go.

When to discard and not to discard the buttermilk and kefir

Use your senses to decide the condition of both buttermilk and kefir. If you notice a clear odd and strong odor or you see visible mold it has been contaminated by bad bacteria and they should be discarded. Otherwise, many times the buttermilk as well as kefir just deepens the flavor after its best-before date but does not exactly go bad so quickly.

nutritional compositions

Nutritional composition of buttermilk

Modern buttermilk has today mostly water, milk sugar lactose, and one of the best proteins you can take: the milk protein casein. Buttermilk is high in calcium, vitamin B12, and riboflavin (source), but tends to have lower fat content than kefir.

Nutritional composition of kefir

Kefirs are highly praised among the other fermented foods. The microorganisms in kefir provide health benefits that are almost one of a kind. During the fermentation of kefir, several organic compounds, beneficial bacteria, and amino acids are produced. Kefir has a quite good amount of proteins (like casein) that are easy to digest. Our bodies are happy with all the vitamins and essential amino acids that help our body to heal and keep functioning. (Source.)

The milk kefir made with kefir grains has more than 50 different yeast and bacterial spices! The most common ones are lactic acid bacteria, and acetic acid bacteria, like Lactobacillus. (Source.) No wonder why kefir has the status of the gut healing food!

The fermented beverage kefir is made usually with skimmed milk or semi-skimmed. It contains less than 10% fat, about 2,7% protein, and 0,6% lactic acid. Milk kefir is high in vitamins (especially B1, B5, and C) and is a great source of amino acids. One interesting thing I found is that kefir contains an amino acid called lysine, which is important in running our central nervous system. (Source.)

Differences in nutritional composition of buttermilk and kefir

Buttermilk is a good source of nutrients like protein, riboflavin, and calcium. On the other hand milk kefir takes it one step further with plenty of beneficial bacteria and being a good source of amino acids. Neither of them contains much fat, but buttermilk tends to have a lower fat content. In nutrition, kefir tends to have more beneficial probiotics, calcium, and protein than buttermilk.

Health benefits of buttermilk and kefir

«For a summer beverage there can be nothing more healthy and strengthening than buttermilk… »

(Halls Journal of Health, 1881)

Health benefits of buttermilk

Buttermilk is low in fat and calories, which is a good option for those who need to watch their calorie intake. The probiotics in buttermilk heal and help your gut microbiota and it is a good source of calcium too. Because of the lactic acid, the lactose in buttermilk is easier to digest. The lactic acid breaks down the lactose which is a relief for those who have lactose intolerance.

Other advantages of buttermilk according to science may be:

Health benefits of kefir

Several studies show that regularly consumed kefir has many health benefits and boosts gut health. It is an amazing historical probiotic drink with unbelievable potential to promote one’s health. Well-researched kefir contains plenty of vitamins, probiotics, protein, and calcium and may have several health benefits when regularly consumed according to several studies:

Two glasses full with buttermilk and kefir on a wooden surface.

Buttermilk vs kefir: Key points of their health benefits

There is more data and research on kefir than buttermilk. Both have amazing effects on our health, especially gut health. Both are easier options for lactose intolerants because they have lower levels of lactose due to the fermentation process. Buttermilk seems to be a better option for those with high cholesterol because of the low-fat content.

How much is safe to use buttermilk and kefir daily?

How much is ok to drink buttermilk

Though buttermilk is low in calories because of the skimmed milk used in making it, you will not want to go overboard with this fermented drink. Sodium levels might be quite high in shop-bought buttermilk and it can cause problems with high blood pressure, heart, and kidneys (source). 

If you tolerate dairy and you do not have high blood pressure or you make the buttermilk yourself, it is a good addition to your healthy daily diet. Around 250ml (about one cup) tends to be good for daily consumption.

A hand pours milk kefir from a glass jar to a glass that is almost full already.

What is the limit in consuming kefir?

Generally, milk kefir is safe to use daily but for a healthier and balanced diet, you should keep the amount in about 240ml-700ml (1-3 cups) a day. If you drink too much it might cause side effects like digestive issues and it might not be for everyone. (Source.) The rule of thumb is everything in moderation with the kefir too. If you have not consumed milk kefir before, start slowly and increase gradually the intake. Same way when starting to consume any other new fermented milk product. Small portions daily are more beneficial for a healthier gut microbiome than huge buckets now and then (source).

But when you should not consume kefir? If you have a high cholesterol level or you might have allergic reactions. If the milk protein is not favorable for you, try water kefir instead to achieve similar benefits to your gut health. (Source.) 

The key points in safe use of buttermilk and kefir

Always in moderation. Everything will be bad for your health if you exaggerate. Regular use is beneficial to you, but keep the buttermilk in about 250ml and kefir up to 700ml a day. Better seems to be to use consistently than drink huge amounts.

How do Nordics use buttermilk?

Nordics tend to use lots of buttermilk and nowadays some fluently swap it for kefir instead in the traditional recipes. Here are some conventional Finnish dishes with buttermilk.

Buttermilk loaf bread

Buttermilk loaf bread, piimälimppu, has buttermilk to make it fluffier and increase its shelf life. Traditionally it is made with rye, wheat, and some syrup

Buttermilk flatbread

Buttermilk flatbread, piimärieska, can be made with barley, buckwheat, or oats – almost with any flour in hand. The breads are flattened very thin and have a round shape. Usually served straight from the oven with some butter.

Sweet rye bread

Sweet rye bread, saaristolaisleipä, the name means “archipelago bread”, for it is traditionally baked on the archipelago side of Finland on the southwestern coast. Bread is black colored, dense bread loaf, that is made with buttermilk, rye, malted barley and glazed with syrup – it is so yummy. It goes perfectly with the soft kefir cheese spread and a bit of chives sprinkled on the top.

On the wooden board, some Finnish sweet rye bread spread with soft kefir cheese.

Bread rolls with buttermilk

Bread rolls, sämpylät, the buttermilk gives nice fluffiness to the bread rolls. The breakfast bread rolls were our must-have for our childhood on weekend mornings.

Buttermilk cake

Buttermilk cake, piimäkakku, is a bundt cake with buttermilk used to moist the cake. It has several Christmassy spices like cinnamon, cardamom, and cloves. The cake becomes better in time and can be stored in the fridge for up to two weeks, thanks to our friend buttermilk.

Buttermilk cheese

Buttermilk cheese, piimäjuusto, is made with buttermilk and eggs that are cooked together and strained. The buttermilk cheese is pressed to the mold and stored in the fridge. It resembles quite much the hard kefir cheese.

How to use buttermilk and kefir in baking

How to use buttermilk in baking

Buttermilk has stabilized its place in baking. It is amazing for biscuits, scones, muffins, pancakes, and bread doughs. Fresh buttermilk is good for dressings or potato salad and canna cotta for example.

The buttermilk curdles easily because of heat, salt, acid, or mixing hard. The acidity is the thing why the buttermilk is used in a recipe. It gives flavor and thickness to the dough too. The acidity comes as a byproduct of fermentation and that acidity makes your bread rise with the help of baking soda. Buttermilk acidity will activate the leavening agent and cause the tiny bubbles that finally make your bread rise.

Try using buttermilk when baking semolina flatbread harcha instead of milk, to enhance the flavour.

How to use kefir in baking

You can substitute quite freely the buttermilk in any conventional baking recipe. It has similar lifting properties due to the similar acidity to buttermilk. Try using kefir in pancakes, crêpes or bundt cakes!

Key points in the use of buttermilk and kefir in baking

The acidity of buttermilk and kefir is unique in baking and they both give a nice lift to the baking goods. Try to swap milk or yogurt for the buttermilk or kefir in the recipes you already love. Use the kefir in your morning pancake or waffle batter when you make them next time.

I RELATED: Crispy and soft waffles without milk | Easy recipe

How to use buttermilk and kefir in cooking

How to use buttermilk in cooking 

The flavors of buttermilk are amazing in cooking. Use the buttermilk to soak the fried chicken before frying to give an extra oomph or use it to the chicken before breading it. Try to add it to soups or salad dressings to get that lovely tangy flavor.

How to use kefir in cooking

Try kefir mixed in yogurt or a smoothie. Make overnight oats with kefir or use it in salad dressings to get a nice tangy twist. Cook from scratch and make your homemade kefir cheese and top your salads or sandwiches with it.

| RELATED: How to make Soft Kefir Cheese and Whey from Milk Kefir

A half of a glass jar filled with soft kefir cheese. Behind on a wooden plank two sweet rye breads spread with the soft kefir cheese.

Key points on how to use buttermilk and kefir in cooking

Both buttermilk and kefir can be used in similar ways to add oomph and tangy flavor to the portion. If you are easing into the tangy flavors, try to mix a bit of kefir into your morning yogurt the start to know the taste of it.

How to substitute buttermilk and kefir

The best buttermilk substitute is actually milk kefir. Buttermilk can be substituted with kefir in a 1:1 ratio and vice versa. There are many options for a quick buttermilk substitute starting from lemon acid and milk, but they do not deliver their job in baking that well. On the other hand, yogurt goes nicely in many recipes especially when you replace buttermilk or kefir milk in the smoothies and such where the thickness and consistency don’t need to be that accurate.

Where to find buttermilk and kefir in Finland and how much it costs

Buttermilk is common in Finland

The price of buttermilk in Finland is fairly affordable with the lowest price (2024) of about 1,45€ per liter (1.57 USD). Buttermilk can be found generally in all grocery stores, for it is quite a common drink here. 

Kefir the semi weird newbie

Kefir is more rare in shops in Finland and the smallest stores do not always have plain natural milk kefir in their selection. Plenty of flavored kefir drinks for snacks you can find several though! The lowest price (2024) for plain kefir is shy under 3 € per liter (3.25 USD).

The differences in price and where to find buttermilk and kefir in Finland

In Finland, the price of buttermilk (2024) is about half of the price of plain milk kefir. As well the buttermilk is more commonly used here in Finland and regarded as a traditional drink, so you most likely find it in the stores. Unlike more unusual kefir milk, which is still regarded as a bit odd drink.

Short on time?

Pin it for later!

Two glasses side by side filled with buttermilk and kefir.


In the comparison of buttermilk vs kefir, kefir seems to have the upper hand. Kefir is the one that has more gut healing properties like probiotics and protein and it is also thoroughly researched. Kefir is also stronger in flavor and has more sour and tangy taste than the milder buttermilk. On the other hand, buttermilk has stabilized its position in cooking and baking and it is the best friend of many homemakers when comes to baking cakes and pancakes. Buttermilk has also generally lower fat content which definitely has its advantages. Both are affordable to make at home. Homemade buttermilk has a lower starting cost than kefir, but the everlasting kefir grains make milk kefir easier and cheaper to produce at home in the long run. Both have their place and advantages and they are both an excellent addition to a healthy and well-balanced diet that cherishes your gut health.

Which one do you prefer? Buttermilk or kefir?

Let me know in the comments which one is your favorite and why. Do you use them daily? Do you use them in cooking and how? Tell me more about how you use these amazing probiotic drinks to heal your gut microbiota!

Read other Know & Learn posts

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *