Producing your own milk kefir

We read a lot about probiotics and how good they are for us. They would boost our immune system and are related to the happiness hormone Serotine as well. That’s for me a good reason to include a glas of kefir each 2 or 3 days as good habit.

Kefir? What are you talking about?

Kefir is a fermented milk beverage produced by the action of bacteria and yeasts that exist in symbiotic association in kefir grains. The artisanal production of the kefir is based on the tradition of the peoples of Caucasus, which has spread to other parts of the world, from the late 19th century, and nowadays integrates its nutritional and therapeutic indications to the everyday food choices of several populations. The large number of microorganisms present in kefir and their microbial interactions, the possible bioactive compounds resulting of microbial metabolism, and the benefits associated with the use this beverage confers kefir the status of a natural probiotic, designated as the 21th century yoghurt. Several studies have shown that kefir and its constituents have antimicrobial, antitumor, anticarcinogenic and immunomodulatory activity and also improve lactose digestion, among others.

Source: US National Library of Medicine

You could buy milk kefir products in your super market. But they would only contain a small subset of all the good probiotics that are available in your own produced milk kefir. The process itself isn’t that hard. The most difficult part is to fetch some kefir grains to start your first brewing. Once you have these, you can keep them forever and pass to the next generation. Notice that it is impossible to start brewing with the kefir you buy from the supermarket!


  • a plastic sieve
  • one glass jar
  • small rag to seal the glass jar
  • elastic to keep rag on the jar
  • full milk
  • the kefir grains

Notice the use of a plastic sieve. Apparently, the kefir grains do not like iron and would die from it. So don’t use it and buy a plastic one for this process only!

Start brewing

I will describe the way I produce my milk kefir in a nutshell.

1. Put the kefir grains in the jar

Make sure the glass jar is cleaned out. After each brew, I clean the jar with only some hot water and dry it out.

2. Add milk to the jar

I always use full milk. And to calculate the amount of milk you need. Just use a factor of 10. So if you have 40 gram of kefir grains, just add around 400 ml full milk to the jar.

3. Seal the jar with a rag and an elastic

Because of the fermenting process that is going on, you should never close the jar completely.

4. Put the jar in a dark spot with constant temperature

I put mine in a kitchen closet. After one day, the milk kefir is typically ready. Sometimes it takes some more time. It depends on the temperature, so in winter it could take some extra time. But after a while you will notice when it is perfect for you. You will notice the watery substance at the bottom and side of the jar. Than it’s ok.

5. Take a glass or other jar and use the sieve to filter the kefir grains

The same process can be followed batch after batch. The amount of kefir grains will even grow. So at certain times, you can please friends with it.

Sometimes the process goes too fast. You can slow down the process one or two days by putting the jar in the fridge. It will slow down fermenting process. You could even stop brewing for some months when you don’t want to. You just need to make sure the kefir grains are cleaned with water and put in the freezer. They are just deactivated that way and could survive for months.

The process illustrated



  • Even people that are lactose intolerant1 could drink milk kefir since the sugar will be completely gone after the fermentation process.

  • Your milk kefir contains alcohol. A small amount of naturally occurring alcohol is typically present as by-product from the fermentation process.

  1. is when your body is not able to process the sugar of the milk