Milk Kefir Second Fermentation

What is a second fermentation??

To put it simply, the first fermentation is done when your milk kefir grains are added to milk and cultured for approx 24 hours. Now, once you strain out your kefir grains with a plastic strainer and pour the strained kefir into a jar the milk kefir is then ready to consume OR…

You can store the milk kefir (with the grains removed) in your fridge in a sealed jar, and it will continue to ferment. This is what is known as the second fermentation. This second fermentation will mellow out the flavor and produce a much thicker kefir, it also increases the bacterial content, and will make your kefir fizzier. You can also do a second fermentation on your counter top (again with the grains removed) .. either way will work and it’s usually a good idea to add your flavouring during this second fermentation.

One of the most important things you need to know is that, after your first fermentation (when you have milk kefir ready to consume), you have two options:

  1. Add flavour and drink it right away by blending in fruit or vegetables or other ingredients to make your favourite smoothy.
  2. Add flavour and wait, this is called a second fermentation (and usually produces more carbonation and more flavour). Remember, kefir will continue to ferment until consumed, so the flavor will continue to develop over time.

What flavours can I add during this second fermentation??

The flavour possibilities of the second fermentation stage are endless. You are only limited by your imagination. You could for example add: chopped fruit, sweeteners, spices, veg & herbs etc.. or you even drink the kefir plain as some people tend to like the plain kefir but we much prefer the flavoured kefir.

Here are just some of our favourite flavourings:

Fruits: Apple, Mango, Strawberries, Banana, Blueberries, Blackberries and Peaches all taste sweet and fresh.

Spices: Nutmeg, Cinnamon or Cocoa Powder for sprinkling on top or whisking into your kefir.

Sweeteners: We also enjoy our milk kefir recipe with a little honey or other sweetener such as Maple syrup..

Veg & Herbs: Onion, Basil, Thyme all work well..

…the list just goes on and on and really comes down to personal preference.

Just remember by doing the second fermentation of your milk kefir, you will get a creamier, less sour tasting kefir. So even if you don’t add in any fruits etc.. we always recommend a second fermentation.

How long does a second fermentation take?

A second fermentation can take anywhere from 8 to 48 hours and really depends on the culturing conditions (what the temperature is in your home) and also of course, your choice of taste. In general the colder it is, the longer the second fermentation will take and vice versa the warmer it is the quicker the fermentation will be. You can stop the second fermentation at any point if you want to and it’s always a good idea to taste the kefir every few hours until you are fully satisfied with how it tastes.

What next??

Ok, so let’s not complicate this any more than we need to, once you stop the second fermentation you can either remove the flavourings BEFORE bottling your kefir OR you can leave them in if you think the kefir will be consumed within the next day or so but we usually remove them once we are happy with the flavour as leaving them in will change the flavour again.. (remember kefir will continue to ferment until consumed, so the flavor will continue to develop over time). Now go ahead and bottle up the kefir and place in the refrigerator until you are ready to consume it.


When fermenting more than one live culture at home, we suggest a distance of at least 4 feet between the cultures at all times. This is to help stop cross contamination of the different cultures and is of particular importance when culturing dairy products. The only exception to this is when cultures are being stored in the refrigerator with tight-fitting lids.