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When you first start making kefir you may become concerned with how fast your grains are growing. They may be growing too fast or too slow for what you expect. This is a natural experience which most people have when starting something new. Kefir grains are the physical representation of the size of the culture in your kefir so changes in it can cause some concern.
There are several reasons why milk kefir grains fail to increase in volume as they ferment milk. There may not be enough lactose for the grains to increase much past their present volume, the temperature may not be conducive for growth or the culture is not populated with the needed bacteria.
Kefir grains themselves are not alive but are the structure the symbiotic culture of bacteria, yeasts and fungi create and inhabit. When the grains fail to multiply it is because the culture is either not big enough to maintain more grain structure or the environment where the kefir grains are placed prevents the formation of grains.
Kefir grains are a gelatinous mass of protein, lipids, and polysaccharide which provide an environment for the culture to live in. There is a wide variety of bacteria and yeast strains which make the kefir grains their home. These include bacteria which produce a biofilm which is used to protect the various bacteria in the culture. This biofilm is thought to be the precursor for the kefir grains as it thickens and becomes inhabited with the surrounding bacterial species.
Conditions which affect the growth of kefir grains
Although kefir grains are not living things themselves they are inhabited by a wide variety of bacteria and yeast species. It is these microorganisms which produce the kefir grains. Therefore anything which affects the growth of the culture affects the volume of kefir grains.
Ambient Temperature of the room
Kefir grains are active within the range of 16 to 32℃ (60 to 90℉) but the cultures cannot grow at optimum levels at either end. For your grains to be the healthiest and have the best chance of multiplying maintain a temperature between 24 -28℃ (75 to 82 ℉) in the room which you are fermenting your kefir. This temperature will produce great tasting kefir as well as help the culture to increase their population and produce adequate biofilms which form to make the grains.
How often the grains are fed
The rate the grains are fed has two cases.
Feeding too often
New kefir grains are produced by a symbiotic relationship between the cultures which are present in the original grain. The lactic acid bacteria produce an acidic environment which is better for other cultures production of the biofilms which eventually become parts of the kefir grain.
How the grains are formed is unknown but it appears to be important for the solution to be acidic to some degree so if the milk is changed too often it does not have time to acidify enough for the grains to grow.
Not feeding often enough
To build anything raw materials are needed. Kefir grains are made from the milk which the grains are fed on a regular basis, like anything else in the world they break down and need to be replaced.
This means that if you want your grains to multiply there must be enough raw materials available to maintain the original kefir grain but also enough for new construction. Not feeding your grains enough reduces the amount of raw materials available to make new grains.
What type of food the grains are fed
Milk kefir grains need adequate amounts of protein, lipids and polysaccharides to grow. Lipids are what the structure of most living cells are made from. If the type of milk you feed your grains regularly is highly processed, low fat or lactose free then this may be the problem. Switch to a different type of milk like 2%, homo or try goat’s milk as it is naturally homogenized.
The quality of the milk
To have a healthy culture which is viable and growing it is important to feed it quality ingredients.
Just like you can’t expect to be healthy if all you eat is junk food you can’t expect your grains to be healthy and grow with poor quality food.
For kefir grains that means fresh milk which has not passed its expiry date. Outside of that date the milk may have pathogens in it which cause the milk to go off. Feeding kefir grains milk which is past its expiry date inhibits the growth of the cultures in the milk. They have to change the environment which is currently conducive to the growth of spoilage bacteria to an environment which is good for the growth of kefir grains which slows the rate of growth of the kefir grains.
The current state of the grains
Your kefir grains need to be active and healthy to grow. If you have just rehydrated your grains or have had them hibernating in the fridge for a while it will take a while for them to regain the full strength of all the cultures in the grains.
The type of container the grains are stored in
Why metal containers are should not be used for making kefir
Kefir is an acidic bioactive culture. The grains produce an environment which is slightly acidic which is necessary for the production of biofilms which makeup the grains basic structure.
If you ferment your kefir in a container which has metal in it not only does this add a metallic taste to the kefir it slows the rate of acidification of the kefir as the acid in the kefir will react with the container and cause the solution to remain basic.
Why plastic containers should not be used for making kefir
There are two reasons why you shouldn’t use plastic containers for making kefir:
- Plastic adds unwanted chemicals to the kefir
If you have ever stored water in a plastic container for a camping trip and left it for two or three days you may notice that the taste of the water has a plastic taste to it. This is because some of the chemicals in the container have leached into the water and given it a plastic flavor.
The same thing happens to the milk which you pour into a plastic container. Some plastics are safe for use for food storage but they are not recommended for the production of food. Plastic is made from petro-chemicals which are inherently toxic. Milk stored in plastic containers at room temperature will absorb some of the more volatile chemicals in the container. This affects the growth of the grains.
Even the use of food grade plastic is not recommended as these containers are often used repeatedly and as a result suffer damage. As plastic ages it starts to break up into smaller and smaller pieces. Once the pieces get small enough they can have serious effects on the environment and the health of those organisms living in it.
Whether or not the plastic container is breaking down into microplastics or whether the chemicals themselves are leaching into the milk you can be sure that the addition of petrochemicals into your milk will not help the health of the kefir grains or you.
For the best chance of having healthy grains, store your grains in a non-reactive container, like a glass jar of some type. Another option is ceramic containers but you must be sure it is not cracked and the glaze does not contain any lead or other compounds which are not good for you.
How much oxygen the grains get
The amount of oxygen which the grains get has an effect on the population of the various cultures in the grains. Some of the bacteria can replicate themselves indefinitely without oxygen just as long as they have enough food energy but the known bacterial species which produce the biofilm which is thought to be the precursor of the grains need oxygen to grow.
Reasons you want your kefir grains to grow
There are many reasons why you may want your kefir grains to grow, from ensuring they are healthy to having some for a backup in case you have grain failure.
To have some for a backup
Kefir grains are great because as long as they are treated well they will continue to produce kefir indefinitely, so long as they are getting regular feeding and care they will continue to make milk kefir. They are like any other living thing and so if they are not taken care of properly they can stop growing and die.
Since your grains are dependent on you if something happens to you which interrupts your ability to care for your grains it is nice to know you have some backup grains stored away when you want to start making kefir again. To learn how to store your grains for the short or long term check out this article here.
To give some away to friends
Friends are people who have similar interests and beliefs. If you are socially active and are truly interested in making and consuming your own kefir you will find friends who will also be interested in it. By having grains which multiply you will have extra grains to pass on to others.
To ensure they are healthy grains
Although healthy kefir grains tend to grow, grain growth is not the only indicator of healthy kefir.
Other indicators are smell, flavor, texture and color. If these indicators are pleasing to you then there is nothing to worry about. On the other hand if any of these seem to be wrong then you may need to change something.
For information on how to alter the way you ferment your kefir to better suit your needs read this post.
To increase the production of kefir
The amount of kefir your grains can produce is directly related to the number of grains you have so if you want to make more kefir you will need more grains. You can slowly build up your kefir production simply by gradually feeding more milk to your grains. Ensure that after 24 hours your kefir has thickened and smells nice and fresh. Over time you will be able to increase production to meet your kefir needs.
This is the same method you used to reactivate your grains if you purchased a packet of freeze dried grains. As you add more milk to the grains the population will grow and be able to produce more kefir.
Why kefir grain growth is not the most important consideration
Whether or not your grains are growing is not the issue. The issue is whether they produce enough kefir which is fresh and tastes good for your daily kefir requirements. If you are getting enough kefir which suits your needs then stop worrying about their growth.
If you get enough kefir on a daily basis and your grains grow slowly or not at all then great. You will not have to try and find other uses for your extra kefir grains. Which can be a problem all its own.
If your kefir does not taste the way you like it. It is too yeasty or too acidic then these are indicators that you should adjust the way you make your kefir. You should not adjust your kefir making routine just to produce more kefir grains.
Since kefir grains grow so slowly you may not even notice their growth until one day you sieve out the grains and find you are only getting half the amount of kefir you usually get and the rest of the volume is kefir grains. When this happens you will have to decide what to do with all those extra grains but until then just keep making kefir.