Milk Kefir FAQ: Adjusting Quantity & Timing

Questions in this Section:

How much or how little milk (and grains) can be used?
Do kefir grains need to be fed every day?
How much or how little kefir can I make?
How short or long can you ferment kefir?
Can kefir grains adjust to ferment more milk?
What are the seasonal differences in kefir (summer vs winter, etc)?
How do you encourage sluggish kefir grains or relax over-active kefir grains?
How fast do kefir grains grow?
What temperature does milk kefir prefer?
Can you use kefir liquid as a starter (instead of the grains)?

How much or how little milk (and grains) can be used?

Kefir starting out (after being stressed during mailing or from being dried) will usually ferment between a 1:6 - 1:8 ratio. This means 1 tablespoon grains will ferment about 1/2 cup milk, and in time it will increase to about 1:12 (1 tablespoon grains in 3/4 cup milk) to even 1:32 or more (1 tablespoon grains in 2 cups milk). Try using a ratio of grains to milk of about 1:7 - 1:15 for colder climates and 1:20 to 1:60 for warmer climates once they are strong and balanced. Not all kefir is the same; some kefir grains will ferment a glass of milk much quicker than others. We have seen some grains so sluggish it took a cup of grains to ferment 2 cups of milk in 24 hours. Both have benefits - if you have fast grains, you will need less and it could possibly ferment in about 12 hours (especially in the summer). On the other hand, if you have slow grains, you can use more, and have kefir every 24 hours (easier to keep up with). As long as they are growing and producing kefir out of milk, the speed and strength is more of just the character of the particular grain you have, and not something to worry about either way. If your kefir is too sour or separating far before your usual straining time, simply adjust to less grains, or more milk. If you use too much milk, the milk can go off before the kefir grains have a chance to ferment it though, so be sure to understand how much it can do, and gradually increase from there. To get lots of kefir quickly with just a few grains simply keep adding milk without straining. The finished kefir will act as somewhat of a starter along with the grains, quickly turning each addition of milk to kefir. For example, with 1 tablespoon of kefir, you may pour in 2 cups of milk, wait 24 hours, add in another 4-5 cups milk, then in about 12 hours you can top it off with another 9 cups of milk and you will have a gallon of kefir in just about 2-3 days. When kefir is fermented with a higher grain to milk ratio, it will have more acetic acid, less lactose sugar and it will be more sour. Kefir fermented with less grains will be more mild, have more lactose sugar, and more lactic acid (vs the acetic acid).

Do kefir grains need to be fed every day?

The short answer is yes. Kefir grains need to be strained every 24 hours (or 48 at the max) and given fresh milk. The exception to this is if you ferment directly out of the fridge which takes about a week. It's not that common to ferment directly out of the fridge, but it can make a more bacteria rich kefir (more sour and less fizzy). If you or your grains would like to take a break, stick them in the fridge, refreshing them weekly with new milk. This can be done for a couple weeks, then they should be brought back out to room temperature. If you need a longer break, view our section on storage. Some people ferment directly out of the fridge

How much or how little kefir can I make?

This is entirely dependant on the amount of grains to milk that you are using. There is no specific amount, nor any kind of limit. If you would like only a cup of kefir a day, simply use just a few tiny grains. If you want a gallon a day, you will need to use around 16 tablespoons (or 1 cup) grains.

How short or long can you ferment Kefir?

This is completely dependant on the temperature as well as the volume of grains per milk that you are using. For example, if you have a cup of grains in a cup of milk (not recommended), it will ferment very quickly. If you have a teaspoon of grains in 4 cups of milk (not recommended either), it will ferment very slowly. If you place the kefir and grains in the fridge, the same ferment that will usually take 24 hours may take 3-5 days. Likewise, this same scenario in a hot room may take a half day (12 hours). The traditional way to make kefir is to find the balanced ratio of grains to milk (+ temperature of the room) that will create a ferment that is just ready at 24 hours. This produces the optimal flavor and consistency, and the grains seem to thrive off this schedule. You can also do a secondary ferment-hybrid by straining your kefir at 12 hours, and then letting it ripen for another 12-48 hours (without the grains) before drinking. It produces a mild full flavor and is especially good when done in a bottle with an airlock lid.

Can kefir grains adjust to ferment more milk?

Yes, kefir grains will naturally try to adjust their metabolism to match the amount of milk supplied within a given feeding. If you want to try to increase your grains metabolism, simply increase the milk in increments each time you strain and put your grains in fresh milk. You can try starting at about a 5%-10% increase each time and see how they adapt. You can try as much as 100%, leaving it to kefir until its done (may take longer than the usual 24 hours), but this sometimes proves to be a bit too much in one go. Decrease if they seem too sluggish for that much milk and increase gradually, letting them adjust and come up to speed.

What are the seasonal differences in Kefir (summer vs winter, etc)?

Kefir, like all living organisms, goes through intricate and subtle changes with the seasons, climate, temperatures and environment it is in. Just like you can mark the seasons with a tree budding, growing, turning colors and discarding its leaves, kefir also will constantly be in flux and going through seasonal patterns. Kefir will ferment much more quickly in the summer and warmer temperatures. It will be thinner and may be more lumpy or inconsistent as well. It may especially be inconsistent during spring and fall, or whenever there is a large disparity of temperatures (such as a cold night and hot day). Kefir will tend to be more creamy and mild in the winter and cooler temperatures (and more zesty and sour in the summer). Part of the beauty of the symbiotic nature of kefir is that each strain has a certain strength and weakness. Together, they are able to ferment at a wide range of temperatures. Keeping this in miind, you will realize that because of this, a certain temperature will allow some strains to perform much better, while others may be temporarily suppressed. This contributes to the differing tastes and textures of kefir throughout the year. Some people notice it is more cheesy in the winter (possibly due to the certain yeast and other strains being stronger), while in the summer it may be more bread-ish and light in flavor.

How do you encourage sluggish kefir grains or relax over-active kefir grains?

Kefir grains can sometimes get a bit yeasty and zealous (usually due to higher temperatures), or a bit sluggish (stressed or cold). To correct this situation, its best to take them out of their milk and rest them in some clean water in the fridge for about 3 days. You may also help balance them by resting them buried in a small cup of plain yogurt with live cultures for 2-3 days (such as Dannon plain or Stonyfield plain). You can even do this for up to a week if desired. Then simply take them back out and resume fermenting. The first batch may be off-balance, we recommend to wait until it smells 'normal' in a day or a few to consume. We found one bottle in our fridge we had forgotten for about a month, and when we restored the grains they produced the creamiest smoothest kefir we had gotten yet!

How fast do kefir grains grow?

Although not nearly as fast as water kefir grains, milk kefir grains do grow and you will soon have much more than you started with. They typically grow about 5% during the winter or under cooler conditions and 10% to 25% during summer or under optimal warm conditions. It is also interesting that smaller grains will reproduce much more rapidly than larger grains (this is because there is a greater surface area that can grab nutrients from the milk).

What temperature does milk kefir prefer?

Between 65º - 82ºF (18º - 28ºC) is its best functioning range. 71º F (22ºC) is the most ideal. Anything above 86°F (30°C) can be damaging. Kefir can actually still ferment anywhere from 39°F to 86°F (4C°-30°C). This is why it will continue to ferment in your fridge, just at a much slower pace. If you live in a tropical or very hot climate, you may need to make some adjustments so that your kefir isn't contstanly exposed to excessive heat (82°F/28°C or more). You can try fermenting in the fridge during the day, and letting it sit out on the counter during the night. Or you can immediately place the kefir in a thick cooler after pouring cold milk into it (or add cool water or a little ice pack in the cooler to help keep it cool). Try using a ratio of grains to milk of about 1:7 - 1:15 for colder climates and 1:20 to 1:60 for warmer climates.

Can you use kefir liquid as a starter (instead of the grains)?

Yes, kefir liquid contains billions of microscopic organisms that are effective at making a yogurt-like consistency out of milk when you stir in a tablespoon or two in a cup or two of milk and let sit out or in the fridge for 24 hours. It will dilute and get weaker each time, so its best to start with freshly made kefir (from kefir grains) each time for the freshest and safest ferment. But this is a great option for fermenting other liquids or making a quick batch in a pinch.