Milk Kefir FAQ: During the Ferment | Yemoos Nourishing Cultures

Can kefir be in direct sunlight?

This is not recommended, as it can more easily encourage other bacteria to grow if it heats up the jar too much (just like a fish tank in direct sunlight is more difficult to keep clean). For this reason kefir grains prefer indirect light or dim light (such as in a cupboard) or a cool corner of the kitchen counter.

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 add other things in with kefir while its fermenting?

Yes, but experiment carefully as some things may hinder or even harm the grains (some foods contain natural antibacterial properties, such as grapefruit). You can just as easily add the desired ingredients or flavors after you have strained the grains out, and then let the kefir sit for 12-48 hours before consuming. Adding mangos, vanilla beans or raspberries are some of our favorite secondary ferment flavors!

Should Milk Kefir grains float?

Yes, most of the time. Most kefir grains encapsulate some of the carbon dioxide gas that the yeasts give off while fermenting. Also, some grains have less density than the milk, and simply float. Some will be dense enough though (and manage to avoid capturing bubbles) that they sink. Typically if the grains are very bacteria rich or lacking yeast, they may stay at the bottom most or all of the ferment. This can happen after a transit or a rest in the fridge. If you are using dried milk powder, and all the grains are at the top, simply add some more water to increase the density which will allow the grains to relax a bit. Sometimes grains that have been subjected to severe freezer burn, high heat or their outer layer is too encrusted and hard from being dried (or old), also float (and they may not be able to be revived). In this case these grains will usually have a darker color and less soft and sponge-like texture. It is best to see if these are able to propagate new grains (though they themselves may not recover) or toss them if no growth or kefiring is achievable with them. If they reproduce new grains, then you can toss them once you have enough of the new grains (you will be able to still visibly tell which ones are the old, darker ones to be tossed).

Should you stir kefir?

Yes, kefir traditionally is thought to have hung from a bag in a doorway, where it was occasionally knocked around. This helps redistribute fresh milk to the grains (which float near the top). Jostling the jar or stirring the kefir a couple times before its done fermenting is helpful. However, it is not necessary, and there is no need to worry if you cannot get around to it.

Should I put a lid on Kefir?

Putting a lid on kefir while its fermenting will increase the carbonation (fizziness) of the final kefir quite a bit. Kefir grains thrive when exposed to oxygen and seem to do slightly better when the lid is breathable (a cloth, paper towel, etc). Also, it is safer to cover it with a breathable lid because of the risk of built up carbonation exploding the glass. This can and does happen, usually when a bottle is forgotten, or filled too close to the top. Make sure that if you're putting a tight lid on your kefir while its fermenting that you don't fill the jar more than 2/3 full. Just like soda, kefir will expand if enough carbonation has built up and not enough space was left; it will burst and climb right out of the jar when you open the lid. You can also achieve a happy medium by loosely placing the lid on the top to make it a tighter fit than a cloth would be, but still loose enough that air can escape. To avoid fruit flies, be sure that whatever lid or cover your are using, that it is secure and there are no large holes that a small fly (or other floating things like dust or pet hair) could easily get through. Keep in mind that when you bottle and store your strained kefir the carbonation will increase at that point too, so it isn't necessary to try to achieve carbonation during the actual fermentation when the grains are in it. We like to use a cloth and once our kefir is in the fridge for a couple days the carbonation kicks right in!

Does Kefir need a breathable lid?

Kefir functions best when it has oxygen. When you try to go anaerobic (no oxygen), you will be getting basically a carbonated kefir wine. Some people prefer to ferment with a tight lid to increase the carbonation (though this can be done at a later process). It also increases the risk of explosions when the lid is tight. We always ferment ours with a cloth of some kind as the lid.

What type of container can I ferment and store my kefir in?

Glass, ceramic or a food-grade plastic is recommended. Metal can leach when in constant contact with acidic liquids (such as kefir). A thick glass (such as anchor hocking, ball or kerr) with a rubber seal is recommended to lessen the hazard of stored kefir exploding.

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.

How long does it take for dried or live shipped kefir grains to balance?

This can take anywhere from a couple days to a week. Milk differs region to region (and brand to brand), so the grains will also be adjusting to new milk most likely as well. Even large scale suppliers such as Costco and Dannon have regional suppliers, so what's in their gallon in New York is not even from the same farm as the gallon of milk sold in San Diego. Dried grains can take a little longer- a week to 2 at the most. Kefir grains may not start growing right away, but they should be properly kefiring the milk they are in by this time. Growth can start happening right away, or it may take up to 3 weeks before you start noticing growth (usually the case with dried, not live).

How long does it take for stored, frozen or dried kefir grains to reactivate?

Stored grains from the fridge, freezer, or dried in the cupboard are very similar to re-balancing live or dried grains from the mail. It can take anywhere from a couple days to a week. Dried or frozen grains can take a week to 2 at the most. Kefir grains may not start growing right away, but they should be properly kefiring the milk they are in by 5-14 days. Growth can start happening right away, or it may take up to 3 weeks before you start noticing growth (usually the case with dried, not live).

How do you know when the kefir is ready?

When you nudge the jar and the milk is set like a thin gel (vs watery like milk), it is mostly ready. Kefir ferments usually top to bottom, so if it still looks like runny milk at the bottom, leave it for a couple more hours. You will also start to notice pockets (bubbles) trapped within the gel-like milk which will increase until you see just the hint of separation taking place across the entire bottom of the jar (or possibly across the middle if you are stirring occasionally). Once you see this complete separation it is ready. Technically speaking this is at a ph of about 4.5, if you have a ph meter to test. Some people like to drink it once they notice the milk has changed to be more gelatinous and just a few pockets of bubbles forming, while others like a very tart and acidic kefir and will wait until there is quite a bit of separation (up to half the jar being the clear whey and the top half being a thick mass of kefir milk curds). It truly is drinkable at any point so there is nothing to worry about. A mild kefir tends to have a laxative effect and an over-fermented kefir a constipating one, thus most people try to achieve a kefir somewhere in between.

What if I forgot to strain my kefir when it was ready?

Kefir is very forgiving. Strain when you remember, and feed them normally. They may be extra happy and eat through the new milk quickly, so keep an eye on them and strain when it looks ready (whether its before or after the 24 hour mark). If its been more than a week they may need some time to re-balance, and you may want to wait to consume the kefir until after a couple of cycles/batches.