Milk Kefir FAQ: Straining & Finishing

Milk Kefir FAQ's 

Part 5 - Straining & FinishingMilk kefir grains

Questions in this Section:

How do you know when the kefir is ready?
How do I remove my kefir grains from the kefir once its ready?
What size strainer is appropriate for straining kefir grains?
Do you have to be gentle with kefir grains?
Do you have to wash or rinse your grains?
How can I reduce the amount of lactose in kefir?
What is 'ripening' kefir and how do you do it?
How do you strain kefir to make it thicker or to separate it from the whey?
How do I get my kefir to be more fizzy and carbonated?
How can I get my kefir to be creamier or thicker?
Do kefir grains need to be fed every day?
How long do active kefir grains last?
How long does it take for dried or live shipped kefir grains to balance?
How long does it take for stored, frozen or dried kefir grains to reactivate?
What if I forgot to strain my kefir when it was ready?
Where can you store kefir?
How long can you store kefir/when should you drink it by?

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.

How do I remove my kefir grains from the kefir once its ready?

You can use a strainer (wood, plastic, nylon, or stainless steel). The kefir will slowly pour through, and if it needs help, shake the strainer or use a spoon to help it strain faster until just the grains are left. Milk kefir grains are not typically fragile, so don't be afraid to push the grains around with some force. You can also keep your grains in a clean, non-bleached muslin bag or unbleached tea bag, and simply pull the bag out when done. This is a nice option to make the process more simple and quick, but the grains sometimes do not ferment as well. You can also use your clean hands, kefir grains don't mind being touched!

What size strainer is appropriate for straining kefir grains?

Kefir grains are pretty fluffy and tangible in size, so you do not need a microscopic, super dense strainer. Any strainer around 1/8" in hole size (or 2mm) is a good starting point. This is basically any strainer that is not a pasta strainer with large or fancy shaped cut-outs for the holes. Most strainers now a days are made from stainless steel or plastic (and its many forms, such as nylon, rubber etc) - both of which are acceptable to use with your grains. We also carry some as well that are kefir-friendly. Bamboo/wood is also a safe material - just make sure to clean it well between strainings. If you prefer to use a finer mesh, it will take longer to strain. Anything bigger, and some tiny curds can slip through and although quite safe to consume, will most likely ferment your bottled kefir too much.

Do you have to be gentle with kefir grains?

Kefir grains are pretty hardy little guys. Just like grass, it can take a good beating but it will wear down over time if exposed to excessive stress. To give you an idea, kefir grains will survive a blender, a hammer, freezing, some heat (but not cooking), and of course, drying. This does not mean they should be handled this way - care for them like you would any pet, and they will be extremely happy and productive for it!

Do you have to wash or rinse your grains?

Some people like to do this, but it was never done traditionally and is not necessary at all. By nature, they are a symbiotic mass of microflora that has self-inoculating properties, protecting itself from foreign bacteria or yeast. The lactic and acetic acids it excretes also protects it from becoming contaminated. Many have observed that when they stopped rinsing their grains, they grew better and produced better kefir. Sometimes they can get fat deposit (crusty, orange colored areas) that may indicate they need a gentle scrub and rinse though. If you wish to rinse them, make sure it is clean, non-chlorinated water. Simply run them under flowing water or swish them around in a bowl of clean water, and pat dry.

How can I reduce the amount of lactose in kefir?

While kefir itself is very low in lactose, you can further reduce it by letting your finished, strained kefir sit in a jar for another day or two before consuming it. This works both out on the counter, or in the fridge (the fridge being more mild). Keep in mind it will contain more acid and alcohol (as these replace the sugars). Because kefir contains mostly converted lactose (to glucose and galactose), as well as lactase enzymes, most people do not require this further ripening, but it is always an option.

What is 'ripening' kefir and how do you do it?

This simply means letting your finished, strained kefir sit out a bit before consuming. This is done to increase the folic acid and B vitamin content (particularly B1, B6 and B9), improve the flavor, decrease the lactose content, and increase the carbonation and alcohol content of your kefir. To ripen your kefir simply strain the grains out, bottle your finished kefir, and then let it sit out on the counter or in the fridge for another day or two. Remember this will make it more acidic by nature of the increasing folic acid. Be careful to store it in a thick safe bottle that won't explode (dangerous and messy!), since the bottle will build up pressure. If in doubt, 'burp' the bottle once or twice a day by opening the lid to let the pressure out and then closing it up again. This won't interfere with the ripening or carbonation process.

How do you strain kefir to make it thicker or to separate it from the whey?

Some people prefer to make their finished kefir thicker by straining out some of the whey that has separated. This is very easy because typically the kefir has already separated while fermenting, and when you go to strain your kefir the whey (clear liquid) will pour quickly through. You can do this over the sink, and then put your bowl or jar underneath to capture the remaining creamy white portion (which goes through the strainer much more slowly). If this does not work, or you want to further reduce the whey, you can line a strainer with paper towel, cheesecloth, muslin, coffee filters or a very thin towel, and place it over a bowl wide enough to capture what drips through. You can store this on the counter or in the fridge, it will work and keep fresh either way. After about 24 hours you will have kefir cream cheese in the strainer, and a bowl below full of whey! This cream cheese is delicious to spread on bread, bagels or to eat with fruit, etc - you can even blend in flavors (ie strawberries or garlic & salt).

How do I get my kefir to be more fizzy and carbonated?

Kefir is only slightly effervescent straight from its ferment - to add more fizz, try bottling it for a few days.Seal your freshly strained kefir in an airtight bottle in the fridge or on the counter for a few days. Leave about an inch between the liquid and the cap (this is how champagne is made, too). To avoid bursting bottles (dangerous and messy!), 'burp' your kefir bottle once a day. Just un-screw the lid, let the pressured air escape, and re-seal it. This will not diminish the amount of fizz, and is actually quite helpful in building up more carbonation without having your bottle explode in the process. It's best to use thick jars with rubber seals to avoid bursting. Sluggish kefir and winter kefir tend to be more mild and yogurt-like, whereas summer kefir can be more fizzy and yeasty. If you think your kefir is sluggish, try giving it a rest (explained below) and then fermenting it in a warmer spot in your home.

How can I get my kefir to be creamier or thicker?

Kefir tends to get thicker and smoother the more productive the grains are. Grains tend to be their most productive when they are on the smaller side, thus having a larger amount of surface area exposed to the milk. The thickest kefir we've gotten is when we threw some grains in the blender to make them as exposed as possible. They fermented the milk quickly and uniformly, grew rapidly, and the kefir's texture was nice and creamy. Other ways to reduce grainy, gritty, lumpy, thin kefir is to switch to creamier milk (more fat), keeping temps steady day and night within 70°F/21°C and 76°F/24°C, not switching milk brands or %'s frequently, and being patient in seasonal switches (such as spring and fall when it can go through a week or two of readjustment). If you are still struggling to get a creamier kefir then the trick may be the timing and the agitation during the ferment. The key with kefir is balance. Kefir can be pushed to ferment VERY quickly if needed, but it doesn't produce desirable results. For example we were able to get ours to separate completely into curds and whey in just 2-3 hours by sitting it on the stove top near hot burners (while we were cooking dinner) and agitating it every 30 minutes. Despite it congealing and completely separating (and looking overly done), when we strained it, it was extremely thin. It still tasted like kefir but its texture was like milk. You can also push kefir to over-ferment, where it becomes a massive separation of very thick curds and tons of clear whey. This is not healthy for the grains to do repetitively, and actually doesn't insure a thick kefir. The grains simply do not need to be in the kefir after a certain point - you can increase creaminess and thickness without the grains. Once you see the first signs of separation (just even a bubble or two of whey at the bottom) then strain your kefir, bottle it, and let it sit out on the counter for 6-24 hours to increase thickness (remember, acidity and alcohol content will also go up). Part of the factor of getting milk kefir thick and creamy is to make sure it has a long and slow ferment so it can develop texture. Agitating it at least once during this process can also help very much to get the milk distributed and fermented more evenly. If your kefir is finishing or separating too much by 24 hours, simply adjust by taking out some grains or adding more milk the next time, until you can get the timing to where your kefir is just barely separating (just the first signs of some clear whey pockets) at the 24 hour mark. Keep in mind that agitating can speed up the process a bit too, so you may need to experiment and add more milk or less grains. Giving it 24 hours to develop taste and texture (and agitating to boost distribution) greatly enhanced your chance for creaminess and you will avoid thin, lumpy, gritty/grainy kefir. Some of the creamiest kefir comes from a 1 week ferment in the fridge (but this is hard on the grains when done repeatedly).

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 long do active Kefir Grains last?

Indefinitely with good care - they are a living, consuming organism that are in a constant state of reproduction. Some may get weaker over time for one reason or another (neglected, frozen, etc), but they will nonetheless do all they can to keep marching on! They have already lived over a thousand years as it is.

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).

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.

Where can you store kefir?

Strained milk kefir can be stored either on the counter or the fridge. It will continue to ferment both ways, the fridge of course being the much slower of the two. If on the counter, it will quickly morph into a rather lathery creamy concoction (with more acid and alcohol) - its best to only do this for 12-24 hours, and then stick in the fridge to slow it down some. You can also store your kefir in the freezer. It will kill off some of the cultures but quite a few will remain viable, and will make excellent healthy and delicious popsicles!

How long can you store kefir/when should you drink it by?

It is best to drink kefir within 2 weeks. Our opinion is that kefir is best about a day or two after you have strained it, and bottled it in the fridge - this allows for more B Vitamins to develop, without risking too much of an increase in acid or alcohol. This gives you time for any secondary flavors to set and meld with the kefir as well. It tends to have a more developed and dimensional flavor and creamier consistency, too. You can continuously add your freshly strained kefir to your existing kefir, giving it a shake to distribute, or you can start fresh each time, dumping what you haven't consumed. Kefir can be stored for quite a long time, since the bacteria and yeast actively and continuously preserve it. However, the alcohol and/or acetic content will increase and it will get increasingly sour and fizzy over time. Bottles left and forgotten in the fridge for a couple months might smell like pickled milk, or creamy wine upon opening them (though not at all rotten!).