Straining Milk Kefir Grains
Milk kefir is extremely simple to make on a regular basis. Put grains in milk, let it culture, take the grains out and transfer them to new milk. But getting the grains out of the cultured kefir can be the part that has the steepest learning curve. If you are not experienced with making milk kefir, it can take some time to work out the best method for separating those little clumps of culture from the surrounding kefir, especially if the kefir is very thick.
However, once you get the hang of it, it's pretty easy, and takes only a few minutes each day.
In the pictures below, the cultured kefir has begun to separate, indicating that it might have cultured a bit too long, or at too warm a temperature. Note the semi-clear liquid at the bottom of the jar, and around the edges of the kefir at the top of the jar. To incorporate the liquid (whey) back into the kefir and thus make the kefir a little easier to strain, put a lid on the jar and shake it briefly.
Set up a strainer over a bowl. You can use a small strainer or a large one. A large one will let you strain more kefir at once. You can also strain directly into the jar you'll be storing your kefir in, but the bowl gives you more room to work and lets you use a larger strainer.
As you pour the kefir into the strainer, some will just pass right through into the bowl. You might need to encourage the kefir to continue straining. You can do this by stirring it, or gently scraping the bottom of the strainer with a plastic spoon, a wooden spoon, a silicon or plastic spatula, or even your very clean fingers.
If the kefir is very thick, you can give the straining a little boost by tapping the strainer against the edge of the bowl, or shaking it from side to side. You can even pour the kefir out onto a plate, where the grains will stand out and become more visible. (Milk curds will "squish" if you press them gently with a finger or spoon. The grains are firmer and more resilient.)
Eventually you will be left with nothing in the strainer but the kefir grains. It is okay if there is some kefir still surrounding them. Collect them up with a plastic or wooden spoon. Fill your new container with fresh milk, and add the kefir grains. All you need is about a teaspoonful of grains for a quart of milk. Now cover the jar with a filter and set it out to culture.
You can pour the finished kefir into jars for storage, or drink it right away!