Kefir Culturing
If you happen to be unfamiliar with it, Kefir is a “probiotic” culture of sorts very similar in many ways to Yogurt. Kefir, however, has a bit more of a diversity of microbiota involved including various strains of Lactobacillus, Bifidobacterium, Yeast, Acetobacter, and other beneficial microbes. Yogurt is generally limited to a fairly small spectrum of only a couple of strains of Lactobacillus. The main difference, when it comes to making your own, is the temperature range needed to culture properly. Whereas Yogurt is what is considered “thermophilic” requiring a fairly warm environment to breed, the microbes in Kefir are able to culture at room temperature or lower, with less of a necessity for sterilization or pastuerization.
When cultured in milk, the microbial culture in kefir itself actually tend to coalesce together into small clumps which are referred to as “grains”. Batch after batch, the grains will grow larger, at which point you can divide and use for other types of cultures such as water kefir, pickling of various vegetables, and kimchi.
Anyway, I like to do a two stage type thing as there are some parts of the culture which thrive at refrigerator temperatures. Milk starter grains can be purchased online fairly cheaply, which you will need to begin. Try to avoid using commercially produced grocery store grade kefir, though. It lacks some of the elements which allow the culture to bind together, so, no grains will coalesce. The same goes for water kefir, so it is recommended to keep a small milk starter going just for the sake of having grains, even if you are just doing the non-milk versions.
Equipment Needed:
1. Kefir Starter Seed
2. 3 Cups Milk (pick your favorite fat percentage)
3. 1 Quart Ball Canning Jar
4. A Piece of Cheesecloth or Linen (to cover the width of jar lid)
5. Wire Mesh Strainer
6. Large Pot with Lid
7. Wooden Spoon with a Long Handle.
Method:
Pre-Prep:
1. Place the jar and the lid rim on its side in a large pot.
2. Fill about ¼ full with water and bring to a boil, covered
3. Allow to boil for about 5 minutes in order to steam sterilize.
4. Cut of the flame, and using the handle of the spoon to remove the jar/lid.
5. Allow to air dry on paper towels until cooled.
Culturing:
1. Pour cold milk into the jar.
2. Place kefir grains in and stir very well.
3. Put the cloth over the top opening, then screw the lid top on.
4. Place in a dark place at room temp for 1 to 2 days checking daily for consistency.
5. Once thickened, move jar into refrigerator for 2-3 days.
Finishing:
1. Using the mesh strainer, strain cold mixture into a large bowl.
2. Save the remaining grains in the strainer and begin the process over, or reserve for other uses.
Note: As with many other sorts of yeasts or bacteria, the grains can actually be frozen for up to 6 months and still be viable. The kefir itself should be consumed within a week or two.
If you’re just interested in Kefir in general, and would like more information and methods, Dom’s Kefir Website is probably the best one that has popped up on the web. Sadly, Dom passed away a few years ago, but his site still exists and is maintained. Also, through the site, there are links to aquiring pure culture keffir grains of various sorts if you are intersted.