Is Kefir Supposed To Be Thick?
If so, why is my milk kefir quite thin and curdy?
The question of thicker kefir came from a customer who purchased milk kefir grains and was surprised at the thin texture.
If you have bought kefir in a plastic jug from the supermarket, you may be expecting a thick, somewhat viscous liquid… something like a runny commercial yogurt. The truth is, most companies use gelling or thickening agents to make their kefir look and feel like that.
If you look at the pictures below you will get an idea of what thickness you can expect from your kefir. Both are perfectly normal.
These pictures are from Tammy over at TammysRecipes.com
In the first picture the kefir is made with skim milk (fat free milk) and in the second picture the kefir is made with whole milk (full fat milk). You can see that just by varying the amount of fat in your milk you can affect the thickness.
The viscosity (full smooth feel) that is found in the second picture is not simply a result of fat content. This texture is attained through healthy reproduction of the kefir grains and the production of kefiran. Kefiran is the slimy stuff you see sometimes on the outside of the kefir grain. When you pull apart a healthy kefir grain you should see stringy stuff as you break it apart… kind of the way hot mozzarella cheese looks when you take a steaming slice of pizza. So it is the kefiran that gives home made kefir a lot of the viscosity.
There are a couple of things you can do to increase the growth of your grains, and the kefiran (and thus increase the viscosity and thickness of your kefir.
In fact there was a scientific study undertaken to discover just that. The conclusion of this study was that room temperature and "agitation rate" or how often you stir it, were the 2 largest factors. The best temperature to encourage kefiran and kefir grain growth is between 25 and 30 degrees celcius, with 25 being the optimum temperature. It was also discovered that an agitation rate of 80 RPM was best. In the kitchen setting, the first one is hard to achieve in a Canadian kitchen in the winter, and the second one virtually impossible in any kitchen. This certainly explains why my kefir is thicker and has a more pleasant mouth feel in the summer months.
My goal when making kefir is simply to keep my (unheated) incubating cupboard as warm as possible and stir (or gently shake) as often as possible. Whenever I have the oven or stove top on I move my kefir closer to the stove to take advantage of the heat. Otherwise, I keep it in a cupboard over the stove, on an interior wall.
More milk is better than less milk, and a higher volume of milk encourages the production of kefiran. NOTE: I used to recommend 1 tablespoon per 1-2 cups like everyone else on the internet, but after reviewing the scientific data, it appears that the grains grow faster and stay healthier in MORE milk! So I now put my grains in more milk. 1:50 kefir grains:milk – 1 tablespoon of kefir grains in 3 1/4 cups of milk!
I remember reading a story about how kefir would hang in the doorway of a Caucasus mountain home, and everyone who came through the door gave the sac a poke on the way by, thereby stirring the contents.
There are other things that encourage the growth of the grains and kefiran. The type of sugar lactose, not surprisingly, which explains why the grains will shrink and eventually die if they are used to culture non-dairy milks and other liquids. Added vitamins did not increase the thickness nor other additives. It has been observed that lower fat milks do produce a thinner result.
The final trick to thickening your kefir is refrigeration AFTER you strain the grains. Some people call this the "second ferment". After straining the grains you can always drink your kefir immediately, but I really love it after it sits for a bit in the fridge. The procedure that gives me the thickest tastiest kefir is to put the strained and grainless into a mason jar, screw on cover and put it in the refrigerator for a couple of days (24-48 hours or more). The kefir will not only get thicker, but will get quite fizzy. You might think this would also cause it to get more sour, but I find the opposite to be true. To my taste, this refigerated milk kefir gets more tangy (as opposed to sour) and has a fuller flavor.
So the trick to thick kefir, and growing kefir grains is higher fat content, a warm kitchen, and frequent stirring, and finally to refrigerate after straining the grains, for a second ferment.
Even after all is said and done, I do not get thick kefir like Tammy's in the winter. It is just to cool in the house. Here is what my kefir looks like in the winter. As you can see, it is somewhere between the two examples above.