Making Yogurt, Kefir & Whey at Home

by Catherine Haug

October 2 Update:  Added section on how to make liquid whey.

This post discusses”

  • Making thermophilic yogurt that cultures above room temperatures, and viili yogurt that cultures at room temperature;
  • Making kefir (from powdered culture and from live kefir grains;
  • Making liquid whey from yogurt or kefir; and
  • A discussion on the difference between kefir and yogurt.

Real Yogurt

Technically, yogurt is a thermophilic culture, meaning the bacteria are most active at temperatures above room temperature (110 – 116 F).  The specific thermophilic bacteria in yogurt is Streptoccus thermophilus.  Don’t be alarmed at the “strep;” only a few strep species cause strep throat.  The word is simply a reference to how the bacterial culture is made onto a slide, and how it appears on the slide, when viewed through a microscope.

Yogurt must also contain Lactobacillus bulgaricus, a bacteria that gives yogurt its familiar tart flavor.

Other bacteria may be added for their probiotic health benefits (such as bifidus and other lactobacillus species); but to be yogurt, the culture must contain S. thermophilus and L. bulgaricus.

It is VERY EASY to make yogurt.  The only hard part is finding the place with just the right temperature, for it to culture.  I have a gas range with a pilot light, so I can use my oven (turned off).  You could use a newer gas or electric oven, with the light turned on, or a cupboard with an incandescent light inside.  Or pour warm water into a well-insulated picnic cooler.

Refer to The EssentiaList: Yogurt & Kefir, from Powdered Culture (132 kb) for instructions on making yogurt.

Alternative “Yogurt”

There are a few other cultures that make a yogurt-like product, and some of them will culture at room temperature. This can be handy if you don’t have that ‘just right’ warm space.

Viili Yogurt

Viili, Piima and Fil Mjolk are mesophilic milk cultures from Finland and Sweden. Early Scandinavian farmers discovered that milk from cows grazing on butterwort pasture clabbered (thickened) better. Such milk is the basis for these cultures.

A yogurt-like treat can be made from these cultures at room temperature! However, the temperature must be maintained fairly constant.  That is, in a steady temperature range of 72 – 75 F for 24 hours, which can be difficult. I’ve not tried this yet, but plan to do so soon.

Another advantage to viili yogurt is that you don’t need to preheat your raw milk to kill competing bacteria.

A disadvantage is that the yogurt may not be as thick as regular yogurt; the richer the milk (with cream), the thicker the yogurt. Another disadvantage is that you must make it frequently, to keep the starter culture viable.

The process in a nutshell:

  • First you make a starter culture (from powder, or from a previous starter batch), preferably using cream, as that makes the hardiest culture.
  • Then add a spoonful of the starter culture to your room temperature milk, cover, and let culture.
  • Remember to save your last spoonful of starter culture to make another batch of starter culture, using cream, or you’ll have to start over with a fresh powder packet.

Refer to:


People think of kefir (pronounced keh-feer’) as a liquidy yogurt.  But really, it is a totally different culture, with different health giving properties.

It is a mesophilic culture, meaning it will culture at room temperature, so you don’t need to preheat your raw milk.

Originally it was made from kefir grains, that resemble coral or cauliflower.  They are not really a grain, but rather a colony of different bacteria and fungi that together make kefir.  You can still make kefir using kefir grains; in fact kefir made from powdered culture does not have all the same species and is thus a slightly different product.

Like viili and piima, kefir made from kefir grains must be made frequently, every 3 days or so, to keep the grains viable.

The main difference between kefir and yogurt is that the lactic acid produced in these cultures are mirror images of each other.  Our bodies respond to these different versions of lactic acid differently, and it’s a good idea to include both in your diet.

  • Yogurt bacteria are transcient in your gut (they will not permanently colonize), and help to keep the gut clean, and to provide food for your native bacteria
  • Kefir microbes may help re-colonize your gut with probiotics, is easier to digest, and helps combat candida overgrowth.

Refer to The EssentiaList: Yogurt & Kefir, from Powdered Culture (132 kb) for instructions on making kefir using powdered culture.

Refer to The EssentiaList: Using Kefir Grains (136 KB) for instructions on making kefir using kefir grains, and more info about kefir grains.

Liquid Whey

Dairy milk contains two protein fractions: casein and whey, that are in solution together in fresh milk. However, upon culturing, the whey will naturally separate from the casein.

Whey is far more digestible than casein, and has the highest biological value (BV) of any known protein. It also contains lactose, vitamins and minerals; and is a very rich source of lacto-bacteria, which makes an excellent inoculant for fermentation projects. It also has healing properties for diabetics: it stimulates the release of insulin, and thus helps minimize blood sugar spikes.

It is very easy to make whey from plain yogurt or kefir (not flavored):

  • Line a strainer with cheesecloth and set over a bowl. Add yogurt or kefir to the strainer and cover with a cotton cloth.
  • If you also want cream cheese, use yogurt rather than kefir, and let this sit at room temperature overnight. The whey will drain into the bowl, and the yogurt will thicken and sweeten into cream cheese. If you use kefir, you will get a sharper, more crumbly cheese that is also delicious.
  • If you are not interested in the cheese, put your straining yogurt or kefir in the refrigerator and let it sit until enough whey has drained off.

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