Milk & Culturing Milk (About)

Dairy Cows in the Flathead

Dairy Cows in the Flathead

by Cat, July 2007 (photo, right, by D. Morgan, used with permission)

See also: Butter & ButtermilkCottage Cheese; Creme Fraiche; Ghee; Kefir; Piima, Villi & FilMjolkYogurt; Yogurt Cream Cheese & Liquid Whey (for Lacto-Fermentation); Whipped Cream.

This article discusses: 1. Why culture; 2. Raw vs pasteurized milk; 3. Goat’s vs cow’s milk; 4. Other milks; 5. Equipment for culturing milk.

Culturing of milk is a very ancient process, mentioned in the earliest books of the Bible. There are several reasons for culturing milk:

Why Culture?

  • Perhaps the oldest reason, is to preserve it without refrigeration.
  • To break down the lactose (milk sugar), making milk more digestible for everyone, and especially for those with lactose intolerance.  Many children and adults who cannot tolerate regular milk, find that they have no problems with cultured milk.
  • To break down casein (a milk protein), which is hard to digest, and responsible for many milk allergies.  By breaking it down into smaller peptides and amino acids, cultured products are more digestible than regular milk, and its nutrients are more bio-available.
  • To restore some of the probiotic bacteria lost during pasteurization, in modern times.  [Please refer to my series of articles on Dietary Milk (links to Diet & Health Section of my main website; also my article on Food Safety and Pasteurization on The EssentiaList, for more on this subject.]  Raw milk is very rich in probiotics; culturing cannot restore all of them to pasteurized milk, but it certainly improves the level, making it more health-giving than before culturing. Raw milk is also easier to digest than pasteurization – especially for those who are milk-intolerant due to pasteurization – and culturing partially digests the milk, especially the lactose sugar in the milk, making it more healthful than pasteurized milk.
  • Balances blood cholesterol.
  • Protects against bone loss.
  • Cultured milk has a longer shelf life than fresh milk.
  • Cultured milk is very refreshing.

Raw vs Pasteurized Milk

See also also my article on Food Safety and Pasteurization on The EssentiaList, and Milk:  Why Pasteurize (in the Diet & Health section of my main website).

For these recipes on culturing milk, you can use either raw or pasteurized milk, but the process is slightly different.  No matter which you use, choose milk labeled as “whole,” “low-fat,” or “non-fat” (not 3.8%, 2% , 1%, etc.), as the ‘%’ milks are more highly processed. Note, however, that ultra-pasteurized and UHT milk does not readily culture, and will not form cheese without the addition of calcium chloride.

  • If using raw milk, simply heat the milk to the desired culturing temperature  However, you can also heat to 1800 F to kill all natural bacteria in the milk that would otherwise compete with your specific culture; just remember that 1800 F will also denature all the enzymes in the raw milk.  I have found by experimentation that this is necessary for yogurt, but not for Kefir.
  • If using pasteurized milk, for some cultures such as yogurt,* you must first heat the milk to at least 180°F, to kill any ‘bad’ bacteria that may be lurking in the milk. This may sound counter-intuitive, because pasteurization is supposed to kill the bad bacteria.  However, the truth is that raw milk contains probiotics which naturally keep the bad bacteria in check, but when those probiotics are destroyed in pasteurization, the bad, putrefactive bacteria can proliferate and interfere with the culturing bacteria.

Another reason for heating milk to 180°F for some cultures, is to change the structure of the casein in the milk so that it will culture with that particular strain of culturing bacteria.

After heating to 1800 F, then allow the milk to cool to the desired culturing temperature before proceeding.

* Preheating is not necessary for Piima Cream and Creme Fraiche

I don’t recommend using:

  • Homogenized milk, as the fat globules are changed by homogenization, and may not culture properly. Buy ‘cream at the top’ milk; shake it up or skim off the cream.
  • Ultra-pasteurized milk or cream, as it will not culture properly. However, for cheesemaking, you may have success with ultra-pasteurized milk if you add calcium chloride. Cheese requires available calcium to form the curd; pasteurization, and especially ultra-pasteurization, makes milk’s natural calcium unavailable, requiring more to be added.
  • UHT milk/cream that is shelf-stable and doesn’t require refrigeration. The UHT process destroys most of the nutrient content of milk/cream, and may actually cause harm. For cheesemaking, adding CaCl2 will not make it curd.

Using Pasteurized Milk:

  • Vat pasteurized milk (used by farmers) should make cheese the same as raw milk.
  • HTST pasteurized milk (commercial pasteurized) will likely require the addition of calcium.
  • Ultra-pasteurized (the most common milk in grocers’ refrigerators) is not recommended; it will definitely require the addition of calcium to curd for cheese.
  • UHT pasteurized will not make cheese, even with the addition of calcium.

About calcium chloride:

Unless you are using raw or vat-pasteurized milk, the solution to the curding problem is to add calcium chloride to the milk before adding the rennet. It coms in two crystalline forms: anhydrous or dihydrate. While most sources say to use a 30%solution, they don’t specifying whether this is made from anhydrous CaCl2 or dihaydrate CaCl2-2H2O.

From my research, I find that Dr. Frankhauser’s website suggests about 260 mg calcium per gallon of milk. Both and sell 30% calcium chloride and both recommend using 1/2 tsp per gallon milk. My calculations indicate that 1/2 tsp 30% solution of anhydrous CaCl2 provides 264 mg Ca/gallon milk, but 30% dihydrate CaCl2-2H20 (1/2 tsp provides 200 mg Ca/gallon milk) would also be OK, and is less expensive.

My local compounding pharmacy (Evergreen Pharmacy) made up a solution using the dihydrate, but has the equivalent amount of calcium as a 30% anhydrous CaCl2 solution, so it has slightly more calcium than a 30% solution of dihydrate. It provides ~260 mg per half teaspoon, for treating a gallon of milk.

I base my conclusions  upon the advice of Dr Frankenhauser, from Beginning Cheese Making (2) and email conversation with Dr. F. on  4/5/11:

Molecular weights:  Ca = 40.07 g/mole; anhydrous CaCl2 = 110.98 g/mole; dihydrate CaCl2-2H2O = 147.01 g/mole

30% solutions provide:

  • Anhydrous CaCl2: 108 mg Ca/ml or 529 mg Ca/tsp (264 mg per half tsp) <= best
  • Dihydrate CaCl2-2H2O: 81 mg Ca/ml or 400 mg Ca/tsp solution (200 mg per half-tsp). <= good

You should completely dissolve the CaCl2 in about 1/4 cup water before adding it to the milk. Add it slowly with thorough stirring.” 

On how much/what type to use: Use 1/2 tsp of 30% calcium chloride solution per gallon milk. It doesn’t matter whether it is 30% anhydrous, or 30% di-hydrate.  

  • UHT milk/cream(Ultra Hight Temperature Process): this is a type of pasteurization that destroys most of the nutrient content of milk and cream, and may actually cause harm. For cheesemaking, adding CaCl2 probably will not make it curd.

For more on pasteurization, see The EssentiaList: Food Safety & Pasteurization, or download the pdf file: Food Safety & Pasteurization.

For more on cheesemaking, see The EssentiaList: Homemade Cheese & Tofu

Goat’s vs Cow’s Milk

Many people don’t like the flavor of goat milk, but it is much more easily digested by humans, as goat milk’s composition and structure more resembles that of human milk.  However, goat milk does not thicken as well as cow’s milk during culturing.

Other Milks

Some specialty products are made with mare’s (horse), water buffalo, or sheep’s milk.

You can also culture fresh, raw coconut water instead of or in addition to animal milk for kefir.   Coconut water is the liquid that you can pour out of the coconut, once you’ve opened it.

Coconut milk, is made from pressing the fatty liquid out of the coconut meat, after soaking in water.  It can be used to make yogurt or kefir.  I’ve never tried it for buttermilk or sour cream, but that might work, too. The fats in coconut as similar to those in butterfat (from milk/cream).

Nut milks (such as Almond milk) can be used, but I’ve never tried it.  Nut milks are made the same way as coconut milk, by pressing the fatty liquid from the meat, after soaking in water.

Soy milk can be cultured, but I avoid soy (see my articles on the health dangers of soy).  Soy milk is also made by pressing the liquid from the beans after soaking in water.  However, most commercial soy milk has a lot of other ingredients added, making it a processed food and not a whole food. If you must use soy milk, make your own.

 Equipment for Culturing Milk

  • I use a 2-quart stainless steel pot with a lid to heat and culture the milk for many of the recipes, and a stock pot for those using larger quantities of milk, but you can also use an enameled cast iron pot.
  • You will also need a milk thermometer (reads from 0 to 2200 F).
  • Glass measuring cup
  • Some recipes recommend a blender.  You can use a traditional or a hand-held immersion blender.
  • Some recipes require a glass jar with lid.  I like to use a Mason or Ball canning jar with sealing lid and ring.

Additional equipment for particular cultures:

  • For Yogurt Cream Cheese and Whey Starter:  Same as for yogurt, plus a fine sieve made for this purpose, or a large strainer and a 100% cotton dish towel (the flour-sack variety).  And a bowl over which you can place the sieve or strainer.
  • For Kefir:  vented lid for your stainless steel pot, or a glass jar to be covered with cheesecloth held in place with a rubber band.
  • For Cottage Cheese:  Good quality cheesecloth.  This is not the flimsy variety you can buy at the grocery store.  If you can’t find the real deal, use an old cotton pillowcase, or purchase 100% cotton scrim at the decorator fabric store, and wash several times to soften.

Temperature regulation for yogurt:

I have a vintage gas range with pilot lights.  The broiler is kept warm by the pilot light at just the right temperature for culturing yogurt.  If you aren’t fortunate to have such a range, you can experiment with using your oven with the light bulb left on, or with using a pot of warm water in your warm oven (about 1500 F), as a bath for your glass or stainless steel yogurt container.  You can also try a dehydrator set at 950 F . Or a picnic cooler with a container of hot ware or a light bulb inside.


  1. Nourishing Traditions, by Sally Fallon with Mary G. Enig, PhD
  2. Dr. Frankenhauser:

About Cat

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