Buttermilk for Baking

Table of Contents

Fluid Milk


Milk, discussed in a reasonably useful Wikipedia entry, is the milk of dairy cows, processed. The fluid milk used in baking, by commercial bakers and home bakers, in Europe and America is mainly cows’ milk. Milk must be taken to a dairy plant to be processed within hours after being harvested in a dairy farm, and only lasts a few days, even with the benefit of refrigeration. Milk sold in retail outlets in North America has been pasteurized – as required by public heath law.

At one point in history, milk was obtained by human by milking cows by hand. Milk is still obtained from cows, but in modern times, the cows are cared for on dairy farms and milked with machines. Milk naturally separate into cream and milk. The high butterfat cream was, historically, churned manually to make butter. The leftover fluid, if the milk had not soured, was sweet traditional buttermilk. If the cream was churned from sour milk, the buttermilk was sour. Milk became sour due to bacteria in the milk, which started fermenting the milk.

A writer for Slate suggested in 2012:

“As long as people have made butter there’s been buttermilk,” says Anne Mendelson, a culinary historian and the author of Milk: The Surprising Story of Milk Through the Ages. Careful: Here, she’s talking about a byproduct of churning whole milk or cream—the thin, white liquid that [Laura Ingals] Wilder wrote about.

So how did that buttermilk, the original buttermilk, turn into the thick, sour, yogurty beverage I sampled … ? The confusion surrounding this drink dates back to the 18th century or before. Until the age of refrigeration, milk soured quickly in the kitchen, and most butter ended up being made from the slightly spoiled stuff. As a result, some historical sources use the word buttermilk … to describe the byproduct of butter-making; others use it to describe butter-making’s standard ingredient at the time—milk that had gone sour from sitting around too long. To make matters more confusing, the butter-byproduct kind of buttermilk could be either “sour,” if you started out with the off milk that was itself sometimes called buttermilk, or “sweet,” if you started out with fresh cream (like Laura’s mom did). So, prior to the 20th century, buttermilk could refer to at least three different categories of beverage: regular old milk that had gone sour; the sour byproduct of churning sour milk or cream into butter; and the “sweet” byproduct of churning fresh milk or cream into butter.

L.V. Anderson, Slate, May 12, 2012, All Churned Around

In industrial dairies, milk is refined by removing butterfat from whole milk with a centrifuge. The process is discussed in web pages other than Wikipedia. Some internet material on industrial dairy methods and science:

Dairies began to manufacture cultured buttermilk:

… the stuff known as cultured buttermilk at your local supermarket—i.e. milk that has been deliberately soured—is a 20th-century invention, and the product of a health-food diet craze dating back to the flapper era.


In Western Europe and America, the only people who bothered to drink buttermilk of any kind were the poor farmers and slaves who needed all the calories and nutrition they could get. Everyone else fed sour milk and butter-byproduct to their farm animals.


While farmers’ wives and other home cooks were using sour milk in their baked goods, America saw an influx of immigrants from parts of the world where sour milk was considered a refreshing everyday beverage. Ashkenazi Jews from Eastern Europe, who have a tendency toward lactose intolerance, may have been especially inclined to drink it, since the bacteria make it more digestible. The nonimmigrant American public was generally mistrustful of sour milk as a beverage until 1907, when [a] Russian biologist … concluded that the relative longevity enjoyed by people living in the Balkans was a direct result of their consumption of sour milk. Health-conscious Americans started going crazy for sour milk, thinking it would prevent aging. At his sanitarium in Battle Creek, Mich., holistic doctor and breakfast-cereal enthusiast John Harvey Kellogg began serving an ultra-tart, deliberately soured version with the catchy name “Bulgarian buttermilk.”

Naturally-occurring sour milk had in the mean time become increasingly rare, thanks to modern refrigeration. So commercial dairies, spotting an unfilled niche, began to culture it themselves, and sold the new product widely as buttermilk starting in the 1920s. This was much like the buttermilk we find in grocery stores today: Made from low-fat milk and lactic acid bacteria that grow best under moderate heat conditions. Dairies used low-fat milk because it was cheaper than whole milk, but still took on a thick, creamy body when cultured.

L.V. Anderson, in Slate, cited above

The milk solids remaining after milk is centrifuged include the cell membranes of the fat cells, casein (a protein) and lactose (a sugar). The casein reacts to acid to curdle milk.

Full butterfat milk – often marketed as Homogenized milk (all milk processed for retail has been homogenized) – is about 3.5 % butterfat. It depends on the cows, the fodder, and the dairy. Fluid milk processed for retail sale is sold as reduced butterfat milk by the percentage of butterfact -ie. 2%, 1%, or as skim milk, which as butterfat content at a fraction over 0%.


Buttermilk, since the industrialization of dairies, has been a dairy product produced by processing fluid milk. Some fluid buttermilk is produced by fermenting partially skimmed milk. Dairies also produce acidified buttermilk – milk treated by mixing milk with an acid. A dairy may use fermentation or acidification or a combination of both. The production methods are not discussed on product labels or in an ordinary dairy’s promotional materials. Nor do bakers say how the buttermilk used to mix dough was made.

The home baker’s hack to make acidified buttermilk, comparable to store-bought dairy buttermilk is to add an acid, in the amounts noted here to one cup of milk:

  • 1 Tablespoon lemon juice;
  • 1 Tablespoon vinegar; or
  • 1 teaspoon cream of tartar.

Available in Victoria BC.

Most retail grocers in Victoria sell pasteurized milk processed by the Island Farms dairy, which distributes a fermented and/or acidified buttermilk said to be about 1.5% butterfat. The weight of a “1 cup (250 ml.)”1A US cup is 236.59 ml. Most cookware manufacturers label 250 ml measuring cups as 1 cup. The people who write recipes mainly say “1 cup or 250 ml.” It usually does not make a difference. serving is not stated. Conventionally, a cup of buttermilk weighs 245 grams (compare a US cup of water at 237 g.).

Dry Milk


Dry milk (aka milk powder) is made by dehydrating milk – removing water. Dry milk can be made with whole milk, or reduced butterfat milk. It is reconstituted by adding water. Dry milk can be added to baking recipe or formula as a dry ingredient. Adding water (or milk) to dry ingredients and mixing the ingredients to make dough is a normal process in baking bread. Manufacturers can dehydrate whole milk, skim milk and buttermilk.

Buttermilk Powder

Buttermilk powder is dehydrated dairy cultured buttermilk, made from reduced butterfat milk. It is possible to substitute buttermilk powder and water or plain milk in a recipe (e.g. for pancakes, cakes or bread) for fluid buttermilk. One way is to mix the powder with water and use the reconstituted fluid as buttermilk. Another is to add the amount of powder that would make buttermilk with the water in the bread recipe.

Buttemilk powder can be purchased online from King Arthur Flour and other suppliers. The King Arthur Flour blog, discussing and promoting King Arthur Dried Buttermilk:

Use dried buttermilk as a substitute for the liquid buttermilk called for in your recipe. It’s simple as (buttermilk) pie: For every cup of liquid buttermilk, substitute 1/4 cup (30g) dried buttermilk plus 1 cup (227g) water (or milk).  Don’t worry about reconstituting the powder by stirring it together with liquid: Simply mix dried buttermilk into your recipe at the same time you add the flour, and add the liquid when the recipe says to add the buttermilk.


Dried buttermilk yields results nearly identical to liquid, with just two small differences: Baked goods made with dried buttermilk are slightly lighter in color than those made with liquid cultured buttermilk, and their flavor is a bit richer — more creamy-buttery than tangy.  

Another discovery: When replacing fresh buttermilk with dried, using milk in place of the water typically called for in this substitution gives baked goods even better texture and flavor, thanks to the additional milk solids, fats, and sugars. 

P.J. Hamel, September 14, 2022, King Arthur blog, Why you should be keeping dried buttermilk in your pantry

As of 2024, retail grocers in Victoria BC have skim milk powder for sale, but I have not seen whole milk powder or buttermilk powder on the shelves for years.

I have been able to get buttermilk powder in a local outlet of the bulk foods chain Bulk Barn (which also sells full fat milk powder and skim milk powder). Bulk Barn uses a serving size of 100 g. of buttermilk powder for the Food Facts label. 100 mg. contains 517 mg. of sodium. Bulk Barn suggests 25 g. to make 1 cup of buttermilk. This can be scaled to 28 g. of powder in 1 ⅛ cups of water. These are normal liquid quantities in recipes for medium loaves, in bread machine terms.

Fluid dairy buttermilk, reconstituted buttermilk and buttermilk powder added as a bread ingredient before mixing all produce similiar loaves.

A “1 cup” serving of Island Farms buttermilk contains 270 mg of sodium. “1 cup” of buttermilk made with 25 g. of Bulk Barn Buttermilk powder (and 1 “cup”) of water contains just under 260 mg. of sodium.

Substitution for buttermilk powder

Some internet resources suggest that mixing cream of tartar with skim milk powder, produces a powder that can be substituted for buttermilk powder. I am skepical in the absence of a serious scientific explanantion and test/experimental evidence:

  • Would adding cream of tartar (or one of the other acids) to a cup of reconstituted skim milk work – skim milk is very low in butterfat – make buttermilk that compares to dairy buttermilk; and
  • Doesn’t the cream of tartar, added as a powder to the dry dough ingredients (and not to the fluid milk) act like vinegar or other acids that relax dough – affecting the gluten and producing soft crumb.


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