How is kaernemaelk made?

What is kaernemaelk?

Kaernemaelk (Danish kaernemaelk with the letter ae) is Danish buttermilk, a tangy, slightly thick drink and cooking ingredient used across Denmark and neighboring countries.

The traditional method

Historically, kaernemaelk was the liquid left over after churning butter from soured cream. The cream was left to sour, churned until the fat separated, and the remaining liquid was drunk. This gave a thin, sour drink.

The modern method

1. Start with skimmed milk: most cartons are made from fresh skimmed milk.
2. Add a culture: a lactic acid bacteria culture is added. The Danish Dairy Association says the same traditional culture is used for tykmaelk, ymer, creme fraiche and skyr.
3. Ferment: the culture sours the milk at a controlled temperature, giving acidity and a creamy body. A fermented-milk reference gives 20 to 22 degrees C as ideal for a DL-type starter, where some bacteria make acid and Leuconostoc adds flavor and aroma.
4. Cool and pack: it is chilled and sold in cartons.

Danish sources give about 0.5 percent fat, though one source gives 0.3, so check the carton.

Is it the same as buttermilk in the US?

They are similar: cultured, tangy and low in fat. Brands and labels differ, so check the product.

How is it used?

• Served cold as a drink.
• As the base of koldskaal, a chilled Danish buttermilk dessert soup.
• In baking, where buttermilk adds tang.

Can I make it at home?

For baking you can use a substitute such as milk with a spoonful of vinegar or lemon juice, but that is acidified milk and not true cultured kaernemaelk. A cultured version needs a starter culture; follow the instructions that come with it.