Kefir Fermentation. Kefir is a type of fermented milk, usually cow's milk. It has an acidic, almost citric, sour taste. Kefir contains kefir grains, live bacteria, and yeast.

The budget supermarket is now selling a large kefir drink, which is also known for its immune system and gut health-boosting properties. Priced at £1.99, shoppers can snap up a 750ml bottle of ...

So, while kefir is quite different from typical yogurt, the gulf may not be as large as the difference between skyr and Greek yogurt. For more food and drink goodness, join The Takeout's newsletter .

Kefir is traditionally made by adding kefir grains to milk or sugary water (1 teaspoon of grains to 1 cup of liquid) and letting the mixture ferment at room temperature for about 24 hours.