“Yes please!” I said when a friend asked if I’d like a fresh, daily supply of yoghurt. She took a jar covered in cheesecloth out of her kitchen cupboard, and dipped a fork into the contents: creamy, thick yoghurt. She fished around with the fork and lifted out a cauliflowerish lump: kefir.
“All it takes is a piece of this in half a jar of milk, at room temperature, overnight in a dark place. And you have a fresh, probiotic culture every day. It keeps on going,” she said.
Kefir ‘grains’ are lumps of bacteria and yeast, that co-exist in a mesh of proteins, fats and carbohydrates. How are they made? By following a recipe that sounds something like a witch’s magic potion.
The process starts out when sheep’s intestinal flora are mixed with milk in a goat’s hide bag and left at room temperature for days. Each time the milk coagulates, it is poured out, leaving a small amount in the bag, and more fresh milk is added. After about 3 months, a layer of complex carbohydrates will form on the bag – the main carbohydrate being kefirin. This is released by two strains of Lactobacillus bacteria – a name we know from supermarket probiotic yoghurts.Once this layer is formed, it can be used to ferment fresh cow, sheep and goat’s milk, and the lump grows and divides over time. This little symbiotic community of bacteria and yeast, living in an apartment block of kefirin, works by fermenting lactose in the milk, producing carbon dioxide, alcohol (just 1%) and a sour, chunky, yoghurt-like drink. And since most of the lactose is broken down, it’s a good drink for lactose-intolerant people.
Who on earth figured this complicated, slightly weird formula out? Shepherds in the North Caucasus region, north-east of Turkey, discovered that milk in their leather pouches would ferment into a bubbling, sour curd, and drank it up, while saving some to make more.
Luckily today we don’t have to go in search of sheep’s gut contents, nor wear leather pouches attached to our belts, to create this healthy drink. Because kefir grains can be freeze-dried or frozen, they can be bought. There are several yogurt makers that can keep the milk at the right temperature overnight.
If you like yoghurt, it’s worth a try. The grains can also ferment coconut milk, soy milk and rice milk. You can make sourdough bread with it, since it contains yeasts. Just make sure that you don’t seal the jar – a layer of cheesecloth secured over the top is enough – and don’t fill it up: the escaping carbon dioxide needs space.