Our grandmothers knew the art of fermentation before it became a restaurant trend. Fermented drinks and dairy might be growing in popularity among the health conscious, but in most of the African food cultures fermented diary has been part of the regular diet for centuries.

One example is fermenting milk to make healthy homemade sour milk, amaSi (sour clotted milk) and yoghurt. While yoghurt is made by adding yoghurt cultures to induce a bacterial fermentation process, sour milk and amaSi are left to go sour naturally - although edible acidic substances such as vinegar or lemon juice can be added to speed up the process. 

Sour milk is not to be confused with buttermilk. Buttermilk is the end product of the butter-making process, when cream is churned to separate the milk solids (buttercream) from the milk liquids (buttermilk).

Sour milk and buttermilk  can however substitute each other in a recipe. Sour milk has a more acidic taste versus buttermilk's creamer taste. In South Africa sour milk, amaSi and buttermilk are used in heritage recipes such as buttermilk pudding, buttermilk rusks and Umphokoqo.

A few interesting notes from history:

• Jan van Riebeeck first mentioned buttermilk in his journal on 28 Desember 1652, when it was provided to patients at the Cape.
• Soldier and later schoolmaster at the Cape O.F. Mentzel (1733-1741) mentioned that farmers were permitted to sell buttermilk to patients and that in stead of wine, buttermilk was enjoyed at the family table.
• A healthy favourite in the earlier days of the Cape was a drink consisting of freshly chopped wood sorrel mixed with buttermilk.  
• A handwritten recipe for Kandeel by Mrs Letta Meiring, dated 1856, read as: "Buttermilk thickened with flour and sweetened with sugar."  It was her husband's favourite breakfast.
• Another Cape visitor, the Swedish botanist Thunberg (1772) mentioned that the Koikoin enjoyed sour milk in bags made out of animal skin.

Patience is important when trying the traditional method for making amaSi using spontaneous fermentation. Luckily one can nowadays conveniently buy amaSi from your local supermarket to use in Chef Eric's recipe for a delightful and versatile amaSi curd cheese.

amaSi curd cheese recipe

Serves 10

1l amaSi (soured milk)

Pour the amaSi into a clean muslin cloth, tie it at the top and hang it over the kitchen sink on the faucet or on a hanger with a dish underneath to catch the whey. Leave to drip out for 24 hours. Untie the cloth and scoop out the delicious curd cheese inside.

When straining the curd, the healthy nutrient-rich whey can be collected and used to add taste and nutrients to smoothies, to ferment vegetables, or add to your compost heap.

When the sour milk is strained the curd (maas) can be used as is or flavoured with herbs and spices.

The result is a versatile, soft, fresh cheese.

We serve it with a slice of freshly-baked baked seed loaf (Grandma's Loaf Recipe) and a glass of La Motte Sauvignon Blanc.

Try the following alternatives:

Stir in nuts, dried fruit or dried herbs into the maas at the start of the process

Serve with nut granola for a deliciously different breakfast.

Add amaSi to your porridge (traditional in phutu & umphokoqo) - it adds a delicious sourness and has a GI-lowering effect.