🥣 Amasi

Amasi is a thick sour milk from southern Africa, popular in South Africa, Zimbabwe and Lesotho. In Zulu and Xhosa it is called amasi, in Afrikaans maas; similar products include madila in Botswana, mafi in Lesotho and mabisi in Zambia and Namibia. South African rules allow the word “maas” on the label to be replaced with “amasi” or “amazi”.

Traditionally, raw cow's milk is left to sour at room temperature for 1–3 days in a calabash, a bottle gourd or a clay pot; its own bacteria ferment it, the thin whey is drained off, and a thick sour curd remains. In laboratory experiments raw milk at 25–32 °C soured to a pH of about 4, with lactobacilli dominating among the bacteria. Commercial amasi is made differently: pasteurised milk is inoculated with Lactococcus lactis cultures and held for 12–18 hours at 20–30 °C.

Under South Africa's 2019 regulation, amasi, as a cultured milk, has to be acidic (pH below 4.6) and contain at least 10 million live lactic acid bacteria per 1 g, and it is not heated after fermentation. Full-fat maas contains from more than 3.3 to 4.5% fat; there are also high-fat, medium-fat, low-fat and fat-free versions. Amasi is eaten with pap, a maize porridge, or drunk.

Amasi or buttermilk, yogurt, kefir? Amasi is thick soured milk from southern Africa. Traditionally raw cow's milk sours by itself for 1–3 days in a gourd or clay pot and the thin whey is drained off, which is why it is thicker than plain clabbered milk. Commercial amasi is made from pasteurised milk with a Lactococcus lactis culture, not from a yogurt pair of bacteria or kefir grains. In South Africa the label may say “maas”, “amasi” or “amazi” for the same cultured milk.

On the pack look for “amasi”, “maas” or “amazi”: South African rules allow the three words for the same cultured milk. Next to it you will see a fat class, such as “full fat maas” or “low fat maas”. Choose a pasteurised product, because acidity does not replace pasteurisation. It is sold in African and South African food shops and in the chilled aisle of larger supermarkets that stock African products; keep it refrigerated.

Why it matters to you. Homemade amasi from raw milk carries risks: Mycobacterium bovis, the cause of bovine tuberculosis, survived in souring milk for at least two weeks at 20 °C, and E. coli O157:H7, once in the milk, survived in experiments even in acidic amasi. Acidity is no substitute for pasteurisation, so amasi made from pasteurised milk is the safer choice; look for the fat class on the label.