Amasi (in Ndebele, Zulu and Xhosa), emasi (in Swazi), maas (in Afrikaans), or mafi (in Sesotho), is a thick curdled sour fermented milk product that is sometimes compared to cottage cheese or plain yogurt but has a much stronger flavor. A staple food in pre-colonial times, it is now a popular snack in South Africa and Lesotho.