Kasseri (Greek Κασέρι; or in Turkish kaşer, kaşar) is a medium-hard pale yellow cheese made from unpasteurized sheep milk with very little, if any, goat's milk mixed in. The cheese is found in Greece, Bulgaria and Turkey. An alternative way of making the cheese uses cow-milk.
It is a soft textured, stringy rather than crumbly, chewy, hard-rind cheese and belongs to the pasta filata family of cheeses, like Provolone or Mozzarella. The use of fresh unpasteurized milk is necessary to obtain the correct flavor and texture, and aging of at least four months is required for the development of flavor. Aged kasseri faintly resembles Parmesan or Asiago but is not as creamy.
The name kasseri comes from Turkish kaşer, which in turn likely comes from Hebrew כָּשֵׁר (kosher). The lack of the use rennet during its production makes the cheese fit for the requirements of the Jewish law, as the cheese was invented in Edirne, Turkey, by the Jewish community of the town. However, the name is listed in protected designations of origin in the European Union under Greece as its origin. It is not to be confused with the Turkish province of Kayseri.