Quark cheese, also called curd cheese, is a type of soft, white, un-aged cheese originating in Central Europe. It is similar to other un-aged cheeses, such as farmer's cheese, French fromage frais, South Asian paneer, and Mexican queso blanco. Quark is typically low in fat and a good source of protein and vitamin B12. It has been enjoyed by Germanic people since at least the first century CE, when Roman author Taciturn described it in his writings.
This type of cheese is acid set, meaning that it is the addition of lactic acid bacteria that turns the milk into cheese. In the US, the milk used to make quark must be pasteurized, as the cheese is not aged before it is eaten. Quark cheese is traditionally made without rennet, an enzyme complex naturally found in the mammalian stomach and used in much cheese production, although some modern versions may be because it results in a firmer product. Other variations add cream, spices, or fruit to the mixture.
When quark cheese is made with rennet, most or all of the whey, the liquid component left over in cheese production, is drained off. Traditionally, the cheese is hung in a porous cheesecloth, allowing the whey to drip out as the cheese forms. This process creates a wedge-shaped cheese. Today, the whey may be removed with a centrifuge in a factory.
Quark varies in firmness depending on how it is made, and different types are suited to different culinary uses. Rennetless quark, common to Germany, is very soft, similar in texture to sour cream, though slightly drier. It is continually stirred during production and sold in tubs with most of the whey remaining. This type of cheese may be used as a spread, served with fruit, or used to make cheesecake.
In Eastern Europe, quark is drier and firmer and may be used in salads and sandwiches or to make cheesecake. This type is sold in Canada as baking cheese. Quark is not common outside of Central and Eastern Europe, although a few dairies in the United States also make it.