Acid-set or sour milk cheese is

cheese Cheese is a type of dairy product produced in a range of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk (usually the milk of cows, buffalo, goats or sheep). During prod ...

that has been

curd Curd is obtained by Denaturation (biochemistry), coagulating milk in a sequential process called curdling. It can be a final dairy product or the first stage in cheesemaking. The coagulation can be caused by adding rennet, a Kefir cheese, ...

led (coagulated) by natural souring, often from

lactic acid bacteria Lactobacillales are an order of gram-positive, low-GC, acid-tolerant, generally nonsporulating, nonrespiring, either rod-shaped (bacilli) or spherical ( cocci) bacteria that share common metabolic and physiological characteristics. These bact ...

, or by the addition of

acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

. This type of cheese is technologically simple to produce. When making soft acid-set cheese using bacteria, the coagulum results from production of lactic acid by the starter microorganisms. Cheeses can be classified according to a variety of features including ripening characteristics, special processing techniques (such as

cheddaring The manufacture of Cheddar cheese includes the process of ''cheddaring'', which makes this cheese unique. Cheddar cheese is named for the village of Cheddar, Somerset, Cheddar in Somerset in South West England, South West England where it was o ...

) or method of coagulation. Acid-setting is a method of coagulation that accounts for around 25% of cheese production. These are generally fresh cheeses like, queso blanco,

quark A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nucleus, atomic nuclei ...

and

cream cheese Cream cheese is a soft, usually mild-tasting fresh cheese made from milk and cream.Oxford English Dictionary Cream cheese is not naturally matured and is meant to be consumed fresh, so it differs from other soft cheeses such as Brie and Neuf ...

. The other 75%, which includes almost all ripened cheeses, are

rennet Rennet () is a complex set of enzymes produced in the stomachs of ruminant mammals. Chymosin, its key component, is a protease, protease enzyme that curdling, curdles the casein in milk. In addition to chymosin, rennet contains other enzymes, su ...

cheeses.

Ricotta Ricotta () is an Italian whey cheese made from sheep, cow, goat, or Italian water buffalo milk whey left over from the production of other cheeses. Like other whey cheeses, it is made by coagulating the proteins that remain after the casein h ...

and most other

whey cheese Whey is the liquid remaining after milk has been curdling, curdled and strained. It is a byproduct of the manufacturing of cheese or casein and has several commercial uses. Sweet whey is a byproduct resulting from the manufacture of rennet types ...

s are made by first heating the milk to between 90 and 92 degrees Celsius to create coprecipitation of

casein Casein ( , from Latin ''caseus'' "cheese") is a family of related phosphoproteins (CSN1S1, αS1, aS2, CSN2, β, K-casein, κ) that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of ...

and

whey protein Whey protein is a mixture of proteins isolated from whey, the liquid material created as a by-product of cheese production. The proteins consist of α-lactalbumin, β-lactoglobulin, serum albumin and immunoglobulins. Glycomacropeptide also m ...

before addition of lactic or

citric acid Citric acid is an organic compound with the formula . It is a Transparency and translucency, colorless Weak acid, weak organic acid. It occurs naturally in Citrus, citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, ...

Production

Rennet Rennet () is a complex set of enzymes produced in the stomachs of ruminant mammals. Chymosin, its key component, is a protease, protease enzyme that curdling, curdles the casein in milk. In addition to chymosin, rennet contains other enzymes, su ...

is also sometimes used in the processing of other fresh, soft cheeses like fromage frais, but it is not an essential ingredient and these cheeses can be produced by traditional methods without rennet or other enzymes. Ricotta is a high-moisture cheese, like cottage cheese, but it is not a pressed curd cheese. It can be made from

whey Whey is the liquid remaining after milk has been curdled and strained. It is a byproduct of the manufacturing of cheese or casein and has several commercial uses. Sweet whey is a byproduct resulting from the manufacture of rennet types of hard c ...

or a blend of milk and whey. Traditionally, ricotta was produced from the whey byproduct of

mozzarella Mozzarella is a Types of cheese#Semi-soft cheese, semi-soft non-aged cheese prepared using the ('stretched-curd') method with origins from southern Italy. It is prepared with cow's milk or buffalo milk, taking the following names: * or mozz ...

and provolone production, but modern techniques usually use whole milk (sometimes without any whey). Milk can be blended into the whey to improve curd cohesiveness, neutralize the acid in whey and increase yield. This mixture of milk and whey is heated before enough food grade acid is added to drop the pH to the needed level (this could be some type of

lactic acid Lactic acid is an organic acid. It has the molecular formula C3H6O3. It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as wel ...

acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main compone ...

). Whichever type of acid is used by the cheesemaker it is important to maintain correct pH levels for the sweetness of the cheese's flavor. Some methods of mass-produced cheeses will use food grade caustic soda to neutralize the acid of the whey, before heating the blend and adding the coagulating acid.

Regional varieties

In Germany the term ''Sauermilchkäse'' is usually applied to ripened acid-set cheeses only, but not to fresh cheeses. The various types of ripened sour milk cheese include: * Handkäse * Harzer * Nieheimer * Olomoucké syrečky (Olmützer Quargel) * Tyrolean grey cheese

References

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Production

Regional varieties

See also

References