Herrgårdsost is a semi-hard Swedish

Sweden

Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

 cheese

Cheese

Cheese is a generic term for a diverse group of milk-based food products. Cheese is produced throughout the world in wide-ranging flavors, textures, and forms....

 made from cow

Cattle

Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...

's milk

Milk

Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...

. Made since the 1890s, it is still popular in Sweden today. The aged cheese has a mild, sweet, nutty flavor and small round holes. The cheese is usually manufactured in wheels about 40 centimetres in diameter and 12 centimetres wide, weighing around 14 kilograms.

Herrgårdsost starts as part-skim milk, usually pasteurized

Pasteurization

Pasteurization is a process of heating a food, usually liquid, to a specific temperature for a definite length of time, and then cooling it immediately. This process slows microbial growth in food...

. Bacterial

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 starters are introduced to the milk, including lactic acid bacteria

Lactic acid bacteria

The lactic acid bacteria comprise a clade of Gram-positive, low-GC, acid-tolerant, generally non-sporulating, non-respiring rod or cocci that are associated by their common metabolic and physiological characteristics. These bacteria, usually found in decomposing plants and lactic products, produce...

, which acidify the milk, and propionic bacteria, which are responsible for producing the carbon dioxide that creates the holes. The soured milk is curdled with rennet

Rennet

Rennet is a complex of enzymes produced in any mammalian stomach to digest the mother's milk, and is often used in the production of cheese. Rennet contains many enzymes, including a proteolytic enzyme that coagulates the milk, causing it to separate into solids and liquid...

 and heated to no higher than 43°C. The whey is drained and the curd is pressed, forming a wheel, which is then salted in brine. Around two weeks later the cheese wheels are coated in wax

Wax

thumb|right|[[Cetyl palmitate]], a typical wax ester.Wax refers to a class of chemical compounds that are plastic near ambient temperatures. Characteristically, they melt above 45 °C to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents...

. They are aged in this state usually for another three or four months, but often up to 12 or even 24 months.

The finished product is 39.5% water, 29% fat, 27% protein, and 1.5% salt.