Herrgårdsost starts as part-skim milk, usually pasteurized. Bacterial starters are introduced to the milk, including lactic acid bacteria, 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 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. 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.

he two most popular varieties in Norway are Gudbrandsdalsost, which means ‘cheese from the Gudbrandsdal’, from the Gudbrands valley (made from 24 % goat’s milk and cow’s milk), and the more traditional version geitost, which simply means ‘goat cheese’, and which is wholly or in part made from goat’s milk. There are also regional varieties, which vary both in colour and taste, depending on how much caramel they contain.

Geitost has a strong, sweet, yet somewhat sharp flavor with notes of caramel and goat’s milk, while Gudbrandsdalsost is similar but more mellow in taste. The two varieties are often used as an open sandwich topping, on bread, malt loaf, or together with lefse, a traditional soft Norwegian flatbread. Brunost and lefse are used in some areas as a side dish to lutefisk, a traditional dish made from stockfish.

Geitost is also used in game sauces, often together with juniper berries. It lends such sauces a more subtle, caramel taste.