To make Gruyère, raw unpasteurised milk is heated to 34 °C (93 °F) in a copper vat and then curdled by the addition of animal rennet. The curds are cut up into pea-sized pieces and stirred, this releases the whey. The whey is a by-product that is normally fed to the livestock.
The whey is strained, and the curds placed into moulds to be pressed. After salting in brine and smeared with bacteria, the cheese is ripened for two months. The Gruyère matures at room temperature, generally on wooden boards and is turned every couple of days to ensure even moisture distribution. Gruyère can be matured for 5 to 12 months, with the long maturing time producing cheese with an intense flavour.
In 2001, Gruyère gained the Appellation d’Origine Controlee status, stipulating that all Gruyere cheese must be stored in cave-like cellars where the humidity is no less than 94% and that the cave temperature must be between 13 and 14 degrees centigrade. Since then, the production and the maturation process has been passed into Swiss law, so that all Swiss Gruyère producers must follow these rules.
However, the Gruyère Premier Cru is a special cheese. It is produced and matured exclusively in the canton of Fribourg and matured for 14 months. It is the only cheese that has won the title of best cheese of the world at the World Cheese Awards four times: in 1992, 2002, 2005, and 2015