The provisions stipulated in the production specification include a requirement that the milk must be cow's milk. During the summer grazing period in Alpine pastures, the cows must be fed on fresh grass, and when stabled, they must be fed mainly on hay and silage, up to a maximum of 15 kg (33 lb) per head. If necessary, the milk may be lightly skimmed to regulate the fat content to between 3.45 and 3.6 %. After the addition of calf's rennet, it is processed at a temperature of 32-33 °C (90-91 °F). After a period of between 20 and 27 minutes, the milk curdles, after which the cheese curds are broken to the desired size, stirred and pressed; then the rounds are set aside in a controlled environment (until the acidity reaches the right level) and salted by immersing the rounds in brine. They are then left to mature on wood boards. The traditional method of processing requires the whole rounds to be turned and the surfaces washed with a weak saline solution at least twice a week. Local microflora are added to the saline solution used to wash the cheese during the first two or three weeks of maturing. These microflora include various strains of aerobic bacteria of the Arthobacterium subspecies and of the Brevibacterium breed. The particular strains used during this stage give the characteristic yellow-orange-brown coloring of the cheese surface, as well as the aroma and taste characteristic of Stelvio or Stilfser cheese. This coloring is natural, and stems from the proliferation of these strains of local bacteria, which are unique and exclusive to the area.
The cheese is ready for consumption after maturing for a minimum of sixty days. The cheeses are cylindrical with flat or almost flat sides and a straight or slightly concave heel. Each cheese measures between eight and ten kilograms (18-22 lb) in weight, with a diameter of between 36 and 38 cm (14-15 in) and a height of between 8 and 10 cm (3-4 in). The fat content in dry matter is at least 50 % and the moisture content does not exceed 44 %. The rind must be of a yellow-orange to orange-brown color. The cheese is compact, pliable and springy in texture, pale, straw yellow in color, with irregular, small to medium-sized eyes.
Stelvio or Stilfser cheese is sold either in whole rounds or portions. Whole rounds are sold with the designation of origin label, which is affixed only after it has matured for 60 days, and the stamp indicating the batch, date of production and producer code. Only after having being labeled with the Designation of Origin label are the rounds of cheese produced in accordance with these specifications cut into portions for sale. Stelvio cheese may also cut into portions outside the PDO defined area. Portions of Stelvio or Stilfser cheese are sold with a label, which is affixed only after the whole round has matured for 60 days, identifying the designation of origin, with an adhesive label which is affixed to the portion by the authorized producer during the packaging stage, or with a pre-printed wrapping bearing the Stelvio or Stilfser PDO. Products for sale bear the specific label denoting the designation of origin. The designation of origin label contains the words Stilfser/Stelvio in red lettering, as laid down in the production specifications.