The King of Cheeses.
Parmigiano-Reggiano is made from unpasteurized cow's milk. The whole milk of the morning milking is mixed with the naturally skimmed milk (which is made by holding milk in large shallow tanks to allow the cream to separate) of the previous evening's milking, resulting in a part skim mixture.
Traditionally, cows have to be fed only on grass or hay, producing grass fed milk. Only natural whey culture is allowed as a starter, together with calf rennet. The only additive allowed is salt, which the cheese absorbs while being submerged for 20 days in brine tanks saturated to near total salinity with Mediterranean sea salt. The product is aged an average of two years. The cheese is produced daily, and it can show a natural variability.
The average Parmigiano-Reggiano wheel is about 18–24 cm (7–9 in) high, 40–45 cm (16–18 in) in diameter, and weighs 38 kg (84 lb).