Bitto can be a semi-hard or a hard cheese, depending on how long it was aged. Bitto Cheeses are sold anywhere from 40 days to 3 years in age.
When young, the cheese is called "giovane" (which means "young" in Italian.) It is soft, white-coloured and has a sweet taste similar to a gruyère. As it ages, it gets crumbly and small white dots appear on the rind. After a year of aging, it is yellowish, with a sharp taste, and is as hard as Parmesan, and can be used for grating.
It is made in the Valtellina area of Lombardy, Italy, as well as in the Albaredo, Bitto and Gerola valleys of Lombardy. It is produced both by small producers and larger factories.
It is made from whole cows' milk with a small portion of goat's milk, which makes for a stronger taste. Traditional makers will use up to 20% goat's milk; larger producers will use only up to 10%.
Bitto Cheese is made from March through to November. The milk is heated to 95 to 99 F (35 to 37 C), and stirred while it is heating. Calf's rennet is added to curdle the milk, and the heat is raised to 122 to 125 F (50-52 C.) The curds are stirred as they form, then are collected and put in moulds. The curd is pressed for 24 hours, then the nascent cheeses are salted on both sides, The cheeses are then matured for 40 days at 54 to 61 F (12 to 16 C.) At that point, they can be sold as "young" cheeses, or kept to age longer.
Traditional makers of Bitto start the cheese processing right in the pastures where the milk is collected, in stone huts with makeshift roofs. Milk that is just minutes old is put into copper pots over a fire. They make ricotta from the left-over whey. Traditional makers age Bitto Cheese for a minimum of 70 days. They start the aging of the cheeses up in pastures on the slopes on stone shelves, then the cheeses are sent down to cheese cellars in the valleys for their final maturing.
Bitto Cheeses will be 12 to 14 inches (30 to 35 cm) wide, and 4 to 4 3/4 inches (10 to 12 cm) tall. Some makers will produce cheeses between 12 and 19 inches (30 and 50 cm) wide and 3 to 4 inches thick (3 to 10 cm), weighing between 17 ½ and 55 pounds (25 kg.) Overall, depending on the size of the cheese, the weight ranges between 22 and 65 pounds (10 to 30 kg.)
Bitto Cheese, as made by traditional makers, obtained its DOP in 1996.
Bitto is presumed to come from the Celtic word for eternal, "bitu", named for the Bitto river, Italy.