How Parmesan is made

Mix last night with this morning

Whole milk from the morning milking is blended with naturally skimmed milk from the evening before. The result is a part-skim mixture, and it is not pasteurized.

Warm it in copper vats

The milk is pumped into copper-lined vats, which heat evenly and add copper ions to the mix. Starter whey carrying heat-loving bacteria goes in, and the milk is brought up to a gentle warmth.

33 to 35 °C

Set and shatter the curd

Calf rennet turns the milk to a gel in a few minutes. Machines then break the gel into pieces about the size of rice grains.

10 to 12 minutes to set

Cook the grains hot

The cheesemaker raises the temperature with great care, then lets the grains settle to the bottom of the vat as a single mass.

55 °C, settle 45 to 60 minutes

Lift out two wheels

The settled curd is gathered in muslin, cut in two and dropped into molds. Each vat holds 1,100 liters of milk and yields two wheels, each starting at about 45 kilograms of curd. A belt pressed around each wheel stamps in the dairy number and date.

Float in salt brine

Wheels sit in tanks of brine saturated almost to the limit with salt. Salt is the only seasoning, and the wheels soak it up slowly.

20 to 25 days

Age on wooden shelves

Wheels move to aging rooms with shelves stacked 24 high. Every seven days each wheel and its shelf are cleaned and the wheel is turned.

at least 12 months

Tap every wheel

At 12 months a trained grader taps each wheel with a small hammer and listens for hidden cracks and voids. The sound sorts wheels into three grades, and only the top grade gets the official brand.