Ingredient

Parmesan

Parmesan is aged for a year or more, and in that time enzymes break its proteins down into free amino acids. That is why a small amount adds so much savoury depth, and why it tastes so different from a young cheese.

Why it tastes the way it does

Long ageing does two things. It drives out moisture, concentrating everything, and it lets enzymes break the milk proteins into free glutamates and other amino acids — the compounds the tongue reads as savoury.

That is why parmesan works as a seasoning rather than only as a cheese, and why a spoonful transforms a soup or a pasta sauce. It is also why the crystalline crunch appears in a well-aged piece: those crystals are amino acids that have come out of solution, and they are a sign of good ageing rather than a fault.

Parmigiano Reggiano is the protected original, aged at least twelve months and usually longer. Grana Padano is similar and milder. Pecorino Romano is sheep's milk, saltier and sharper. All three do a similar job and they are not interchangeable in quantity — pecorino in particular is much saltier.

Using it

• Grate it fresh. Pre-grated parmesan is coated in anti-caking starch and has lost most of its aroma. A block keeps for months and is cheaper.
• Add it off the heat. It does not melt smoothly on its own — the protein is too tightly bound — so in a sauce it goes stringy or grainy if boiled.
• Use it with a melting cheese if you want it in a smooth sauce. On its own it will not emulsify.
• Season afterwards. It is very salty, and a dish salted before the parmesan goes in is usually over-salted.
• Shave it with a peeler for salads, where the texture matters.
• Crisp it — a small mound grated onto a hot dry pan or a lined tray in the oven melts and sets into a savoury wafer.

The rind

Do not throw it away

It is the single most useful thing in this article. Keep every rind in a bag in the freezer.

In soups and stews

Drop a rind into minestrone, bean soup, tomato sauce or a braise. It softens, releases savour into the liquid, and is fished out at the end.

In stock

A rind in a vegetable stock adds a depth that vegetables alone cannot.

Grilled

Softened and browned, it becomes chewy and intensely savoury.

What it is not

Wax. Parmesan rind is the same cheese, dried and hardened, and is entirely edible.

Buying and storing

• Buy a wedge cut from a wheel rather than a pre-packed block if you can. Look for the pin-dot crystals and a slightly crumbly, granular texture.
• It should smell nutty and savoury, not sharp or ammoniac.
• Wrap it in greaseproof paper, then loosely in foil or a bag, and keep it in the fridge. Airtight plastic makes it sweat and go slimy.
• It keeps for months. Surface mould can be cut off generously on a hard cheese like this.
• Grated parmesan freezes well, and the rinds freeze indefinitely.

Common questions