What is the difference between arborio, carnaroli and vialone nano?

Risotto rice is not one thing. The bag in the supermarket might say arborio, carnaroli, vialone nano or simply "risotto rice", and they behave differently in the pan. None is wrong. The differences come down to how much the grain holds its shape, how much starch it gives up, and how quickly it cooks.

What they have in common

Wikipedia's risotto entry describes risotto rice as a starchy, round, medium- or short-grain white rice, stickier than long-grain types. It names Carnaroli, Maratelli and Vialone Nano as the varieties usually considered the best, and also notes you should not rinse risotto rice, since washing takes away the starch that makes the dish creamy. That starch, released as the rice cooks in stock, is what makes risotto creamy without any cream.

Carnaroli: the forgiving one

Carnaroli was bred in Italy in 1945 and is grown in the provinces of Pavia, Novara and Vercelli, according to Wikipedia's carnaroli entry. It is a longer grain than arborio, and the same entry credits its firm texture to its greater amylose content, which helps it hold its shape through slow cooking.

In practice, this is why many cooks call it the safest bet. Carnaroli gives you a good creamy sauce while each grain stays distinct with a little bite in the centre. Leave it a minute too long, or get distracted by a guest, and it forgives you. It also behaves well the next day as arancini.

Vialone nano: small, quick and very creamy

Vialone nano is a medium-grain semifino rice bred by crossing Vialone with a variety called Nano, and grown in Italy since 1937, according to Wikipedia's vialone nano entry. Its Veronese form has protected geographical indication (Riso Nano Vialone Veronese IGP), with cultivation limited to municipalities in the province of Verona.

The grain is rounder and smaller than carnaroli. It absorbs a lot of liquid and cooks a little faster, giving a looser, wavy risotto, the style the Veneto calls all'onda. Wonderful with spring vegetables, peas and anything delicate. It is a touch less patient than carnaroli, so taste early.

Arborio: the one in every shop

Arborio is named after the town of Arborio in Piedmont, and Wikipedia's arborio entry describes its rounded grains as firm, creamy and chewy when cooked. It is the variety most widely available outside Italy.

Arborio makes a lovely risotto, but it gives up its starch readily and softens quickly at the end. That means a creamier, stickier result and a smaller window between perfect and porridge. It is also very good for baked rice dishes and rice pudding. If arborio is what you have, use it; just start tasting earlier and pull it off the heat while it still has a firm heart.

Which to buy first

• One bag only: carnaroli. The most forgiving and the most versatile.
• Spring risotto, peas, asparagus, herbs: vialone nano, for that loose, soft texture.
• Whatever the corner shop has: arborio, cooked with a careful eye.

Look for "superfino" or "semifino" on Italian packets, a sign of grain size, and a recent packing date. The rest is in the cooking, and the debate about stirring is its own page: do you really have to stir risotto all the time.

How to tell when it is ready

Whatever the variety: bite a grain. It should be tender all the way through with just a tiny firm point in the middle, and the risotto should flow slowly when you tilt the pan. Then off the heat, butter and cheese, lid on for a moment, and to the table. Risotto waits for nobody.