Treviso Radicchio

Radicchio Rosso di Treviso is a chicory, Cichorium intybus, protected as an IGP since 1996. The rules cover two distinct products under one name: Precoce, the early type, and Tardivo, the late one.

The Precoce reaches the market from September. It has a full, closed head with broad fleshy leaves, deep red with a white midrib, and a moderate bitterness. It is blanched in the field, either by tying the leaves shut or covering the plant so the heart sees no light.

The Tardivo is something else entirely. The head is open, the leaves narrow and elongated, curving inward like claws; the white rib is thick and makes up most of the bulk; the blade is thin and wine-red. It snaps like celery, tastes sharply bitter, and keeps its long taproot attached and whittled to a point.

That shape does not occur in nature. It is the result of forcing and blanching, a post-harvest process that creates the vegetable rather than finishing it. Skip the process and you have a greenish, inedible chicory.

A third, frequently confused product sits alongside them: Variegato di Castelfranco IGP, a separate designation, which forms a pale rose-shaped head speckled with red and purple.

The bitterness in all of them comes from chicory's sesquiterpene lactones, chiefly lactucopicrin, and concentrates in the green parts and outer leaves.

Clean, assertive bitterness with a mineral edge, closer to Belgian endive than to any lettuce, but sharper and much crunchier. The white ribs are watery, sweet and almost saline; the red blades carry most of the bitterness.

Grilled, it changes completely: the sugars in the rib caramelise, the bitterness recedes, and the charred tips taste nutty. Cooked into a risotto it turns earthy and slightly sweet, and it stains the rice a dusty violet-pink.

The Precoce is milder, softer and juicier; the Tardivo is the one worth eating raw.

Raw is the Treviso default: quarter the head lengthwise, dress with good olive oil, salt and a little vinegar, or pour over a warm dressing of pancetta rendered and deglazed with vinegar. The fat softens the bitterness without cooking the leaves.

Grilling is the signature preparation. Halve the heads, oil and salt them, and put them on a very hot grill or griddle for a few minutes a side, until the ribs take colour and the tips char. Do not cook it long: it wilts and turns sour.

Beyond that, risotto: add it halfway through and finish with butter and Grana, or a spoonful of gorgonzola; pasta with radicchio and sopressa; whole leaves fried in batter; braised in the pan with beans and served with polenta.

Two rules. Do not soak it for long, or the ribs go limp. And manage the bitterness with fat, salt and sweetness (butter, pancetta, blue cheese, walnuts, a drop of balsamic) rather than with longer cooking, which makes it worse.

The taproot is edible and is the best part: peel it, slice it thin, and eat it raw.

Treviso is a winter vegetable and behaves like one: it wants cold and dark, which in a domestic kitchen means the salad drawer of the fridge. Keep the head whole and unwashed, wrapped loosely in a sheet of paper or a paper bag rather than sealed plastic, which traps the moisture the leaves give off and makes the ribs slick. Whole and unwashed, the Tardivo holds a week to ten days; the Precoce, softer leaved, more like four to six days. Wash it only at the moment of cooking.

The change is water loss. The white ribs lose turgor first, so the snap goes and the leaf bends; then the red edges darken towards brown and the cut base oxidises and dries. Bitterness increases as the head ages and the sugars go. Trimming a thin slice off the base and standing the head briefly in cold water restores some crispness. Do not freeze it raw, because the cell walls collapse and it thaws to a wet rag; if you want to keep it, grill or braise it first and freeze the cooked result, which holds two to three months.

In most shops abroad, radicchio means the round purple ball, which is Chioggia, a different variety. Treviso is elongated. The Tardivo is the one to know: separate long narrow leaves, deep wine red with a broad white central rib that takes up most of the leaf, tips hooked and curled backwards, and the taproot left on and trimmed to a white point. It snaps rather than bends. The Precoce is a closed elongated head that looks like a red romaine, softer leaved and less crunchy.

Both carry Radicchio Rosso di Treviso IGP on a paper tag or sleeve with the consortium mark, and the tag says Tardivo or Precoce. Season is a check in itself: Tardivo appears from November and runs to February or March, so a Tardivo in July has come from somewhere else. Do not confuse it with Variegato di Castelfranco IGP, which is a cream coloured rosette speckled with red. Price follows the labour, since Tardivo is forced in spring water for weeks: expect $8 to $16 a pound abroad against $3 to $5 for Chioggia.

Outside Italy this is a short, specific season: real Tardivo appears in December and disappears by early February, so it is a December-January purchase or nothing. In the US, Italian greengrocers and specialists such as Eataly and Gustiamo bring it in for a few weeks, and some farmers' markets in California and the Pacific Northwest now grow forced Treviso-type chicories. In the UK, Natoora supplies it to restaurants and sells direct in season, and Italian delicatessens carry it around Christmas.

Check for the taproot still attached and trimmed to a point, narrow leaves curving inward, a thick glossy white rib and no green at the base. A rib should snap cleanly when bent.

The crate or band should carry the EU IGP mark, the full designation with Precoce or Tardivo specified, and the consortium reference.

In Italy expect 8 to 15 euros a kilo locally and 12 to 20 outside the region, roughly 6 to 11 dollars a pound, or 12 to 20 pounds a kilo abroad. Precoce is a third of that. A trimmed head weighs 150 to 300 grams.

Dosson di Casier, just outside Treviso, in December, for the main show of the season: growers' stalls, field kitchens grilling it over coals, and risotto served all day.

Zero Branco, Preganziol and Rio San Martino di Scorzè run their own exhibitions and radicchio dinners between December and January. These are the weeks when forcing sheds open to visitors, and thirty seconds looking at heads standing in the dark in running spring water explains the price better than any label.

Treviso itself, where every osteria in the centre puts it on the menu from December: grilled, in risotto, fried in batter, and paired with sopressa or with baccalà.

Castelfranco Veneto, a short drive west, for the Variegato, whose season runs at the same time.

Go in the second half of December. The Tardivo is at its peak, and the fog over the plain is part of the experience.