Trevi Black Celery

Sedano nero di Trevi is a local landrace of Apium graveolens grown exclusively on the plain at the foot of Trevi, a hill town in the province of Perugia, Umbria. It is a Slow Food Presidium and a recognised traditional product of the region.

The name misleads, so deal with it first. The plant is not black. The upper stalks and leaves are a very dark green with a bluish cast; the base, kept covered with earth as the plant grows, blanches to pale green or near white. In the local dialect the words for dark and black are the same, and the name stuck.

The scale is the second surprise. A mature plant stands eighty centimetres to a metre and weighs one to two kilos, with stalks four to five centimetres wide and genuinely thick and fleshy. This is not a bunch of celery: it is a vegetable you cut into pieces.

The trait that explains everything else is the absence of strings. The stalks carry none of the fibrous bundles that force you to peel ordinary celery, and they are solid rather than hollow. You can eat them raw with no preparation at all, and that is precisely why the local kitchen treats them as a container to be stuffed rather than an aromatic for the stock pot.

Sweet, clean and juicy, with far less of the soapy, aggressive green note that puts people off celery. There is a mineral edge and a faint aniseed lift, and no bitterness at the base at all, because the blanching removes it.

The texture is the thing. A stalk snaps cleanly, with an audible crack and nothing stringy left behind, and the flesh is dense enough to hold a filling through frying and twenty minutes in sauce. Raw, it eats like a very good crisp apple stalk; braised, it holds its shape where a supermarket celery would collapse.

The leaves are strongly aromatic (closer to lovage than to ordinary celery tops) and are used rather than discarded.

The dish Trevi built around this vegetable is stuffed celery, and the string-free stalk exists to make it possible. Cut the ribs into eight to ten centimetre lengths, blanch two minutes to soften them, dry them, and fill with minced beef and pork, chicken livers, egg, parmesan and nutmeg. Press two pieces together into a parcel, flour them, dip in beaten egg and fry. Finish for twenty minutes in a light tomato sauce and serve with grilled Umbrian sausage.

Raw needs no recipe. Cut the ribs into batons and dip them in new-pressed Trevi olive oil with salt and black pepper. It is the fastest way to understand why this celery has a name of its own.

Braised, it behaves far better than ordinary celery. Quarter a whole head lengthways, brown it in olive oil, add stock and cook covered for thirty minutes: it holds together and turns silky. Gratinated with béchamel and parmesan is the Sunday version.

Keep the leaves. They are strongly aromatic, close to lovage, and belong in stock, in bean and lentil soups, or chopped raw over a lentil purée. The cleaned root end makes better vegetable stock than you would expect.

Whole, with the roots trimmed but still attached, it keeps about a week in a cool damp room, wrapped in a wet cloth or standing in two fingers of water like a bunch of flowers. That is the household method and it beats refrigeration. In the fridge, rolled in a damp tea towel in the vegetable drawer, it holds eight to ten days. Avoid a sealed plastic bag, because condensation gathers at the cut base and the tissue there softens and darkens first.

Over those days it loses water: the ribs bend instead of snapping, the outer ones go ridged and the leaves yellow. Limp ribs are not the end: cut into batons and left in iced water for an hour, they draw the water back and regain the snap. Freezing needs two minutes in boiling water and a plunge into ice first, after which it holds six months, but what comes out belongs in broths and braises rather than raw or stuffed: the rib no longer has the rigidity to hold a filling. The leaves dry in the shade or a low oven and keep all winter.

Size comes first. A black celery plant stands eighty centimetres to a metre and weighs one to two kilos, so a half-kilo head, however dark, is not this. Then the colour, which should work in two registers: very dark green with a blue cast at the top and through the leaves, pale green to almost white at the base where the earthing up did its job. A uniformly light plant was never earthed up, and a uniformly dark one was not earthed up enough.

The test that settles it is the strings. Snap a rib in half rather than cutting it: it should break clean with an audible crack and leave no threads between the halves, and any filaments mean ordinary celery. In cross-section the rib should be fleshy and solid rather than the thin hollow crescent of a supermarket stick, and that thickness is what lets it be stuffed. Last, the calendar. Trevi black celery exists from October to the end of November, and in any other month the name covers something else. Outside Umbria you will not find it, and Pascal celery is what the shops have.

Honestly: only in Umbria, and only in autumn. Roughly ten hectares are grown, the harvest runs six weeks, and effectively all of it is sold at farm gate, at markets in Trevi, Foligno and Spoleto, and at the October festival. Nothing is exported.

In Italy it is priced by the plant rather than the kilo because the heads are large: 4 to 10 euro each, working out at roughly 3 to 6 euro per kilo. The festival on the third Sunday of October is the best place to buy, with growers selling plants lifted that morning.

Outside Italy, buy for the characteristics. In the UK, Fenland or trench celery from October to December is the closest thing available, at 6 to 12 pounds per kilo where you can find it. In the US there is no direct equivalent, so take the largest, thickest-ribbed green celery you can find and peel the strings off. Expect 5 to 9 dollars per pound for anything sold as heirloom or trench-grown.

Whatever you buy, look for solid ribs rather than thin hollow crescents, and snap one: a clean break with no strings is the whole point.

Trevi, in the province of Perugia, on the third Sunday of October, when the black celery and sausage festival takes over the town. Stuffed and fried ribs, grilled sausage, growers selling plants pulled that morning, and the new olive oil pressing starting in exactly those weeks.

The town earns the trip anyway: a vertical medieval borgo on a spur above the Umbrian valley, with a museum devoted to olive culture and a view that explains without words why oil is taken seriously here.

Five kilometres north are the Clitunno springs, the resurgent water that feeds the plain the celery grows on, praised in turn by Virgil, Byron and Carducci, with a small Lombard temple alongside.

The wider valley packs a lot into thirty kilometres: Foligno, Spoleto, Bevagna, and Montefalco for Sagrantino. The second half of October is the moment: celery at its peak, olives going into the mill, the vintage just finished.