Citron of Santa Maria del Cedro

The citron is Citrus medica, the first citrus to reach the Mediterranean and one of the three ancestral species from which almost every other citrus descends. The fruit grown at Santa Maria del Cedro and the neighbouring towns on Calabria's Tyrrhenian coast belongs to the Liscia Diamante cultivar and is a Slow Food Presidium.

It is big and heavy, one to two kilos as a rule and up to three or four on the best trees, and structurally the opposite of a lemon. The yellow rind is very thin. Beneath it sits a white layer up to five centimetres thick, the albedo. At the centre there is a small core of intensely sour flesh with almost no juice.

That albedo is the product. In nearly every other citrus the white pith is bitter and thrown away; in a citron it is firm, crisp and faintly sweet, eaten raw in salad or candied. Calabrian candied citron has been going into Milanese panettone, Sicilian cassata and Neapolitan pastiera for well over a century.

Then there is the second use, which is not culinary and which kept the crop alive when the candying industry paid badly. In Jewish tradition the citron is the etrog, one of the four species used at the festival of Sukkot, and fruit intended for that purpose must meet exacting requirements. Each summer buyers and rabbis from Israel, the United States and Europe come to this coast to inspect fruit one by one. A specimen judged perfect can be worth hundreds of euro; the rest, the overwhelming majority, go back into the food chain.

Nothing like a lemon, and the surprise is how mild it is. The white pith eaten raw is crisp and watery with a faint sweetness and only a whisper of bitterness, closer to a firm cucumber or a raw water chestnut than to any citrus you have chewed by accident.

The yellow rind is where the aroma lives, and it is intense: resinous, floral, almost pine-like, far less sharp than lemon zest and much more perfumed. Grated over anything it reads as expensive.

The small central pulp is very sour and very dry, and it is not the point. Candied, the albedo turns translucent and chewy with a long floral finish that a supermarket cube of green peel does not approach.

Start with the Calabrian salad, because nobody expects it. Cut away the yellow rind, discard the small sour core, and slice the white albedo thin or dice it. Dress with extra virgin olive oil, salt, oregano and chilli, and leave it half an hour. It is crisp, cool and barely bitter, and it is very good with salted anchovies or good tuna.

Candied is how the fruit travelled. Diced into panettone, cut in strips through Sicilian cassata, folded into pastiera and cannoli filling. Good candied citron is worth eating on its own with coffee.

The yellow rind, grated, is a serious aromatic and behaves differently from lemon zest: more resinous, more floral, much less acidic. Use it in pastry cream, in biscuit doughs, over baked fish, or on raw fish, where it perfumes without adding acid.

For drinks, steep the rind in neutral spirit as you would for limoncello, and the result is more bitter and more balsamic, or make cedrata, the citron cordial that was Italy's soft drink before cola arrived.

One under-used trick: slice the albedo thick, blanch it for two minutes, then sauté it in olive oil with garlic. It behaves like a vegetable rather than a fruit.

A whole fresh citron is the most patient citrus there is: that thick rind is armour, and a sound fruit keeps two to four weeks at cool room temperature in a bowl, longer in the fridge, though the cold dulls the perfume. Keep it dry and unwrapped, with air around it, and do not bag it. Once cut, the exposed pith dries and yellows within hours, so wrap the remaining half tight in the fridge and work through it in two or three days.

Over weeks the rind loses water, hardens and shrinks against the pith, the surface goes from glossy to matte and slightly wrinkled, and the aromatic oils in the peel fade, which is why the perfume is strongest in the first days. Calabrian practice is not to store the fruit at all but to convert it: candied in syrup it keeps a year in a sealed jar; the peel dries and stores in a tin; grated zest freezes in small portions for six months. Candied citron in a shop carries a date on the pack, and the maker is the reference for it.

A citron is not a big lemon. The fruit is large and heavy, often a kilo or more, with a knobbly, ribbed, thick yellow rind and oil glands you can see. Cut it and the surprise is inside: almost the whole fruit is white pith, dense and firm like a melon, with a small dry core and almost no juice. The scent is the real signature, resinous and floral rather than sharp, and it stays on your hands. The Diamante variety grown at Santa Maria is elongated rather than round.

Two things abroad borrow the name. Candied citron sold in the baking aisle is very often not citron at all but unripe melon or orange rind, dyed and sugared; read the ingredients for Citrus medica. Buddha hand is a citron too, but the fingered variety, all rind and perfume with no flesh. Fresh Calabrian citron appears in Italian greengrocers from September to November, sometimes with the Presidio Slow Food tag or Cedro di Santa Maria del Cedro on the crate, and is priced by the piece rather than the pound, commonly $8 to $15 a fruit.

Fresh citrons appear in Italian markets from October to December and in specialist grocers in the US and UK sporadically over the same months, usually at 6 to 12 dollars a pound or 8 to 16 pounds a kilo. In Calabria itself, expect 3 to 8 euro per kilo.

Candied citron is much easier to find and much more worth getting right. Italian and French pastry suppliers sell whole candied halves or large pieces at 22 to 40 euro per kilo, or 25 to 45 dollars per pound. Buy pieces rather than pre-diced cubes: you can cut them yourself and the quality is visible before you taste. Amber and translucent is right; fluorescent green or yellow, hard and rubbery is the industrial product, frequently not citron at all.

Around Sukkot, whole fruit sold as etrog is handled by religious suppliers rather than food shops, at prices unrelated to the produce market. That is a separate trade with its own standards, and the fruit is not sold for eating.

When buying fresh, pick the heaviest fruit for its size with firm, unyielding skin: weight means dense pith, which is the part you want.

Santa Maria del Cedro, in the province of Cosenza, which took its name from the fruit in 1968: the town had been called Cipollina until then. The growers' consortium is based here, along with a small museum, and it is possible to walk into a cedriera: low reed-shaded pergolas, green half-light, enormous fruit hanging at shoulder height.

Diamante, five kilometres south, is the seaside centre of the Riviera dei Cedri, its old town covered in murals, and it hosts a chilli festival in September, chilli being the coast's other obsession.

Inland the road climbs fast into the Orsomarso mountains and the edge of the Pollino: Verbicaro, Grisolia, Orsomarso, Papasidero. Twenty kilometres takes you from beach to a thousand metres.

Two different windows are worth planning around. October to December for fresh fruit, citron salad and the candying season. Late July and August for the ritual selection, when buyers work through the groves fruit by fruit, the strangest and most compelling thing on this coast.