Sorrento Lemon

The Limone di Sorrento is the fruit of a single cultivar, Femminello Ovale di Sorrento, protected as an IGP since 2000. Femminello is the growers' name for the group of ever-bearing lemons: trees that flower several times a year and carry blossom and fruit at the same moment.

It is a medium-large, elliptical lemon that the rules require to weigh at least 85 grams, and it usually runs between 100 and 200. The skin is deep citrine yellow, thick, and visibly pitted with oil glands. Those glands are the whole point of the designation: what is protected here is essentially aroma density in the peel.

Under the yellow sits the albedo, the white spongy layer. In an ordinary lemon it is thin and bitter and gets thrown away. In a Sorrento lemon it is thick, soft, barely bitter and faintly sweet: edible, and eaten. That is the single most useful thing to know about it.

The flesh is pale straw yellow, in eight to ten segments, juicy and with few seeds. The rules set a minimum juice yield of 25 per cent and acidity above 3.5 grams per 100 millilitres. This is not a sweet lemon; it is a sharp one with an unusually generous rind. Older growers still call it massese, after Massa Lubrense, the town with the most lemon terraces on the peninsula.

The smell arrives before the taste. Scratch the skin and the oil sprays out: floral, resinous, closer to neroli and bergamot than to the flat citrus-cleaner note of a supermarket lemon, and it stays on your fingers for half an hour.

The juice is properly sour, with more body than a Eureka lemon and none of the sweetness of a Meyer. It is bright rather than harsh, and it carries a faintly bitter-almond finish.

The pith is the surprise. Bite a slice cut across the whole fruit and the white layer is cool, spongy and mildly sweet, closer to firm melon rind than to anything you associate with lemon peel.

Start with the peel, because that is where the value is. Zest with a microplane, taking only the yellow, and add it off the heat: essential oils start disappearing with the steam above about 70°C, so zest stirred into a hot pan at the end delivers far more than zest cooked from the start.

Spaghetti al limone is the simplest demonstration: zest, good olive oil, black pepper, a ladle of pasta water and grated cheese, emulsified off the flame. No juice at all, or barely a spoonful.

For limoncello, peel the fruit with a vegetable peeler and leave the white behind, because pith in the alcohol makes the liqueur bitter. Steep the peels in high-proof neutral alcohol for seven to ten days, strain, then dilute with a cooled sugar syrup. A common home ratio is 1 kg of fresh peel to 1 litre of alcohol, extended with about 1.5 litres of syrup. Serve it at minus five, not at room temperature.

The lemon salad needs the real fruit: remove only the yellow skin, slice across at half a centimetre so each round is mostly white pith, dress with olive oil, salt, garlic, chilli and mint, and leave it half an hour.

And the obvious things, done properly: whole slices under and over a baked fish, candied peel, and granita of nothing but juice and sugar.

At room temperature, in an open basket away from sunlight, they hold a good week, softening gradually as they lose water through the skin. In the fridge, in the vegetable drawer and not sealed inside a plastic bag, three weeks is straightforward. A closed bag traps condensation against the peel, and surface moulds appear faster there.

Do not wash them before storing, for the same reason. Over the weeks the skin dries and tightens and the fruit gives up less juice, while the peel keeps its oil, which is why older Sorrento lemons end up in limoncello rather than in a glass.

Zest freezes, and it is the best way to waste nothing: grated and spread flat in a container, or in whole strips in a bag, it holds around six months before the aroma thins. Juice freezes too, in ice cube trays, at roughly 15 millilitres a cube. One practical note: these are unwaxed fruit, so brown flecks and rough patches on the skin are simply what untreated citrus looks like.

Shape comes first: elliptical and elongated rather than round, with a barely marked tip. The skin is deep yellow and rough under the fingers, and the oil pores are visible without looking hard. Scratch the peel with a nail and the essential oil sprays out, and the scent stays on your fingers for half an hour.

Weight is the simplest test. A Limone di Sorrento IGP weighs at least 85 grams and usually between 100 and 200, noticeably heavier than a standard supermarket lemon. Cut across, the peel is several millimetres thick and the white pith under it is thick, firm and dry: taste a piece, and on the right fruit it reads faintly sweet rather than bitter. The pack, or the sticker on the individual fruit, should show the European IGP logo, the words Limone di Sorrento and the consortium.

The usual substitutions abroad are Siracusa IGP lemons, excellent but smaller and thin skinned; plain Italian lemons grown on flat land, similar in shape but low in oil; and Sfusato Amalfitano, a separate IGP, tapered with a pronounced point.

Fresh Italian lemons are harder to find abroad than the marketing suggests. In the United States, phytosanitary rules keep most Italian citrus out of general retail; what arrives comes through specialist importers in short seasonal runs, and the dependable Sorrento products on US shelves are limoncello and candied peel rather than fruit. If fresh ones turn up between April and July, expect roughly 10 to 18 dollars a pound.

The UK is easier: Italian citrus reaches London greengrocers and specialists such as Natoora in season, and Italian delicatessens bring in Amalfi and Sorrento lemons from spring into summer. Budget 12 to 20 pounds a kilo. In Italy the same fruit is 2.50 to 4 euros a kilo on the peninsula and 6 to 10 elsewhere.

What to check: elliptical shape, at least 85 grams, visibly pitted skin, and no wax sheen. Genuine IGP fruit is untreated after harvest, so slightly rough or blotchy skin is normal and a mirror finish is a warning sign. Look for the EU IGP mark on the crate or the sticker.

And check the calendar. The IGP harvest runs February to October. A lemon sold as Sorrento in December came from somewhere else.

Massa Lubrense is the place to start: it has more lemon terraces than any other town on the peninsula, and several farms open their groves to visitors. Walking under a pagliarella, the chestnut-pole canopy that covers the whole plot, explains the price of the fruit faster than any label.

Sorrento itself is worth it if you get past the souvenir limoncello: the town's pastry shops make delizia al limone, best eaten cold and on the day. Sant'Agnello and Piano di Sorrento are quieter and more agricultural, with growers selling from roadside stands, and Vico Equense at the northern end pairs the lemons with the oily local fish.

Sant'Agata sui Due Golfi, on the ridge above Massa Lubrense with a view over both bays, is where the region's serious kitchens made the case for lemon in savoury cooking rather than only in dessert. Capri falls inside the IGP zone too, and terraced groves survive above Marina Grande.

Come in May or June. Flowering and harvest overlap, the groves smell of zagara, the orange-blossom scent of the citrus flowers, and the fruit is at its most aromatic.