Why sloes are worth the wait

Sloes are the fruit of the blackthorn, that thorny, unglamorous shrub lining so many of our hedgerows. Eaten straight from the bush in September they are a disappointment: hard, mouth-puckering and fiercely astringent, with a tannin kick that dries the tongue.

Give them a few more weeks and they become something else entirely. The old rule is to wait until after the first frosts, and it is a good one. Freezing breaks down the cell walls, so the juice gives itself up more readily and the flavour rounds out into something deeper and more plummy. Strictly speaking, frost does not make a sloe sweeter — nothing does, this late in the year — but it certainly makes a finer cordial.

In a mild autumn the first proper frost may not arrive until November or even December. Do not let that stop you. Pick when the sloes are fully coloured and yielding, then give them a night in the freezer to do the same job.

Finding and identifying blackthorn

Blackthorn is easiest to spot in early spring, when it flowers on bare wood: clouds of small, five-petalled white blossom along the hedge, well before the leaves appear. By autumn you have to look harder. The bark is dark and twiggy, and the stems carry long, sharp spines. Any remaining leaves are small, oval and finely toothed.

The fruit is round, roughly a centimetre across, deep blue-black with a soft powdery bloom, like a tiny, dull damson. It hangs singly or in twos and threes, often tucked among the spines where it is awkward to reach — nature's way of protecting the crop, and your fingers.

Do be careful with lookalikes. Bullaces and wild damsons are close relatives and perfectly good to eat, just larger and sweeter. The berries of purging buckthorn are darker and rounder and best left well alone, though that plant has no spines. If you are not certain, check a good field guide and come back next week. Never eat a wild fruit you cannot identify with total confidence.

Picking well: timing, kit and courtesy

• Timing: late October through November, after the first frosts where possible. Choose fully coloured, slightly soft fruit; hard green sloes make a thin, bitter cordial.
• Kit: gardening gloves, an old coat, a bucket or strong bag, and a hooked stick for pulling high branches within reach.
• Where: hedgerows, field edges, scrub and rough common land. Avoid busy roadside verges, which gather dust and may be sprayed, and never pick on private land without asking.
• How much: take no more than a third of the fruit from any one bush. Leave the rest for the fieldfares, redwings and thrushes that arrive for the winter berry crop.

In England and Wales, picking wild fruit, foliage and fungi for personal use is permitted under the Theft Act 1968, provided you are not doing it for profit and are not trespassing — but uprooting a plant needs the landowner's permission. It is always worth knocking on a farmhouse door and asking.

The cordial itself: sugar, spirit and time

Most kitchens know this drink as sloe gin, and that is exactly what it is, though the word cordial does it more justice: sweet, dark and syrupy, made to be sipped slowly or lengthened with something fizzy.

For a first batch you will need:

• 600g sloes
• 300g caster or granulated sugar, up to 400g if you like it sweet
• 1 litre gin — a plain London dry works well, though vodka gives a cleaner fruit flavour
• A large sterilised jar or two, a clean needle or a freezer, and a square of muslin

Prick each sloe two or three times with the needle, or simply freeze them overnight and let the cold do the work. Tip them into the jar, pour over the sugar and then the gin, seal, and shake gently to start the sugar dissolving.

Steeping, shaking and straining

Keep the jar somewhere cool and dark, and shake it every few days for the first fortnight, then once a week after that. The sugar will dissolve, the fruit will fade to a pale, spent grey, and the liquid will turn a deep ruby.

Leave it for at least three months; longer is better. Line a sieve or funnel with muslin and strain the cordial into a clean jug, letting it drip through in its own time. Squeezing the muslin hard will cloud the drink with fine sediment. Decant into sterilised bottles, label with the date, and store in a dark cupboard.

It will keep for two or three years, and improves for the first twelve months as the flavours settle. Taste it at three months and you will understand what all the patience was for.

Drinking it, and a few other uses

Serve it neat and cold in a small glass, or over ice with a splash of tonic, lemonade or soda. It is very good in a hip flask on a frosty walk, and even better poured over vanilla ice cream or a baked apple. A spoonful stirred into a glass of sparkling wine makes a fine winter aperitif.

If you would rather avoid alcohol, simmer equal weights of sloes and sugar with water to cover for about twenty minutes, mash, strain and bottle. That gives a tart, fruity cordial, excellent with soda water, which keeps a fortnight in the fridge or freezes well in small bottles.

Either way, the real pleasure is in the making — an hour or two in a hedgerow in late autumn, cold hands, purple fingers, and a shelf of dark bottles to see you through to spring.