What to Do With a Damson or Plum Glut: Jam Without a Recipe Book

If you know someone with a damson tree, you already know the problem. Late August through September, it drops more fruit than one household can eat, freeze, or give away, and most of it ends up rotting on the ground or in a bag at the back of the fridge. Plums do the same thing on a smaller scale, particularly Victorias, which crop hard in a good year and don't wait around for you to get organised.

The good news is that this particular glut is the easiest one in the kitchen calendar to deal with. Damsons and plums are naturally high in both pectin and acid, which are the two things a jam needs to set. Unlike strawberries or cherries, you don't need to buy jam sugar with added pectin, and you don't need a thermometer to get a reliable result, though one makes it easier. This is jam with the safety net left in.

Why damsons and plums are easy to preserve

Pectin is the substance in fruit that forms a gel when it's cooked with sugar and acid. Some fruit is low in it (strawberries, cherries, rhubarb) and needs help to set: jam sugar, lemon juice, or a commercial pectin. Stone fruit in the plum family sits at the other end of the scale. The skins and the stones both carry pectin, and the fruit's own acidity does the rest of the work. Damsons in particular are described by preserving guides as "exceptional" for jam because they combine both properties in one small, sharp-tasting fruit.

This matters practically because it means you can make a good batch without a special shopping trip. Ordinary granulated sugar, the fruit, and a squeeze of lemon if you want extra insurance. That's the whole ingredient list.

Where the fruit comes from

If you're growing your own, the airgap.life fruit trees course is worth working through before next winter's planting season, since a young tree bought and planted this coming winter will be cropping within two or three years and producing for decades after that. Rootstock choice, planting depth, and the first few years of formative pruning are the parts that determine whether a tree fruits reliably or sulks for a decade.

For this year, though, the fruit you need is probably already available without owning a tree. Damsons grow wild in hedgerows and old orchards across England, most famously in the Lyth and Winster valleys in Cumbria and through the old orchard counties of Herefordshire and Worcestershire, but also as stray trees at field margins almost everywhere. Picking wild fruit for personal use from a hedgerow is generally legal in England, Wales, and Scotland under the Theft Act 1968, provided you're not on private land without permission and you're not taking it to sell. Ask if you're unsure whose hedge it is, and leave plenty for the birds, who rely on the same fruit going into winter. If foraging more widely appeals, the airgap.life hedgerow foraging course covers the wider late-summer harvest, elderberries, blackberries, hazelnuts, and more, alongside the identification skills that keep it safe.

A greengrocer or farm shop is the reliable fallback. Plums are usually £2 to £3 a kilo in late August; damsons, being smaller and more fiddly to pick, tend to run a little higher, £3 to £4.50 a kilo, when a market stall has them at all. A kilo of fruit makes roughly three to four 340g jars of jam once sugar and cooking loss are accounted for.

The basic method

This isn't a strict recipe so much as a ratio, because it works whether you have 500g of fruit or five kilos.

Stone the fruit first, or don't. Damsons are notoriously fiddly to stone raw, since the flesh clings to the stone. The traditional workaround is to cook the whole fruit, stones and all, then fish the stones out with a slotted spoon once they've floated free, which happens naturally as the fruit softens. Plums are easier to halve and stone before cooking if you'd rather not deal with the floating-stone step.

Weigh the fruit and match it with sugar, roughly equal weight for weight, though many cooks reduce the sugar slightly, to around 80% of the fruit weight, since damsons and plums are already reasonably sweet-tart on their own. A splash of water, perhaps 100ml per kilo of fruit, stops the first stage catching before the fruit breaks down.

Cook the fruit gently first, without the sugar, until it's fully soft and any stones have floated to the surface and been removed. This takes 15 to 20 minutes at a simmer, depending on how ripe the fruit is. Riper fruit collapses faster.

Add the sugar, bring to a rolling boil, and cook to setting point. Setting point is 105°C on a thermometer, or the wrinkle test: put a teaspoon of the hot jam on a chilled saucer, wait a minute, and push it with a finger. If it wrinkles rather than flowing back together, it's ready. Damson and plum jam often sets a little softer than commercial jam even at the correct temperature, more of a thick spoonable set than a firm jelly, and that's normal rather than a failure.

Jar it hot, in sterilised jars, and leave it to cool undisturbed. The jam and preserves course goes through sterilising, setting point, and the full process in more detail, including what to do if a batch doesn't set the first time, which happens to everyone eventually and is almost always fixable by reboiling with a little extra lemon juice.

What can go wrong, and why it usually doesn't matter

The most common complaint with damson jam specifically is a slightly bitter edge from the skins, which some batches develop if the fruit is very underripe. Waiting until damsons have coloured fully and softened slightly before picking avoids most of this. A light frost is sometimes credited with improving flavour later in the season by converting some of the fruit's starch to sugar, though nobody should hold out for frost specifically. Ripe and softened is the test that matters, not the calendar.

The second common issue is jam that's set too firm, from overcooking past setting point. This tends to happen with a thermometer left unattended rather than a genuine timing problem, since stone fruit jam moves from "not ready" to "past ready" quite quickly once it hits a rolling boil. Testing at 103°C rather than waiting for exactly 105°C, and pulling it off the moment the wrinkle test passes, avoids most overcooked batches.

Neither problem wastes the fruit. Overset jam still tastes right, it's just firmer than shop-bought. Slightly bitter jam is still perfectly good stirred into porridge or used in a crumble filling, where a little sharpness is welcome rather than a flaw.

What to do with it once it's made

A kilo of damsons or plums, turned into jam, produces more than most households get through as toast topping alone before the next glut arrives. A few uses that go beyond the breakfast table: swirled through natural yoghurt, spooned into the centre of a Victoria sponge, warmed slightly and poured over vanilla ice cream, or used as the base of a quick pan sauce for roast pork or duck, where the acidity of the fruit does a lot of the work a red wine reduction would otherwise do.

Given away in small jars, it also solves the problem the glut created in the first place, since a friend with no damson tree of their own is usually glad to take a jar off your hands, and a homemade jar travels a lot better as a thank-you gift than most things bought at short notice.

The short version

• Damsons and plums are naturally high in pectin and acid, so no jam sugar or added pectin is needed.
• Late August to September is peak season in the UK; damsons often colour and soften into October in cooler areas.
• Foraging from hedgerows for personal use is legal in England, Wales, and Scotland under the Theft Act 1968, with permission needed on private land.
• Roughly equal weight of sugar to fruit, cooked to 105°C or the wrinkle test on a chilled saucer, sets reliably without special kit.
• Cook the fruit soft first, then remove stones as they float free, before adding sugar and boiling to setting point.
• A kilo of fruit makes three to four 340g jars, which keep for a year unopened and make an easy gift once opened jars are shared round.