Sweet chestnuts drop through October and into November once the spiny cases split open on the tree. They're best collected from the ground within a day or two, before slugs and wet grass get to them. Picked straight off the tree the nuts are starchy and bland; a few weeks curing in a cool, airy spot converts some of that starch to sugar, which is what actually gives a roast chestnut its flavour. This is the husking, sorting and curing done properly, not just the picking up.

Harvest, Husk and Cure Sweet Chestnuts for Winter Storage

What you need

1 pair thick gardening gloves leather or heavy rubber-coated, not thin fabric ones
1 trug or bucket for collecting husks from the ground
1 large bowl of water for the float test
2 shallow trays for curing in a single layer
1 hessian sack or perforated bag for storing cured nuts

Step by step

Collect fallen husks from the ground, wearing gloves throughout. Leave any still tightly closed on the tree for another day or two.
20 min
Crack each husk open by treading on it firmly with a boot sole, or splitting it with secateurs, then pick the nuts out with gloved fingers.
40 min
Drop the husked nuts into a bowl of water. Discard anything that floats — it's usually hollow or insect-damaged inside. Keep only the ones that sink.
10 min
Spread the sound nuts in a single layer on trays, somewhere cool, dark and airy — a shed or unheated porch, not the kitchen. Turn them once a day.
10 min
Check the trays daily for the first week. Pull out and bin any nut that softens, shrivels or shows mould before it touches the rest.
10 min
Cure for one to three weeks until the shells feel slightly leathery rather than rock hard, then move the nuts to a hessian sack or perforated bag.

Afterwards

Rinse the bowl and trays, since any husk dust left to sit can mark wood. Check the stored bag weekly — chestnuts don't keep as long as most tree nuts, so eat or cook within a few weeks, or shell and freeze a batch for longer storage once cured.

Questions

Can I eat them straight off the tree without curing?

You can, but they'll taste starchy and faintly bitter. Curing for one to three weeks is what develops the sweetness.

Most of my nuts floated — is that normal?

In a poor year it's common for a third or more to be hollow or carrying a grub. The float test catches them before they spoil the rest in storage.

How long do cured chestnuts actually keep?

A few weeks in a cool place, a bit longer in the fridge in a perforated bag. For months, shell them after curing and freeze.

Do I need to cut a cross in the shell before storing?

No — that's only needed just before roasting or boiling, to stop them bursting in the heat. Leave shells whole in storage.