When to Harvest Hazelnuts: Husk Color, Drying and Storage

Read the husk, not the shell

The nut is hidden inside a leafy husk, so you cannot see the shell color from the outside. What you judge instead is the husk. All summer it is soft, bright green and gripping the nut tightly. As the nut fills, the husk loses its shine, the edges begin to brown and dry, and the whole thing shades to a pale straw yellow. That color change is the signal, and it typically arrives in late summer to early autumn, four to five months after the tiny red flowers were pollinated in midwinter.

Confirm with a thumb test. Pick a nut, hold the husk and push the nut with your thumb. A ripe nut slides out of the husk cleanly and the shell underneath is a hard, glossy tan rather than white or blotchy green. If the nut is welded into the husk and tears the husk apart on the way out, come back in a week. Nuts pulled at that stage have soft, rubbery kernels that shrink to nothing when dried.

The second signal is drop. Ripe nuts release themselves, either bare or still in the husk, and you will find them under the bush after wind. Once a few are dropping naturally the whole bush is within about ten days of being ready. On a mature bush the crop does not ripen all at once, so expect to go over it two or three times about a week apart rather than stripping it in one afternoon.

Pick early rather than late

This is the one crop where the textbook advice to wait for perfect ripeness will lose you everything. Squirrels start on hazelnuts while the shells are still pale, and they work a bush from the top down in a matter of days. If you plan to harvest at full husk yellow, you are competing against an animal that is happy to take the crop a week or two earlier and does not mind the slightly under-filled kernels.

The practical answer is to pick as soon as the shells have hardened to a solid tan and the husks are just starting to turn, even if a third of the husks are still green. Nuts at that stage finish ripening off the bush if you dry them slowly in their husks. You lose a little size and a little flavor. You lose the entire crop if you wait and the squirrels arrive first.

Gather everything under the bush at each pass as well. Nuts lying on damp ground pick up mold spores within days, and a single moldy nut in a storage jar taints the batch around it. Anything with a hole bored neatly through the shell is weevil-damaged and goes in the bin, not the compost.

Test-crack five nuts from each pass before you commit to picking the bush. A shriveled kernel rattling in a full-sized shell means the nut was never pollinated properly, and no amount of extra waiting will fill it.

Drying, the step people skip

A freshly picked hazelnut is about twenty percent moisture. It will not keep at that level; within a few weeks the kernels go rancid or grow mold inside an apparently sound shell. Drying takes them down to roughly five to eight percent, at which point they are stable for the best part of a year. This is the difference between a jar you enjoy all winter and a jar you throw away in early autumn.

Dry them slowly and in air, not in an oven. Spread the nuts one layer deep on trays or slatted racks in a dry, airy, shaded place: a shed, a covered porch, an unheated spare room. Anywhere between 60F and 75F (16C to 24C) with moving air is right. Direct sun cooks the oils and gives a stale taste, and a hot oven does the same thing faster. Turn them by hand every few days so the undersides dry evenly.

Two to three weeks is normal for husked nuts, three to four for nuts still in their husks. Test rather than count days: the kernel should snap cleanly rather than bend, the shell should sound hollow when two nuts are knocked together, and the papery skin should rub off a cracked kernel readily. If the kernel is leathery, keep going.

1. Strip the husks Rub the dry husks off by hand or in a coarse sack. Green husks that will not come away mean the nut is under-ripe, so set those aside and dry them in the husk for another week or two before trying again.
2. Float test the batch Tip the nuts into a bucket of water. Floaters are empty, weevil-hollowed or shriveled, so scoop them off and discard them. Sinkers are the crop. Drain and pat them dry immediately, then get them onto the drying racks the same day.
3. Dry in a single layer One nut deep on trays in a shaded, airy place at 60-75F (16-24C). Turn every three days. Do not pile them; the center of a heap stays damp and molds while the outside dries.
4. Test before storing Crack five nuts from different trays. Kernels should snap, not bend, and the brown skin should flake off easily. If any kernel is soft, give the whole batch another five days rather than storing a mixed batch.
5. Store cool and airtight In shell, in a sealed jar or tin in a cool dark cupboard, they keep eight to twelve months. Shelled kernels have far less shelf life: about three months in a cupboard, six in the fridge, a year or more in the freezer.

What to write down this season

Record the date you saw the first husk turn yellow and the date of the first natural drop on each bush. Those two dates repeat within about a week from one year to the next, and once you have two seasons of them you know exactly when to have the netting up and the traps out rather than guessing.

Also note the weight or count from each bush, which bush produced it, and the proportion of floaters in the water test. A bush with a good crop of full nuts is pollinating well. A bush with plenty of shells but a high floater rate has a pollination problem, not a feeding problem, and the fix is a different partner bush rather than more fertilizer.

Finally, log the date you took the nuts off the drying rack and the date you first opened the jar. If the nuts were soft or musty when you came to eat them, the drying was short, and next year you extend it by a week rather than repeating the same mistake.