Introduction
There is evidence that hazelnuts have been eaten in Britain since the stone age (Mesolithic), before the adoption of farming, and for good reason. They taste delicious, particularly when roasted and they also store well. Getting the best out of foraged or home grown hazelnuts isn't difficult but, if like me, you grew up in a city you probably never learnt how to do it. I've been growing hazelnuts in my small forest garden for about eight years and they are one of the most productive crops in the garden. So much so that I've had to learn how to store and prepare them.
When to pick
The standard advice about when to pick is when the husks are turning brown in September/October. When I look back at my records I tend to pick a bit earlier in late August/early September when the husks are starting to brown. The nuts on some of the trees develop earlier than others which I think depends on their position and how much sun they get rather than the variety (I have a Nottingham Cobnut, Kentish Cob, Red Filbert and a semi-ornamental twisted hazel). I err on the early side as I do not yet have any squirrels that visit the garden. I'm keen to keep it that way and I've discovered that the nuts continue to ripen off the tree if you have somewhere to air dry them. The same applies to foraging if you want to get there before they are all gone.
The first set of images below show some very green and unripe nuts. I would not normally pick them this early but they will continue to dry and darken if you do have some at this stage. These were taken on the day of picking.
The first set of images below show some very green and unripe nuts. I would not normally pick them this early but they will continue to dry and darken if you do have some at this stage. These were taken on the day of picking.
The pictures below show clusters of nuts picked when riper (17-18 Aug 2017) that have been dried for about ten days (photographed 27 Aug 2017). The first four are from the Nottingham Cobnut or Kentish Cob (actually these are both filberts apparently) while the last three are from the Red Filbert. The first four were not as brown when picked. You can see that the nuts come out very easily on these. Just handling them when laying them out for drying is enough for some to pop out. The shape of the nuts from the Red Filbert is much more rounded. It reminds me of the kind of shop bought hazelnuts we would get at Christmas time.
Drying
I dry the nuts after picking. This is particularly important if you are harvesting them a little early. Picking in dry weather helps but isn't always possible. Even if the nuts are dry to the touch they benefit from extended drying over a period of at least several weeks. The water content of the nut reduces as does the kernel inside. I believe there are also chemical changes to the kernel that probably depend on the temperature and extent of drying. In my experience the nuts taste much better once dried for a couple of months or more. The flavour is much improved by roasting too (see below). Reducing the water content is also really important if you intend to store them for longer.
I have tried a few ways to dry the freshly picked hazelnuts. I tend to dry them while still in their husks purely because of the time taken to de-husk them. However, it is probably easier to de-husk them before they dry too far. Removing the husks probably helps the nuts to dry more quickly. I now use a collapsible mesh drying rack that packs away when not in use. I spread the nuts out on the four layers and put in a cool garage in the dark. The space has plenty of ventilation to remove the moisture. In the paste I've slung them between two poles covered with mesh. That worked fine but was a little slower and the nuts needed turning every so often. Wherever you put them make sure they are away from mice and squirrels.
I have tried a few ways to dry the freshly picked hazelnuts. I tend to dry them while still in their husks purely because of the time taken to de-husk them. However, it is probably easier to de-husk them before they dry too far. Removing the husks probably helps the nuts to dry more quickly. I now use a collapsible mesh drying rack that packs away when not in use. I spread the nuts out on the four layers and put in a cool garage in the dark. The space has plenty of ventilation to remove the moisture. In the paste I've slung them between two poles covered with mesh. That worked fine but was a little slower and the nuts needed turning every so often. Wherever you put them make sure they are away from mice and squirrels.
Storage
Once the nuts have been dried for a while they are pretty good to eat. On the other hand, I have tried eating them when fresh and also roasting them when fresh. They taste quite different and don't roast well at all (at least I haven't figured out how to do it successfully). The kernel tends to fall apart when fresh when split but once dried it holds its shape much better and is clearly different when compared. The picture below show some fresh and dried nuts. The first four pictures show a nut that was only dried for 10 days. The next three show one that had been stored from last year. The last one shows a fresh nut on the left and a dried one on the right.
Even when the nuts are visibly dry and good to eat and roast they are likely to continue to dry over time. Once they are separated from their husks they can be put into storage jars. However, I have found that putting them into a closed jar can lead to them developing mould on the outside of the shells after some time. They will be fine for a little while but not for months and months. To further dry the nuts I have had some luck with vacuum jars. These are rigid plastic jars that let you suck the air (and moisture) out. I keep the unshelled nuts in those for several months (checking the vacuum every so often). I've also put them into glass jars and left an air gap or used some paper kitchen towel to allow any moisture to escape.
Roasting
I don't think I've got the details just right but having shelled the nuts I roast them at about 180oC on a baking tray. I check them after 10-15 min. In the past I have removed the skins by rubbing them in a damp tea towel once out of the oven. However, apparently the skins are www.ncbi.nlm.nih.gov/pubmed/21535710really good for you so I'm going to leave them on next time.
More resources
I've found that there is lots of different advice out there. Not all of it worked for me but I found some of it useful:
Harvesting, Handling, and Storing Nuts from the Home Orchard -extension.oregonstate.edu/fch/sites/default/files/documents/fs_146_harvestinghandlingstoringnuts.pdf
How to Grow Hazelnuts – A Guide to Growing Hazelnuts
www.allotment-garden.org/nuts/hazelnuts-growing/
Roasting affects phenolic composition and antioxidative activity of hazelnuts (Corylus avellana L.)
www.ncbi.nlm.nih.gov/pubmed/21535710
Harvesting, Handling, and Storing Nuts from the Home Orchard -extension.oregonstate.edu/fch/sites/default/files/documents/fs_146_harvestinghandlingstoringnuts.pdf
How to Grow Hazelnuts – A Guide to Growing Hazelnuts
www.allotment-garden.org/nuts/hazelnuts-growing/
Roasting affects phenolic composition and antioxidative activity of hazelnuts (Corylus avellana L.)
www.ncbi.nlm.nih.gov/pubmed/21535710