Walnuts are one of the most popular nuts for snacking and baking alike, always great to have on hand in the kitchen. These versatile nuts are good eaten raw or roasted, in either sweet or savoury dishes and offer a significant amount of health benefits.
Many people assume they are an exotic crop coming exclusively from somewhere in California. Although is not too common to find a wild walnut tree growing in Britain, you certainly can, as squirrels inadvertently plant them in unlikely places. Otherwise, they are most likely to be found in public parks.
Description and species
English walnut (Juglans regia), also known as Persian walnut, is a deciduous tree native to Central Asia and Southern Europe, now widely naturalised in Europe. Actually, it’s not native to England, but it has been cultivated here for 500 years for its nuts and wood.
This large deciduous tree with distinctly furrowed bark grow up to 30m high and display alternate glossy leaves of five to nine leaflets with prominent midribs and veins. They are slightly pointed with smooth edges and are highly aromatic when crushed.
Male flowers appear on new growth, while female clusters appear on old wood in early Spring. Nuts develop in a pitted shell surrounded by a green leathery outer husk which splits when they ripen in Autumn.
Notes on edibility
Fresh walnuts are quite damp and have a mild milky flavour, which explains why they are called “wet walnuts”. The flavour has not yet developed completely like the shop-bought ones we are familiarised with, because they need to be cured and dried first.
Green walnuts are also consumed unripe, when the green fruit has not yet developed the nut inside. It can create a very unique condiment with a rich dark colour and a singular taste.
Walnuts are rich in antioxidants and are a natural source of manganese, which maintains healthy cells and strong bones, keeps blood sugar levels normal and even reduce heart disease. They are also rich in oils, omega-3 and fatty acids.
People who are allergic to nuts should still stay away from wild walnuts.
Foraging in season
Despite the name, English walnut is not a native species to Britain, however it’s widely planted in parks, sometimes inadvertently done by squirrels. It can be found around cultivated areas and grow in sheltered hedgerows, as long as it receives full sun.
Walnuts are usually harvested when fully ripe and dry in early Autumn, as soon as the husks start to split. You know they are ready when you start to notice a pile of discarded nut cases on the ground. Just shake low branches and pick up the fallen husks and bare shells to sort at home.
In cooler areas, walnuts may not fully ripen. However, unripe green hulls can be picked in early summer to pickle, use as a condiment or infuse in alcohol.
Walnut trees can take up to 15 years of age to start fruiting, so it’s not always the case you are guaranteed with nuts on season after you find a tree; they reach the most productivity at the age of 30. However a good old mature tree can produce about 50 kg of nuts per season, so it’s well worth the wait!
Storage and processing
I’ll give you a word of caution before you touch any fresh walnuts: always wear gloves. The husks turn everything yellow (which becomes black afterwards) and the stain will hang around for days and even weeks. It will eventually go off but in the meantime you will look like a garage mechanic.
Once you are armed with a pair of gloves, remove the husks first. Just pull them off to reveal the walnut shells. Some of them you will notice are black because they are starting to rot; don’t worry, they are fine to pick, as it does not spoil the nut inside.
Walnuts in their shells can be opened using a nut cracker, gently squeezing the shell until it cracks. Shelling takes a bit of patience and you will struggle to get a single whole nut at the beginning; though you will quickly get the gist.
Fresh walnuts are fine to eat as they are, but the flavour has not yet developed completely and will not keep well because the kernel inside is damp. You need to cure them first and dry the walnuts for at least two weeks, laying them on a rack somewhere warm.
The challenge seems to be getting them dried without mould; leave them in a place with poor ventilation and your harvest will be spoiled soon. A mould infested batch should be discarded, as it produces aflatoxin, which is a powerful carcinogen.
Once completely dry and kept in the shell in a cool dark place, walnuts will last for months. Shelled nuts are exposed to oxygen, which will cause them to turn rancid since they are naturally rich in fats. However, they keep well in the fridge (and even in the freezer) for long.
Lastly, another warning: don’t put any parts of the walnut in the compost heap or in your garden, as the plant contain juglones, an allelopathic chemical that inhibits the growth of other plants nearby, eventually killing them.
Culinary uses and recipes
Walnuts are creamy, nutty and mildly bitter in taste and are good eaten as they are or toasted to bring out more of their flavour. These nuts are one of the most popular and versatile, as they can be used in either sweet or savoury dishes.
Best combinations pair walnuts with blue/goat cheese, yoghourt, honey, pears or dried figs. Winter salads often feature walnuts, as it’s the case of Waldorf salad, which combines them with apple and celery. On the other hand, flavoursome pasta dishes successfully combine blue cheese and walnuts.
In fact, there are plenty of sauces that can be enriched with walnuts. Muhammara is a Middle Eastern dip made of peppers, ground walnuts and breadcrumbs. Walnut sauces are prominently featured in Georgian cuisine; for instance, Satsivi is a walnut paste similar to tahini, most commonly added to turkey as a staple of winter holiday feasts.
There is a Victorian recipe calling for ‘walnut ketchup’, which is fairly similar to Worcester sauce; it’s a mixture made with green walnuts, vinegar, anchovies and spices that takes at least 1 year to mature. Alternatively, pickled green walnuts can be eaten with cold meat and cheese.
Walnuts are also a very popular snack, either raw, toasted, candied or covered in chocolate. Every Christmas, my father would show me how to make ‘turron de pobre’ (poor man’s nougat): it was just a walnut-stuffed dried fig, which in fact it’s tastier (and healthier) than genuine nougat.
Nut bars, granola, muesli and biscuits recipes benefit of some walnuts thrown in and they are particularly useful for baking. Think of banana & walnut bread, carrot cake, baklava, coffe & walnut cake or torta nera (walnut chocolate tart)
Awesome booze can be made infusing green walnuts in alcohol; vin de noix is a French aperitif made of red wine, eau de vie and green walnut whereas nocino is a bittersweet and aromatic Italian digestivo made of eau de vie, green walnut and spices.
The sky is the limit! Have you got any other interesting recipe to share?