2025 has been a mast year for most fruit and nuts and delivered the best crop of walnuts that I have had in the 24 years since moving to a house with a walnut tree. There was so much else for squirrels to eat that for once they left our walnuts alone and we even had a surplus to sell.
Almost 40% of the worldwide export in walnuts comes from California, with the UK being their 5th largest market. Walnuts are a rich plant source of Omega 3, and so of special importance in vegan and vegetarian diets, although valued by all for their health-giving antioxidants. The UK market looks likely to continue to expand whilst repeated drought and wildfires in California throws into question walnut production there. However, Californian walnuts are sold in supermarkets for less than half the price of the rarely found home produced walnut.
Californian walnuts are what I had eaten for most of my life until a friend brought a sack back from France. These walnuts were from Grenoble, the first fruit to receive the French quality symbol that went on to become known as “Protected Designation of Origen”. Périgord was later also awarded PDO status and is probably the better-known region for French walnuts. The ones my friend had brought home from Grenoble were a complete revelation to me. Finally, I understood the fuss about walnuts and from then on Californian just wouldn’t do.
The following year I saw “wet walnuts” for sale in Somerset and, despite their unappetising appearance, leapt to buy them. Walnuts are “wet” when they first ripen in September and you could literally squeeze oil from them by hand. The shells are blacker at this stage, so they don’t look particularly appetising. When you crack them open the skin is still soft enough that you can peel it away and, as the skin is the most bitter part, you may well wish to do this. Wet walnuts are ideal for pounding to make a sauce – for example to serve with pasta or fish. However, the nuts won’t store for long unless you dry them. Walnut oil is very unstable, so even when dried they are best eaten within a few months and once shelled should be eaten immediately. The freshness is probably what made my first taste of Grenoble walnuts so wonderful, and I am now firmly wedded to the seasonal aspect of the nut. If I see them listed amongst the ingredients of an otherwise clearly summer dish it really jars with me, so whilst some people might see them as a year-round provider of essential nutrients, for me they shout Autumn and Winter.
In addition to the over-riding importance of freshness, the question of the suitability of the trees to a particular area definitely intrigues me. I accept that the regions of Périgord and Grenoble in France are ideally suited to growing walnuts, but what I can’t say, at this time, is whether we have similarly suitable areas in the UK.
Walnut trees are slow growing but long lived. They require plenty of space and the land beneath becomes fairly barren owing to the chemical juglone produced by the roots, so it is often planted on the periphery in agroforestry. It takes 10 years for a tree to start producing a decent number of nuts, and even then, nut production is fairly hit and miss. No-one seems to be quite able to explain why some trees do well and others do not. There is an old rhyme that hints at this problem although containing no sensible advice:
A woman, a dog and a walnut tree,
The more you beat them the better they be.
Certainly, walnut trees are unlikely to produce nuts consistently in the northern part of this country and locally in Somerset I have found them to be more forthcoming on the warmer southern flank of the Mendips than on the north, although even here I know ancient trees producing well and others that do not.
In the late 15th century Surrey was at the heart of walnut growing in the UK. This came about when John Evelyn was asked by the Royal Society to draw attention to the damage done to England’s wooded estates during the English Interregnum and to encourage reforestation. His findings were published in 1664 under the title “Sylva or a discourse on forest trees and the propagation of timber in His Majesty’s dominions”. He championed the growth of walnut plantations on several family estates, including his own around Godstone, and elsewhere in Surrey, notably at Leatherhead and Carshalton. The walnut tree was clearly suited to the Surrey soil, although whether it was especially so or just the result of many large estates being found in proximity to the court is not certain. Whilst some people are lucky enough to have their own walnut tree, because of the space required they have always been more associated with large properties. Their prestigious status is evident from the number of times their presence at a property, even as a single tree, is reflected in the house name.
However, Evelyn’s project came to an abrupt end just two years after his death, when the bitter winter of 1708 destroyed most walnut trees in northern Europe. Trees were replanted, but commercially it became their timber that produced the greatest value. Walnut wood is used in cabinet making, marquetry and for gun stocks. Many trees were felled for this latter purpose for the Napoleonic Wars in the 19th century. The same thing happened again in the Crimean War to the extent that one Birmingham arms maker had to transfer his operations to Turin where the supply of walnut wood was more assured.
And so, we find the current position in Britain today is that walnut trees are mainly grown in isolation if the garden is large enough or the remnants of large estate plantings might be found around its margins. Bossington, part of the Holnicote estate on Exmoor, provides a great example of the latter. You can find seven walnuts trees of varying ages around the green and more along nearby roadsides. The once famous giant tree which had dwarfed a cottage beside the green was felled in the 1950s.
A more recent estate planting exists near Glastonbury. Roger Saul decided to replant walnut trees at Sharpham Park when he discovered evidence of them having been grown there when it was a monastery. 300 trees were planted in 2004 and 12 years later they were producing enough nuts to sell. British walnuts (and Sharpham Park’s are Organic) sell for more than £20 a kilo. You can also buy British walnuts, along with Kentish Cobnuts, online from Potash Farm in Kent.
As yet, few people seem to appreciate the qualities of British walnuts sufficiently to create much demand, although I am convinced that when they taste them they will never look back. The most widely planted variety of walnut tree in the UK is Broadview, but there are many modern hybrids available to suit specific requirements – see www.walnuttrees.co.uk .
Pickled Walnuts
Planting is a long-term investment as it can take decades to see a decent crop of nuts. Squirrels may get to your crop before they fall, and in an effort to beat them to it, I have harvested some of our nuts when “green”, in early July, and pickled them. Pickled Walnuts are the only culinary use for walnuts for which the British have gained any renown, although we are not by any stretch, the only culture to use this method to preserve them. One researcher identified more than 60 distinct recipes for pickled walnuts from countries as diverse as Australia, Britain, Canada, China, France, Germany, Greece, Holland, India, Italy, Mexico, New Zealand, Portugal, Russia and Ukraine. Two features stood out that distinguish “British Pickled Walnuts” (those originating in British speaking countries): – none of them include garlic and all of them include sugar of some type. About half of the British recipes include ginger.
The inclusion of a sweetener affects the preserving process and necessitates heat processing in a water bath. This process also softens the nuts, some feel before the spices have fully penetrated. I decided to test two recipes, one from the WI, including sweetener and heat processing, the other from Hugh Fearnley-Whittingstall, which does not include sweetener and therefore no heat processing. The WI version is by far my favourite being edible by the Christmas after making. I have tasted the Hugh Fearnley-Whittingstall version on subsequent years but still find them overly harsh.
The use of pickled walnuts is as variable as the recipes, but here in Britain they are almost exclusively used as an accompaniment for cold or grilled meats. I have also given Dr Kitchener’s recipe for “Wow-Wow Sauce” which dates back to 1817 as an example of the particularly British use of pickled walnuts.
Drying walnuts in their shell
Once you have sufficient crop for storing, drying becomes the issue. Walnuts are gathered from the ground rather than picked from the tree and unless a particularly strong wind brings them all down, they may continue falling over a period of a couple of weeks. The green casing enclosing the nut should have broken, or at least be easily dislodged with your boot, as the nuts will not dry properly if part of the case remains. Wear gloves when you collect the walnuts or they will stain your fingers dreadfully.
If the weather is dry and ideally with sun but a bit of a breeze, they will dry well outdoors. I spread them out on a large rack, but smaller racks can also be handy for bringing in quickly overnight or if it rains. Turn the nuts regularly so that they dry evenly. Usually, I can achieve only some of the drying this way and then have to continue it indoors.
The ideal indoor conditions would be a dry, warm (27-31˚C) room with good air circulation. A friend had just such a room, which contained a woodburning stove, and he suspended the walnuts in a hammock. My house is not so warm, but we do now have a room dehumidifier which helps. Dependent on the conditions it will take around 10 days to dry the nuts sufficiently that they will store without going mouldy. If you over dry them, or use too much heat, the nut will shrink and become brittle so that it is difficult to extract a whole nut cleanly. Although it is possible to dry the nuts shelled, remember that once they don’t have the protection of the shell their lifespan is very significantly shortened – they will taste stale and musty within days.
Finally, I roll the dried nuts in a cloth bag to remove as much dry debris as possible to leave a reasonably clean looking shell. I then store them in string bags to aid circulation but in a cooler room.
That’s another essential element of the Christmas table home produced!
Further Reading
A Passion for Trees: The Legacy of John Evelyn, by Maggie Campbell-Culver 2006
https://www.permaculture.co.uk/articles/why-you-should-grow-walnuts-juglans-regia includes a link to companion crops that seem unaffected by juglone.
Parts of this article were originally published on The Campaign for Real Farming website in September 2020.
How to Pickle Walnuts
Pick Green Walnuts between mid-June and mid-July (21st at the very latest) before the shell has begun to form around the inner kernel. You can test for this by passing a thick needle or skewer right through the walnut. Wear gloves when doing this as the clear juices exuded by the walnut will dye anything they come into contact with a very dark brown.
Step 1 – Brining
This is necessary to draw out the toxins. Make a brine at the strength of 150g salt for each litre of water. You need sufficient water to completely cover the walnuts. Prick the walnuts in several places to help them eliminate the toxins. Over the next few days the water will turn dark – it is a good idea to drain this off and replace with fresh brine every three days. It will take 9 days to draw out all of the toxins.
Step 2 – Drying
Rinse in fresh water and then leave to dry on a rack, in the sunshine if possible. The walnuts should not be touching and should be turned occasionally. After two to three days (depending on the drying conditions) the walnuts will turn black and you are then ready to proceed to the next stage.
Step 3 – Making the pickling vinegar
Having experimented with different cures I prefer the sweet cure recommended by the WI, although have substituted cider vinegar for their malt vinegar.
1 litre cider vinegar
500 g dark brown sugar
Teaspoon each of salt, black peppercorns, allspice berries, cloves
1 stick cinnamon
1 tbsp peeled and grated fresh ginger
Heat the vinegar and flavouring ingredients for 15 minutes then leave until cold before bottling.
Step 4 – Cook in a water bath
The presence of sugar in the cure means that the bottled walnuts needed to be preserved in a hot water bath. Find a pan in which the filled bottles can be completely submerged. Bring the water temperature up to 88°C and hold it here for 10 minutes.
Step 5 – Maturing
Although hot cures will penetrate more quickly than cold, whichever cure and bottling method you have used, the spices will need a good length of time to penetrate the walnuts. The walnuts will absorb vinegar so after six weeks if any are completely dry top up with cold vinegar to keep them covered. They could be eaten the first Christmas after making but will be considerably better the following year and will continue to improve for up to 4 years.
Wow-Wow Sauce
When Dr William Kitchiner, scientist and enjoyer of the good things in life, died in 1827, a friend wrote of him that “to invent odd things and give them odd names was his special hobby”. This is probably as close as we shall ever come to knowing why the doctor, who invented this sauce, should have called it “Wow-wow”. The name may be derived from an exclamation at the sauce’s spiciness, or, more fancifully, since it was thought to go especially well with venison, from the warning bark of a deer. Only Kitchener knew the truth and he took his secret with him.
The recipe first appeared in his Cook’s Oracle (1817). It would be excellent served with barbequed meats.
For 4-6 people
2 oz butter
1 oz plain flour
½ pint meat stock
1 tbsp vinegar
1 tsp prepared English mustard
1 tbsp mushroom ketchup or port
1 tbsp finely chopped parsley
6 pickled walnuts, diced
Melt the butter in a pan over a low heat. Stir in the flour and cook for a couple of minutes, stirring all the time. Gradually add the stock, stirring well to avoid lumps.
When the sauce is smooth, add the vinegar, mustard and mushroom ketchup or port. Simmer again, stirring from time to time, until you have the consistency you want.
Stir in the chopped parsley and the diced pickled walnuts. Let the sauce heat through for another minute or so and serve hot.
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