This blog was written by Helen Bond, State Registered Dietitian
For me, harvest time is all about picking apples from the Bramley apple trees in my South Derbyshire garden, but this year, I was invited by the California Walnut Commission to put down my fruit crates and experience a walnut harvest first hand. The chance to see the walnut groves in the California sunshine, and find out how traditional and modern processes combine to get one of our favourite tree nuts from orchard to market, was indeed a ‘cracking’ opportunity.
California’s walnut wonderland
Before we get to the nutritional benefits of walnuts, it’s time for a little bit of geography! Did you know California is the centre for walnut farming? There are currently 315,000 acres of walnuts orchards across California’s Central Valley supplying 67 per cent of the world’s walnut trade – thanks to it’s rich, fertile soils with sunny climates, and a plentiful of fresh melt water straight from the Sierra Mountains.
Walnut orchards are planted in late winter through to early spring, in rows 24ft by 24ft apart (108 trees per acre) with different varieties of English walnuts (Chandler, Hartley, Howard, Tulare, Serr and Vina etc.) being grafted onto one of several rootstocks chosen for their disease resistance and suitability to the soil. Walnut growers need to be attentive and patient, as whilst young trees may produce a few walnuts, they are not considered ready for harvesting until the walnut trees are about four years old, and do not reach full productivity until they are 8 to 10 years old.
A walnut in disguise!
Before this tour, I could barely decipher a walnut from an almond tree, much less their hard brown shells aren’t really what you’d see hanging from walnut trees. In real life, on the branch, walnut shells are sheathed in leathery green hulls, as if trying to disguise themselves as kiwi fruits!
It’s harvest time
When the weather cools a little in early September, the drying green hulls begin to brown and split open, baring the familiar in-shell walnuts. It’s time for the walnut harvest to begin, and it continues right through to mid-November! Once upon a time, walnut picking was done manually with wooden poles to remove walnuts that didn’t fall naturally, now mechanical shakers are brought in to vigorously shake each of the trees until the ripe walnuts fall to the ground. It literally looked like it’s raining walnuts!
Next, it’s the turn of the sweepers, which use a powerful combo of air blowers and rotating flaps to sweep the walnuts into rows, so that mechanical harvesters can gather them up, and transport them for processing.
To be shelled or not to be shelled – that is the question?
Once any remaining hulls, as well as any leaves and sticks, have been removed, they are given a bath and air-dried to about a 8% water content to protect their quality during storage. Now the walnuts are divided into ‘in-shell’ walnuts, and those that are run through a shelling line where they are mechanically cracked – ‘shelled walnuts’. Walnuts are then separated into different sizes (jumbo, large, medium or baby) and colours – in Germany, China and Turkey larger in-shell walnuts with a lighter colour are the more desirable, whereas food manufactures enjoy shelled walnut pieces and darker coloured walnuts are perfect for walnut oils. After a final check by hand, the walnuts are ready to be shipped to buyers around the world or stored until needed.
Keep it in the family….
There are over 4,800 + walnut farms, most of which are family run farms, passed down through the generations and close to 100 walnut processors. There is no waste. The walnut shells can be used to make anything from facial scrubs to landscape material, the outer hull is returned to the orchard – where it quickly decomposes, contributing orchard nutrients – or ground up and used as compost. At the end of the walnut tree lives, they are ground up and used to make energy.
Mother nature wraps them up well!
For something so nutritious and delicious, it is amazing that Mother Nature provides two layers of protection – the hull and the shell – before you arrive at the prize walnut. These brain-shaped, wrinkly wonders may not look like much, but walnuts are an Aladdin’s cave of plant-based goodness:
• Are high in cholesterol-lowering unsaturated fat and heart vitamin B1
• Contain the highest amount of plant-based omega-3 fats (Alpha Linolenic acid) out of any of the nine tree nuts
• Contain 4.4g of plant based protein per 30g portion – particularly useful for vegetarians and vegans
• Provide 1.4 g of gut healthy and satiating fibre per portion
• Only contain naturally occurring sugars
• Provide 10 vitamins and minerals, which support healthy energy release
• Are rich in copper and a good source of zinc, which support a healthy immune system
• Are rich in phosphorus, manganese and magnesium, and also provide zinc – all of which help maintain bone health
• Are rich in B6 and a source of iron which helps combat tiredness and fatigue
• Are rich in copper and a source of zinc, which help maintain healthy skin, and hair
• Are a source of iron and zinc, which help support the brain’s daily functions
Time to crack open the walnuts
I have always been a fan of walnuts, so I didn’t need convincing about the mild and naturally sweet taste of California walnuts, but there is something about eating them straight from the tree that makes them taste even more delightful. I ate far more than the suggested 30 grams (or a handful)!
Walnuts are a perfect on the go snack, but as I have sampled on this Walnut Harvest tour, they’re equally delicious and nutritious – raw or roasted, whole, halved or crushed, sweet or savoury – sprinkled over your morning porridge or muesli, made into a scrumptious chocolate walnut ganache torte, or simply tossed into a green bean salad. So, if you’re looking for a healthy snack or ingredient that will keep your taste buds satisfied and you’ll feel good about eating, it’s time to dust off your Christmas nutcrackers!