There are many, keenly noted, early warning signs that British springtime is upon us. Look past the blossom-laden trees and clumps of wisteria to the appearance of shiny stalks of crimson rhubarb, the first homegrown fruit to grace our tables. "Early English strawberries are likely to have been greenhoused and the gooseberries are not quite ready. Rhubarb is the first fruit you can put on your menu to say, 'The season has changed. Spring has arrived'," explains Arthur Potts-Dawson, chef and co-owner of Acorn House and the Waterhouse restaurants.
In fact the jury is out as to whether rhubarb is a fruit or a vegetable. It looks like sticks of celery dressed in their pink Sunday best, blushing from the first few washes of early sun glimpsed through the plant's dense leafy canopy after a long winter underground. You can't eat it raw because the green leaves are highly poisonous, and the sticks themselves are almost caustically bitter before they are softened with cooking and sweetened with sugar. Baked in a crumble, rhubarb is a staple Sunday lunch pud. Cooked well, it is a meltingly soft treat, perfect for a sauce, puree, filling or on its own. The tartness adds kick and character. But its naturally sour flavour and potentially stringy texture means it is adored and despised with equal vigour.
Rhubarb's awkward positioning between fruit and vegetable, sweet and tart, has gained it a reputation as something as an oddity among British produce. Russell Brand uses the phrase "'tis Rhubarb" to describe something as nonsense. The Monty Python clan accorded rhubarb a venerable place in British comedy history with John Cleese's eulogistic "Rhubarb Tart Song", which celebrates the fruit as a favourite of philosophers and poets: "Eternal happiness is rhubarb tart/A rhubarb what? A rhubarb tart!/A Jean-Paul who? A Jean-Paul Sartre!/Eternal happiness is rhubarb tart."
Our love-hate relationship with rhubarb began in the Victorian era, when it found its way to the UK from Asia via ancient Chinese trading routes. Though rhubarb never became as indispensable a part of British culture as tea, it was assimilated into our farms and allotments thanks to its hardy structure. When the supply from Asia dried up and Victorian growers were struggling to meet demand, a chance discovery led to the method that produces "forced" rhubarb, grown in darkness in heated sheds. Until the turn of the century, rhubarb production in this country had largely retreated to Yorkshire's "rhubarb triangle", where a scattering of growers straddling Leeds, Wakefield and Bradford "force" rhubarb from late winter until early spring. Forced stalks are thinner, sweeter and more fragile than their outdoor brethren, and are picked by candlelight for a few months starting in February, when they will begin to appear on shelves and menus as a pricey sweet treat.
The industry was sabotaged by the growth of air-freighted, season-free produce. Rhubarb was priced out of the market by imported exotic fruits and only a dozen or so growers remain in Yorkshire. They are campaigning to promote their variety as "champagne rhubarb" to explain the cost of their intensively produced 'barb.
Unforced rhubarb has a sharper flavour, thicker stems and a coarser texture. Grower Jono Smales sells most of his organic crop to Abel & Cole for use in their delivery boxes. His New Forest farm, Lyburn, has a head start on the rest of the country, thanks to its warm coastal microclimate and his first crop is just out of the ground, with another to come in six to eight weeks.
Rhubarb is not for the impatient gardener. Smales puts the plants underground in October, where they remain for 18 months before they can be harvested for the first time. From then on, they can be harvested on alternate years. Even in the second year, explains Guy Watson, the owner of Riverford Farm and founder of its organic box scheme, the plants should be picked "only lightly, to allow the roots to build up strength".
One of its major advantages is that the same rhubarb crown, as the underground root is called, can bear fruit for around ten years. It can then be split in two, replanted, and bear fruit every other year again for another ten years. One crown can be treated in this way for up to 50 years. Watson recommends a variety called Timperley Early, or Sutton Seedless as a later option.
Smales admits that rhubarb "is not everybody's cup of tea", and says it often loses out with consumers to sweeter strawberries and raspberries. In comparison to the ubiquitous strawberries and cream of the summer season, a glass dish heaped with rhubarb and custard is a rare treat.
Attempts to kickstart the rhubarb market have emphasised its qualities as a health food. It's said to stimulate the metabolism and contains few calories. High levels of calcium and vitamin C made it an important part of our wartime diet and it's used in Chinese medicine as both a laxative and to treat diarrhoea, in different formulations. Anyone who hates the stuff may feel vindicated to learn that it is also used as an insecticide and a metal cleaner.
The nationwide rhubarb revival began in recent years when traditional British pies, crumbles, cobblers, tarts, jellies and trifles were welcomed back onto sophisticated menus, taking priority over fancier continental offerings once more. Chefs learnt to appreciate its sharp, unusual flavour and use it in savoury dishes to complement meat. Potts-Dawson recommends pairing it with mackerel, because rhubarb's acidity goes well with fatty, oily fish, and currently has twice-cooked pork belly with rhubarb compote on his tasting menu. He also whips it into a syrup with sugar to make the base for rhubarb bellinis and roasts it in chunks under a blanket of sugar and greaseproof paper to transform into sauces, chutneys and jams. Impress guests with Potts-Dawson's take on lemonade, "rhubarbade", which can be made in minutes by diluting a sugary rhubarb syrup with water.
Tom Aikens, who will be setting up an outpost of his restaurant Tom's Kitchen at the Taste of London food festival in Regent's Park next month, uses forced champagne rhubarb for delicate desserts, but recommends the outdoor variety for crumbles, crisps and chutneys. He once did rhubarb the honour of finessing it into a compote and serving alongside foie gras.
Rhubarb is rarely credited for the glamour it brings to plain, creamy fools or the tang it can add to pork or fish. Its reputation may be cemented as a downhome ingredient, fit for filling crumbles or for bearing weighty dollops of custard (arguably what it does best), but exploring its savoury potential will allow enthusiasts, and everyone else, to start to see it with fresh eyes.
At the sharp end: Rhubarb recipes
Rhubarb Butter Sauce for Fish
Try serving this with salmon cooked by placing it on an elderflower head in a baking parchment parcel with a dash of white wine, then baking in a hot oven so the bag puffs up and the salmon steams inside. It's also good with other oily fish and with pork.
500g rhubarb, cut into batons
2 teaspoons sugar
Juice and grated zest of 1 orange
150ml fish stock
40g chilled butter, cut into small pieces
Put the rhubarb, sugar, orange juice and zest in a pan and cook gently for about 15 minutes, until the rhubarb has broken down into a purée. Meanwhile, in a separate pan, boil the fish stock until reduced by half its volume. Stir in the rhubarb, season and cook for five minutes, then push through a sieve into a clean pan. Just before serving, heat the sauce and whisk in the pieces of butter a few at a time to give a glossy finish. Season to taste.
Riverford Farm Cook Book (Fourth Estate, £16.99), www.riverford.co.uk
Mackerel with Rhubarb and Cider
Fresh mackerel fillets
4 bay leaves
120 ml dry cider
225g fresh rhubarb, chopped
Half a teaspoon lemon juice
25g brown sugar
Pinch of nutmeg
Preheat the over to 180C/gas mark 4. Season the fillets with salt and pepper then place a bay leaf on each and roll up. Put in shallow ovenproof dish, pour over half the cider and dot with butter. Cover with foil or a lid and bake for 30 minutes, until tender. Meanwhile, place the remaining cider, rhubarb, lemon juice, brown sugar and nutmeg in a pan. Bring to the boil then simmer for 20-25 minutes, stirring from time to time, until soft and pureed. Drizzle the sauce onto the fish and serve on a warm serving plate.
You could use some champagne instead of some of the water for a very special sorbet. At Arthur Potts-Dawson's Acorn House restaurant, this is served with biscotti.
1kg forced rhubarb
250g caster sugar
250ml filtered water
5 juniper berries
Put all the ingredients together in a saucepan, cover and cook until soft, but without any evaporation. Turn off the heat and allow to cool. Purée the mixture in a food processor. Check for sweetness, adding a little more sugar if necessary.
Pour into an ice cream machine and churn until pink and fluffy, or freeze in suitable containers, mixing every now and again (more of a granita that a sorbet, but still delicious).
The Acorn House Cookbook by Arthur Potts-Dawson (Hodder & Stoughton, £20)