Rhubarb is a plant in the dock family, with large, green canopy leaves, and edible stalks. Rhubarb is traditionally used in sweet recipes and, increasingly, in savoury dishes too - its unique tangy, sour flavour means that rhubarb works just as well when mixed with sugar in a sweet pie as it does in a sharp pickle.
While rhubarb is deeply engrained in British cuisine - stewed rhubarb, rhubarb crumble with custard and rhubarb cobbler with clotted cream have graced many a Sunday lunch table - rhubarb actually originated in northern China, where records show the medicinal plant being used to cure gut, liver and lung problems as early as 2700BC.
It's thought that Venetian traveller, Marco Polo, first brought the plant to Europe in the thirteenth century. By 1657, rhubarb's miracle medicinal properties meant that in England, it was worth three times the price of opium. It wasn't until the mid-nineteenth century though, that rhubarb began to creep into kitchens – firstly in a sweet context and then as a savoury condiment, with rhubarb relishes becoming a popular accompaniment to mackerel and venison.
A huge percentage of Britain's rhubarb production is concentrated in a 9-square-mile region in Yorkshire known as 'The Rhubarb Triangle' – an area which was awarded Protected Designation of Origin (PDO) in 2010. The quality soil and unique climate makes for the perfect growing environment, plus Yorkshire had great rail links to London which was important during the days when the capital's demand for the stalk was insatiable. Indeed, in the late-nineteenth and early-twentieth century 'The Rhubarb Express' was a daily train which ran between Ardsley and London during rhubarb season, transporting 100 - 200 tons of the stalk to Spitalfields and Covent Garden Market each day.
British rhubarb is cultivated in two different ways, which means that there are two different rhubarb seasons.
Firstly, the 'forced rhubarb' season, which runs from Christmas to Easter. 'Forcing' rhubarb is an early nineteenth-century technique, employed by most Yorkshire rhubarb farmers. It involves growing rhubarb in warm, dark 'forcing sheds' – which encourages early growth – and then harvesting by candle light. In doing this, the tender pink stalks reach 20 - 30cm early on in the year.
The second rhubarb season comes later on in the year, when garden or field grown rhubarb naturally ripens in full sunlight. Garden-grown rhubarb typically flourishes from April to September.
Many consider the taste of forced rhubarb to be sweeter and the pink stems to be more tender than garden-grown rhubarb.
Garden-grown varieties are generally greener with a more robust flavour – varying from mild to brilliantly 'rhubarby', with textures ranging from tender to stringy, particularly if left on the plant for too long. 'Red Champagne' and 'Valentine' are popular late-spring varieties in the UK. 'Victoria' is a traditionalist's choice and arrives later on in the season.
Rhubarb is most commonly packaged as a bundle of leafless stems. They should be rigid and unbruised. Any white marks, floppy stems or sliminess indicate that it may have been a while since the rhubarb was picked. Farm shops or farmers markets may sell rhubarb with leaves attached – discard these before cooking, and don't feed them to any livestock or pets as the leaves are toxic.
Fresh rhubarb will keep for a week if refrigerated. To freeze bumper rhubarb crops, cut the stems into 1-inch sections and quickly blanch in boiling water. Chill the rhubarb chunks by running them under a continuous stream of cold water, then dry and freeze laid out on trays before tipping into bags or tubs for easy storage.
Start by discarding the toxic leaves, if still attached. Compost or dispose of these carefully as they are poisonous to pets and livestock.
Wash any residual soil off the rhubarb stems. Some rhubarb varieties are prone to being stringy, and rhubarb which has been left too long on the plant can also develop a 'stringiness' – if this occurs, pull away any thick, fibrous strands before cooking. 'Peeling' is rarely necessary.
Most recipes require the rhubarb to be cut into batons. Using a paring knife, top and tail the stem, slice at an angle into the size that the recipe requires – this could vary from 1-inch chunks for quick-stewed rhubarb to longer batons for roasting or poaching.
Rhubarb used to be eaten raw. People dipped the root into a bowl of sugar and bit into it like a carrot – in fact, it's said that rhubarb with sugar was the inspiration behind sherbet dip dabs. It's more conventional to slow cook rhubarb though, until the root is soft and juicy. Poaching, stewing and roasting are the most common techniques but pickling or even cooking rhubarb sous vide are all good options too.
As rhubarb cooks it releases a lot of moisture, so there's rarely any need to add much extra liquid. Rhubarb's flavour means that it's difficult to overpower, so don't shy away from other strong ingredients like ginger, cardamom or star anise.
The stalk's signature sourness does mean that a sweetener like sugar, honey or agave syrup is used in most recipes to balance the flavour. Tarts are often served with a sweet custard, cream or ice cream, and rhubarb pickles or chutney often use a hefty dose of sugar to counter its tart flavour.
Rhubarb is generally roasted or stewed with sugar, honey, agave syrup or soft sweet fruits and cooked rhubarb is often combined with cream in a panna cotta or trifle. It's commonly cooked in a sweet pastry, put under a crumble topping or alongside a posset. An increasingly popular use for rhubarb is to incorporate it into a custard for a semifreddo, or even a sugar syrup for a sorbet or granita.
Tangy rhubarb is often paired with similarly robust flavours like ginger, cardamom, star anise, cinnamon, rose petals, cloves or orange peel. Although it is most frequently seen in a dessert context, rhubarb can be served with yoghurt and granola for breakfasts, added to smoothies and is increasingly used as a savoury condiment. Pickled rhubarb, rhubarb chutney or rhubarb relish is delicious served alongside mackerel, venison, pork or with platters of cold meats or cheeses.