These days the idea of a food that is “forced” sets off alarm bells. Shouldn’t we be striving to eat what is natural, local and in season? The big exception is forced rhubarb: those electric pink stalks that are in the shops now, and are a world away from their outdoor counterparts, which can often be woodier and stringier.

Hugely popular until the Sixties, when the influx of exotic fruit threatened to eclipse it, forced rhubarb is now fashionable again, thanks to the commitment of growers and a new fascination among chefs keen to champion a high-quality artisan British food.

So highly prized has it become that, led by Janet Oldroyd Hulme, whose family has been forcing rhubarb in Yorkshire for five generations, the growers of the famous Wakefield Rhubarb Triangle have applied to the EU for protected status, to guard against “inferior” imports.

What’s forced about it?
Forcing and blanching rhubarb are different processes that are often confused. In late November many people pack straw around their rhubarb plants in the garden, and put a clay pot or a bucket over the top to block out the light, keep the plant warm and trick it into thinking it is spring.

Because it can’t photosynthesise, instead of growing green leaves it puts its energy into producing shoots that are more brightly coloured and tender than those exposed to the elements. They probably call this forcing, but in fact it is blanching. In the early 1800s it was discovered that lifting the root and using heat – as well as light deprivation – produced a lucrative early crop.

“This was the start of true forcing, in which the plant grows without soil and light by using its own energy,” says Oldroyd Hulme. By the end of the century an industry had grown up in West Yorkshire using forcing sheds heated by coal from the local pits.

What does the process involve?
The hugely labour intensive technique is the same as it has always been, except warm air has replaced coal fires. The rhubarb is grown in the fields for two years, and, after being exposed to frost, is lifted. The plants then go into the pitch black of the forcing sheds, where the moist warmth triggers the buds to grow. “You can hear them popping,” says Oldroyd Hulme.

“You have to handle the plants as if they were eggs, because the slightest bruise can introduce botrytis [a fungus that causes plant rot].” Workers use only candles to work and harvest by, and when Oldroyd Hulme shows visitors around, she says, “people say it is magical, like fairyland, or even that there is a religious feel inside the sheds”.

Where to buy: E. Oldroyd & Sons (0113-282 2245; www.yorkshirerhubarb.co.uk). Talks and tours of the sheds are available. All things rhubarb are celebrated at the Wakefield Food Festival, March 7-8 (www.wakefield.gov.uk).

Readers’ queries

I’d like to grow chillies – where can I find seeds?

The South Devon Chilli Farm will send out individual varieties (minimum order £5.50) or a collection of its ten bestsellers for £17.95 (01548 550782; www.southdevonchillifarm.co.uk).

If you have a food query, e-mail food.detective@thetimes.co.uk

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