Even more astonishingly, a London factory sells an incredible 300 tons of them a week. Indeed, it is the largest bean-sprout factory in the world outside Japan (where they eat 80 times as much as we do).
It seems only yesterday (the 1970s actually) that sprouted seeds and beans first extended their influence beyond Britain's 4,500-odd Chinese restaurants and takeaways. They surfaced as a major plank of the American macrobiotic, whole earth, wholefood movement, mostly to be eaten raw in salads.
A nation accustomed to eating mustard-and-cress sandwiches since Victorian times, we took to them with interest. There weren't many seeds we didn't try and grow in those heady days of the Seventies: alfalfa seed and fenugreek, which grow very fast; chick peas and soy beans, whose shoots don't detach from the bean, making them more than a bit chewy.
We sprouted tiny red Japanese adzuki beans, lentils of all colours, cowpeas, sunflower seeds, wheat. Not to mention barley. We Britons should certainly know a thing or two about sprouting barley, having done so for several centuries. Not to eat raw, but for roasting (malting), thus turning the starch to sugar (maltose) in order to make the liquor (wort) which we ferment to make good old English ale.
Vegetarians, especially vegans, embraced these little seed shoots enthusiastically, seeing them as power packs promising the benefits of good nutrition and energy. Perfectly valid claims, it so happens. And so natural. The whole bean and nothing but the bean, nothing added but water, warmth, air.
Sprouted seeds have a nutritional value half-way between raw seeds and the mature vege-tables they might have become. They have a surprisingly high proportion of protein, over 35 per cent, so are specially valuable where other sources of nutrition are limited.
Bruce Cost, the encyclopaedist of oriental food, says the Chinese developed bean sprouts more than 300 years ago, to provide precious winter sustenance. "One can surmise that the Chinese grew them as a sort of instant vege- table, one that doesn't require a patch of land and proper weather. Few other vegetables can be harvested in the dead of winter."
Sprouted seeds also provide minerals, especially calcium, phosphorous and iron, which germination makes more easily assimilable because of an enzyme reaction. Not to mention valuable B vitamins and a high percentage of vitamin C.
It seems unlikely that the majority of today's well-to-do supermarket customers are stacking up nutritional brownie points. So what prompts this bean boom? Over to Park Royal (a huge West London trading estate). Here is J Pao Ltd, Bean Sprout Producers, a three-acre site which in the 1930s accommodated the whole of Standard Vanguard's car production.
Martin Robinson, 42, is managing director of this remarkable company, which was started 32 years ago by Joseph Yee Ching Pao, son of a Shanghai industrialist. Mr Robinson explains that the entrepreneurial Mr Pao actually studied electronics at Southampton University and made a breakthrough as an inventor (patenting the polycone loudspeaker system).
It was the technical challenge that first led Mr Pao to growing bean sprouts, which he did in his garage in Kingston. As business grew he moved to a lock-up mews in Paddington and then a 100-year-old former laundry in Neasden, before settling here.
The present fashionability of the bean sprout, Mr Robinson considers, is a response to the needs of a modern lifestyle. It's cheap, nourishing, healthy and quick. That is to say it cooks in seconds rather than minutes. The stir-fry has become a "naturalised" British dish, he says, and for some years it has been promoted in nearly every food magazine and TV programme. "Everyone seems to have a wok and knows how to use it," he says, "unlike the Swiss fondue set everyone buys and uses only once."
Fifteen years ago J Pao was doing bulk business, 10lb bags sold wholesale for the Chinese market. Safeway were first to order family-sized portions, and others followed. "Then three years ago," says Mr Robinson, "Quorn decided to do a big spend, pushing their product as healthy, easy and quick, focusing on stir-fries. Suddenly all their ads featured bean sprouts."
Mr Robinson takes me on a tour of the factory. A sign of Mr Pao's ingenuity is that he has set aside a corner of the site as a trading post. Before dawn, every day, vans converge with other Chinese provisions - freshly- made bean curd and noodles, closed cup mushrooms, pak choi cabbage, pork belly, even delicacies such as webbed duck's feet (for steaming) and fish eyes from Billingsgate.
Mr Pao utilises about 50 self-employed van drivers to trade with some 2,000 Chinese outlets (from Manchester to Cornwall), based on their insistence on fresh bean sprouts every two days.
Mr Robinson leads me between banks of stainless steel equipment. In our wellies we paddle across lakes and rivers, evading showers and waterfalls that feed the germinating system. "We are the third major user of water in the area, after Guinness and Fullers, I believe."
The process is simple enough. Green mung beans from Thailand are spread inches deep on draining trays at the bottom of four-foot deep plastic containers, aerated from below. The tanks, 60 to each darkened room, are showered with tepid water at intervals. The bean shoots generate ectothermic heat, increasing the warmth and humidity in which they thrive. After six days, a heaving mass of shoots bursts from the top, a bushy hat like neat topiary.
The contents of each bin are tipped into a deep tank of water, churned vigorously to shake off the bean husks. They move along conveyor belts for further stages of rinsing and washing under jet sprays, finally dropping into a miniature waterfall with a force that snaps off their slender roots, like so many tadpole tails.
Each stage is as precise as an electronics engineer can devise. "Achieving the perfect bean is a black art," says Mr Robinson mysteriously, leading me to meet the wizard himself, Mr Pao, who is now the chairman.
In a darkened control room at the heart of these wetlands, beaming behind his thick glasses, surrounded by thousands of pieces of blinking electronic gadgetry, stands Chairman Pao - more like a Dr Who, though, or perhaps a demented scientist dedicated to dominating the world by breeding this new life form.
He indicates the specimens of the would-be master race, fat white shoots with curling tendrils and tails of spermatozoa. Botany lesson. "The aim," he gleams, "is to grow a uniform shoot (known as the hypercotyle) to a length of 5.5 cms to 6 cms long, and 4mm in diameter." Since he started his life's work, he has been able to increase the length and diameter of the bean sprout by 30 per cent, effectively increasing growing time from four days to six.
Supermarkets look to ways of extending shelf-life, which is a problem. After harvesting, the sprouts starve to death if deprived of air. Over- exposed to air, they also die. His solution is to pack them in bags of micro-porous film.
"We have to minimise bacterial activity. Our trials show that 55 per cent of bacterial activity takes place in the hood covering the first pair of leaves [the cotlydon], and 30 per cent in the thin root."He delicately plucks the cotlydon from the leaves. He snaps off the root. He explains that the vigorous washing process is devised to do just this. But handling must be precise, for if the main shoot is broken it will trigger its bacterial activity (low though it is, 15 per cent).
It's becoming clear that growing bean sprouts is but a by-product of Mr Pao's engineering genius. So it comes as no surprise to discover that he has been exporting his technology to Japan. They have recently opened six pounds 5m bean- sprout factories built to his specifications.
A mighty achievement, you might think. "My wife doesn't," smiles Mr Pao. "She says, why do I waste my time growing a cheap vegetable when I could be growing truffles?"
So to the question. To cook them or eat them raw? Veggie guru Colin Spencer (nature green in tooth and paw) advocates the raw. Enjoy the crunch they give to sandwiches, he says, with the savoury addition of anchovy spread, or yeast extract with slivers of onion, or with avocado and rocket leaves. Or eat them as they are with sea salt, lemon juice and maybe walnut oil.
I prefer them cooked. That is to say, fast-cooked in a little groundnut oil in a white-hot wok for only 30 seconds or so, tossed with a little chopped garlic and shredded ginger, plus salt and black pepper. To finish, a tablespoon of light soy sauce, and a teaspoon of sesame soil.
Here is a typical instant dish I learnt from the Chinese cook Ken Hom.
CANTONESE STIR FRY
450g/1lb pack of dried or fresh egg noodles
350g/12oz bean sprouts
50g/134oz cured ham (Parma or Spanish serrano), sliced into 5cm lengths
2 teaspoons sesame oil
For the sauce:
300ml/10fl oz chicken stock
2 tablespoons dark soy sauce
1 tablespoon light soy sauce
2 tablespoons rice wine, or dry sherry
1 tablespoon finely chopped garlic
3 tablespoons finely chopped spring onions
Cook the noodles in plenty of salted boiling water for three to five minutes. Drain. Leave the noodles to stand in cold water until ready to use (they can be left for up to an hour).
Heat a wok. Combine the sauce ingredients and the noodles and heat together. Add the bean sprouts, ham and sesame oil, stir-frying for about three minutes, or until everything is completely hot. Serve in a large bowl at once. !Reuse content