Of all the foodstuffs which permeate our life, chocolate is perhaps the most totally identified with pleasure. A currently circulating email quips: “Nine out of 10 Britons like chocolate. The 10th lies.” To find a symbolic setting for a boy learning to make the right choices, where else could Roald Dahl turn but to Charlie and the Chocolate Factory? And when Forrest Gump, in the movie of the same name, needed an image to match his soft-centred view of life, what else could he pick but “life’s like a box of chocolates, you never know what you’re gonna get”. It was not always thus. Chocolate once held a high place in the religious world view of indigenous peoples of central and south America.

If music, as Shakespeare wrote in Twelfth Night, is the food of love, chocolate was the food of gods. It was even officially named so by 18th-century Swedish naturalist Carl Linnaeus (1707-78) who called it “theobroma”, a Greek-derived concoction of a word meaning food of the gods.

This name, augmenting the original “cacao” (also called “cocoa”) for botanists, recognised that it is not just the tongue-tingling taste of cocoa solids which has made so many of us slaves to these almond-shaped brown seeds: it is also the psychoactive ingredients such as caffeine and theobromine which mean the lady really loves Milk Tray.

Chocolate was recently found in ceramic vessels dating from 2,600 years ago in what is now northern Belize. Roasted and ground seeds from the cocoa fruit were mixed with water and poured between two vessels to get a head of foam, says Jerome Haas of Chicago’s Field Museum. These early chocoholics may have been Olmec peoples, generally considered to be the first meso-American civilisation. Soon after, Mayans in the Orinoco basin also found that cacahuquchatl (cocoa seeds) could be ground and eaten to make a great sensual experience, with an added mental buzz. When they migrated to the Yucatan peninsula of modern Mexico in ad600, the Mayans took their fondness for xocoatl (“bitter water” in Mayan) with them, cultivating the cocoa palm.

Five hundred years after that, conquering Aztecs took over cocoa cultivation, roasting and grinding the seeds, adding spices such as vanilla and hot peppers to whisk up a drink, chocolatl, which they believed conferred wisdom and power, according to their god Quetzalcoatl who had stolen a tree from paradise. The frothy liquid was used as a loving cup to celebrate 12th-century Mayan marriages; the Aztec emperor Moctezuma took a golden goblet of it - or 50, as contemporary accounts relate - before visiting his harem.

Each year, human sacrifices were made to the guardian goddesses of cocoa: Tonacatecutli, the goddess of food, and Calchiuhtlucue, the goddess of water. The victim was given a ceremonial cup of chocolatl, giving an extra dimension to the expression “I’m dying for some chocolate”. Cocoa nibs, as they are known, were used for currency, with four beans buying a rabbit and 100 a slave.

Cort s and the 16th-century Spanish conquistadors quickly adopted the thick, bitter beverage, adding sugar, allspice, cloves, cinnamon and nutmeg to make a spicy delicacy said to be an aphrodisiac, perhaps because of Moctezuma’s endorsement. For nearly a century, its manufacture was kept a Spanish secret and, since sugar and spice and all things nice were extremely expensive, one reserved only for the ruling class. Meanwhile, the beans continued to be used as currency in Latin America and the British destroyed as worthless several ships with cocoa beans as cargo.

When Princess Anne of Austria, daughter of Philip III of Spain, married King Louis XIII of France in 1615, she gave him some chocolate powder in an ornate chest. She seems to have passed on the love of chocolate to her son, Louis XIV; at any rate, it was during his reign that the passion for chocolate really kicked off in Europe.

As with most novelties, chocolate was seen to be daring. In the 17th-century, a mayor of Zurich drank it in Brussels and was so smitten that he took it home to Switzerland. Casanova and the Marquis de Sade are said to be among the more outre of its 18th-century devotees, using it to get their wicked way. The poet Pope associated it with feminine gatherings and gossip; decades later, the German poet Goethe would not travel without a supply and his own personal pot. For a long time, you could only drink it at the houses of the rich or at coffee houses, but as plantations proliferated, trade boomed and, after 1730, mechanisation made grinding smoother and quicker, the aromatic brown powder became more of a staple, less of a luxury.

In 1662, Dr Bachot, a French surgeon described chocolate as “so noble a confection, more than nectar and ambrosia, the true food of the gods”. From luxury item the drink began to be seen as a health product, as described by chef and gourmet Brillat-Savarin: “as healthful a food as it is pleasantI nourishing and easily digestedI above all helpful to people who must do a great deal of mental work.” Obviously a man who sat up late with an essay crisis and a cup of hot chocolate.

Throughout the 18th century, making cocoa was a laborious, costly business.

In 1761, a young Quaker doctor, Joseph Fry, bought a chocolate business in Bristol. Production involved roasting cocoa beans over an open charcoal fire, hand winnowing, grinding and crushing on a heated slab. The cocoa mass was mixed with flavourings and sugar in copper or tin pans, then shaped into tablets. These were not for eating, but to make a drink by placing the tablet in a cup and add hot water or milk. In 1776, one pound of Fry’s famous chocolate retailed at seven shillings and sixpence (35p), roughly equal to the average agricultural labourer’s weekly wage. When Fry died in 1787, his business passed to his widow and sons.

The big breakthrough came in 1828, when Dutch manufacturer Dutchman Conrad Van Houten invented a dry press to extract the cocoa fats, or “butter”, from the beans, more efficiently than earlier boiling processes. The resultant powder was treated with alkaline salts to make it more adaptable - it was still for making into a drink, but this was now almost instant.

Twenty years later, in 1847, Fry and sons mixed some of the cocoa butter back into the “Dutched” chocolate, added sugar to create a paste that could be moulded, and made the first commercial chocolate bars. “Five boys”, named after the sons, was one of their most famous brands, displayed at an exhibition in 1849. More discoveries, such as chocolate-coating confectionery - Fry’s Turkish Delight, anyone? - followed quickly.

Americans visiting the Great Exhibition in 1851 were amazed at the variety of confectionery on show.

Other Quaker families - Cadbury, Rowntree and Terry - were involved in chocolate-making. Cadbury’s in Birmingham first emphasised the connection between boxes of chocolate and romance, making the first heart-shaped box of chocolates in 1861. Valentine’s day was joined by Easter and Christmas as chocolate occasions. Meantime, the Cadbury dynasty founded a whole model workers’ village, Bournville, and became famous as enlightened employers.

Other famous chocolate names also date from the 19th century. The Swiss chocolate pioneers Francois-Louis Cailler and Philippe Suchard opened factories. Henri Nestle, a chemist who first developed powdered milk, and Daniel Peter combined their talents to produce the first milk chocolate bars, and Rodolphe Lindt, another Swiss, invented the “conching” process in 1879, radically changing the manufacture of chocolate and the experience of eating it. In conching, the liquor is thoroughly blended over heat for several hours, producing a much less grainy product than before. Combined with such products as fondant and praline, it melted on the tongue as well as on the stove.

In 1893, successful caramel-maker Milton Hershey attended the Chicago International Exposition, bought some German chocolate-making machinery and began making chocolate-coated caramels. In 1894, he started the Hershey Chocolate Company, producing chocolate caramels, breakfast cocoa, sweet chocolate and baking chocolate. He sold his caramel business and concentrated on such classic American bars as Almond Joy, Kisses, Mounds, Hugs, Nuggets and Reese’s Pieces. In 1897, the first published recipe for chocolate brownies appeared in a Sears Roebuck catalogue. In 1926, Joseph Draps started the Belgian Godiva business, to dominate the luxury end of the market.

Meanwhile, on the American west coast, Frank Mars set up a chocolate factory in 1911. In 1923 he invented the Milky Way and in 1936 the Mars bar (in the US, Mars is nougat and whole almonds topped with caramel and coated in chocolate, our Mars is sold as Milky Way, while our Milky Way is known as Three Musketeers). As well as Maltesers, Snickers and Twix, Mars today makes Mamp;M’s. Having seen soldiers in the Spanish Civil War eating chocolate covered with a hard sugary coating, Forrest Mars Sr devised Mamp;M’s, first sold to the public in 1941 in cardboard tubes. Its rival Smarties appeared in 1937. In 1954, the slogan “The milk chocolate melts in your mouth - not in your hand” and Mamp;M’s packaging were both trademarked.

Nowadays, with the British consuming an average of 10.3kg each a year, and with Britons spending pound;1.49 billion a year on chocolate (according to the Office for National Statistics), it seems almost true that: “There are four basic food groups: milk chocolate, dark chocolate, white chocolate, and chocolate truffles.” Celebrations, gifts, occasions demand chocolate.

Considered irresistible, it’s one luxury that poor people can afford and rich people don’t despise. Quite a victory for a tropical palm tree.

* Useful websites www.rsc.orgisbookschocolate.htm

www.erowid.orgchemicalschocolatechocolate_chemistry.shtml

www.icco.orgquestionsqindex04.htm

http:inventors.about.comlibraryinventorsblchocolate.htm

www.cadburylearningzone.co.ukhistory

http:flfl.essortment.comthehistoryofh_rizr.htm

www.geocities.comfoodedgetimeline.htm

Cultivation and processing

Cocoa palms are not the most rewarding of crops. Few trees produce fruit at the same time, and the ripe fruit, new pods and flowers appear all together. The big orange pods are delicate and easily damaged, so children are often used to pick them. Removed from the fruit, the beans have to be fermented for several days to remove bitterness, then dried to prevent spoiling.

Processing then involves roasting and shelling the beans. The alkalised kernels are ground into a paste called cocoa liquor. To separate cocoa powder from cocoa butter, hydraulic presses squeeze the liquor till the butter is extracted. To make solid chocolate, the pressed cocoa mass is mixed with added cocoa butter, sugar and milk (if required) and then kneaded “conched” for hours. It is brought to the right temperature to give it a good sheen and then poured into moulds. White chocolate uses cocoa butter but no cocoa mass.

Three types of beans are grown: forastero, which accounts for 90 per cent of the world crop; criollo, which is highly prized for aroma; and trinitario, a cross between the two. Biggest producers are the Ivory Coast (more than one million tonnes a year), Indonesia (nearly half a million tonnes), Indonesia, Ghana, Nigeria, Brazil and Cameroon. By-products include animal feed, soil mulches and cosmetics, but the largest market is for powdered and solid chocolate.

Profits in the cocoa and confectionery trades are huge, but child slave labour and terrible conditions prevail on many west African farms.

www.globalexchange.orgcampaigns fairtradecocoa A growing market for Fairtrade products, such as the tasty Dubble (www.dubble.co.uk) may reinforce the protocol aimed at ending child slavery. See also www.cafedirect.co.uk Food of love?

Among its 1,200 chemical compounds, chocolate contains:

* Caffeine, which acts as a stimulant.

* Theobromine, which stimulates the heart muscle and the nervous system.

* Phenylalanine, reputed to be a mood elevator and an anti-depressant (no conclusive proof exists yet).

In addition, certain ingredients in chocolate stimulate N-acylethanolamines (cannabinoid receptors) to produce a feeling of euphoria. However, a study by Nestle found that an individual would need to consume a 22,000lb (10,000kg) chunk of chocolate to attain any drug-like effects. Another study, by Christian Felder of the USA National Institute of Mental Health, more soberly found that a 25lb (11.4kg) piece was needed to attain a “high” for a 130lb (59kg) individual.

Chocolate also contains tryptophan, an essential amino acid involved in the production of the mood-modulating neurotransmitter serotonin. Enhanced serotonin function typically diminishes anxiety. But tryptophan can also be obtained from other sources, for example beans.

Consumption of chocolate triggers the release of endorphins, the body’s endogenous opiates. Enhanced endorphin-release reduces the chocolate-eater’s sensitivity to pain. Endorphins probably contribute to the warm inner glow induced in susceptible chocoholics.

Cocoa and chocolate bars also contain a group of neuroactive alkaloids known as tetrahydro-beta-carbolines. These are also found in beer, wine and liquor and have been linked to alcoholism. The combination makes your heart beat faster, gives you a glow of sensual pleasure, sets up an addictive hazeI well, you can see how chocolate could be linked to love. In fact, however, only small quantities of these substances show up in chocolate.

Debunking session

Myth: like red wine, dark chocolate is supposed to be good for your heart (or, chocolate is bad for heart disease and cholesterol).

Fact: research in the US claims that fat in chocolate is stearate, which is less dangerous than high-density lipid cholesterol (the bad kind).

Fact: more recently, a study of 8,000 male Harvard graduates showed that chocoholics lived longer than abstainers. This may be explained by the high levels of polyphenols and flavenoids in chocolate. Polyphenols may reduce the oxidation of low-density lipoproteins and thereby protect against heart disease. Such theories are still speculative. See www.chocolate.org, www.chemistry.about.com

Fact: chocolate is also rich in copper, deficiency of which can cause heart disease

Myth: chocolate is bad for your teeth.

Fact: sugar in chocolate bars damages teeth: regular brushing should counteract this. The cocoa butter in chocolate coats the teeth and may help prevent plaque.

Myth: chocolate is thought to cause spots and acne.

Fact: no hard facts; research shows that acne is not primarily linked to diet.

Myth: women like chocolate more than men.

Fact: acute monthly cravings for chocolate in premenstrual women may be partly explained by its rich magnesium content. Magnesium deficiency exacerbates premenstrual tension. Before menstruation, levels of progesterone are high. This hormone promotes fat storage, preventing its use as fuel; elevated levels may cause this periodic craving for fatty foods. One study reported that 91 per cent of chocolate cravings associated with the menstrual cycle occurred between ovulation and the start of menstruation. Chocolate cravings are admitted by 15 per cent of men and about 40 per cent of women.

WARNING: Chocolate can be fatal to dogs, causing fits, kidney damage and death. Regular dark chocolate is made from cocoa beans, the source of high levels of theobromine, a caffeine-like substance. White chocolate, on the other hand, is made from cocoa butter, which is safe for dogs. Dog chocolate is made from carob, which is free from theobromine, or powdered liver, which looks like chocolate to the owners. www.parkvets.com

Chemical hazards

Theobromine is a xanthine alkaloid, a methylxanthine (as is caffeine) and makes up the major alkaloid constituent of chocolate, cocoa powder and cocoa bean hulls; it is also found in cola and tea. Chocolate is obtained from the roasted seeds of the plant Theobroma cacao. The amount of theobromine in powdered cocoa varies, but it can be quite high. Usually, the darker the chocolate the higher the theobromine content. The amount of caffeine in different chocolate products is also extremely variable. For example, unsweetened baking chocolate reputedly has up to 10 times more caffeine than milk chocolate.

Theobromine affects humans similarly to caffeine, but on a lesser scale. It is mildly diuretic (increases urine production), is a mild stimulant, and relaxes the smooth muscles of the bronchi in the lungs. In the human body, theobromine levels are halved between six and 10 hours after consumption.