From Bean to Bar: The Making of Chocolate

Chocolate begins its life on a tree that refuses to behave like most crops. Theobroma cacao — the 'food of the gods', as the botanist Linnaeus named it — grows only within about twenty degrees of the equator, and even there it is fussy. It is a delicate understorey tree that prefers the shade of taller neighbours to full, direct sunlight, and it produces its fruit in a way botanists call cauliflory: the flowers, and later the pods, sprout directly from the trunk and the thickest branches rather than from young twigs. A mature pod is about the size of a small rugby ball. It has a thick, ridged husk that turns from green to yellow, orange or crimson as it ripens, and it hangs from the trunk on a short woody stalk. Split one open and you will find thirty to fifty seeds — the cocoa beans — embedded in a layer of sweet white pulp. Ripe pods never fall from the tree of their own accord, and they must be cut by hand, usually with a machete or a curved knife on a pole, because a careless blow from a machine would destroy the cushions of tissue on the trunk from which new flowers, and therefore future harvests, grow.

A raw cocoa bean is a disappointment: fresh from the pod it is astringent and so bitter as to be inedible, with none of the flavour we associate with chocolate. That flavour has to be created, and the first and most important step is fermentation. On the farm, the beans and their clinging pulp are scooped out of the pods, heaped into wooden boxes or onto mats, covered with banana leaves and left for about six days. Wild yeasts and bacteria feed on the sugary pulp, which liquefies and drains away, and the temperature inside the heap climbs steeply. In this brief, violent chemistry the harshest compounds in the bean begin to break down and the precursors of chocolate flavour are formed. Beans that skip this stage never taste of chocolate, however skilfully they are processed later.

Fermentation leaves the beans far too wet to store, so they are next spread out in shallow layers on mats or raised tables and dried in the sun for around a week. Workers turn them regularly with wooden rakes so that they dry evenly and do not grow mould, and the moisture content falls from roughly sixty per cent to about seven. Only then are the beans bagged, graded and shipped, most often to factories on the other side of the world.

At the factory the flavour is coaxed further by roasting, which browns the beans and drives off the sharpest remaining acids. The roasted beans then pass through a winnowing machine: rollers crack them open, and the loose shells, being far lighter than the kernels, are blown away by fans, leaving behind broken fragments of pure bean known as nibs.

The nibs are then ground between steel rollers or stones. More than half of a nib's weight is fat — cocoa butter — and the heat of grinding melts it, so that what emerges is not a powder but a thick, flowing paste known as cocoa liquor. Sugar, extra cocoa butter and, for milk chocolate, dried milk are blended in, and the mixture then undergoes the strangest stage of all: conching. Invented by Rodolphe Lindt in 1879, the conche kneads and aerates the warm chocolate, in some factories for as long as three days, until the gritty particles are ground too small for the tongue to detect and the last harsh flavours evaporate; the purpose of conching, in short, is to make the chocolate smooth. Finally the liquid chocolate is tempered: it is carefully cooled and then gently reheated so that stable crystals of cocoa butter form throughout it. Well-tempered chocolate sets glossy and hard and breaks with a clean snap; badly tempered chocolate is dull, crumbly and streaked with grey.

For all the machinery at the factory end, the crop itself remains stubbornly a smallholder's plant. The great majority of the world's cocoa is grown not on large plantations but on family smallholdings of a few hectares, and two West African countries, Côte d'Ivoire and Ghana, together supply well over half of the global harvest. The tree's demands — shade, heat, humidity and endless hand labour — have so far defeated most attempts to mechanise the harvest. The bar that snaps so neatly in a European or American shop is, from the first cut of the machete to the final fold of foil, a product that still begins with a farmer, a knife and a tree that fruits from its trunk.