She returned groggy from a bout of swamp fever, but enthusiastic about peasants mincing cocoa paste by the roadside to make homespun medicines, about wild cocoa trees in virgin rain forests, about fermented beans drying in the sun and how different one kind of chocolate can be from another.
Couverture, confectioner's chocolate, comes in blocks, tablets, drops and discs. At one extreme, it can be almost black, almost bitter. At the other, white chocolate, a mixture of deodorised cocoa butter and sugar, will have no chocolate flavour whatsoever.
Eating quality depends on processing and blending, on the freshness of a product. The type of bean used and its source, its condition, its method of fermentation and drying on a plantation have an equal importance.
According to Clark, Venezuela supplies only a tiny fraction of the world's cocoa, but has five growing areas, each of which cultivates beans with a different taste. Bariovento in the east, for instance, produces Caranero Superior, a type that is reputed to have more aroma and better acidity than beans farmed near the coast.
A cocoa pod tips the scales at anything between 200g and, exceptionally, a kilogram. It contains from 25 to 75 beans, which account for a quarter of the weight. Scraped out of the husk, they are left to ferment in piles, on trays or in baskets, then dried by the sun or in special chambers.
The beans contain residual moisture, a chemical called theobromine (which is linked to claims about their health and aphrodisiac properties), protein and about 55% fat.
Couverture is a blend of ground, roasted beans (a paste from which the butter is sometimes extracted and added back), sugar and lecithin, sometimes with additional butter, sometimes with vanilla. A typical blend might contain 40% sugar and 40% cocoa butter. This may be practical for sweeter, Belgian- or English-style chocolates, but is too sugary for truffes au chocolat - truffles.
Here, Clark insists, the choice of a higher grade couverture is essential, ie, more cocoa solids, less sugar. Those which have a 55% or more cocoa butter content are adequate, but for the best results she chooses a 70%.
The range of top-class couvertures available to chefs is expanding all the time. There are three varieties of bean to choose from: Forastero, Trinitario and Criollo. The last enjoys the best reputation, but is often blended with the others. Single-plantation couverture is becoming fashionable in the same way that estate-bottled olive oil did a few years ago.
When Christopher Columbus first encountered chocolate in 1502, cocoa beans were a form of Indian currency. Ten beans bought a rabbit. Since then, the fortunes of chocolate have ebbed and flowed. From a prized drink for the privileged few, it has evolved into a commonplace snack, but the best hand-made chocolate truffles remain one of the world's great luxuries.
TYPES OF COCOA BEAN
Chocolate is made from three kinds of cocoa bean: Criollo, Forastero and Trinitario. The first, the Rolls-Royce variety, is in relatively short supply, but most couverture contains a high proportion of Forastero.
CHOICE OF COUVERTURES
Couverture contains a minimum of 35% cocoa butter, other cocoa solids, lecithin and sugar. Since a proportion of the butter may have been refined until virtually odourless and tasteless, the taste will hinge on the flavour of the ground roasted beans, their variety or blend, their quality and processing.
As with coffee beans or vanilla pods, that covers an infinite number of subtle variations. You can buy couvertures made from a single variety of bean, from a single country, or a blend. Some couverture is sweeter, some more bitter. Individual tastes may be characterised as fruity or nutty. The very finest dark couverture will be made from Criollo beans, which have a very intense lingering flavour.
Clark buys Venezuelan Carupano couverture (76% cocoa butter) as her best quality. For her mainstream chocolate making, she chooses Saboca (55%) which melts well and is easy to temper.
In most pÆ'tisseries chocolate is melted in a bowl over a bain-marie, but it can be done in a cooker or over a hotplate set at a very low temperature or, in small quantities, in a microwave oven. Dark couverture must never be heated above 55ÂºC. Milk chocolate couverture must never be heated above 50ÂºC. Any higher temperature will spoil the flavour.
For standard-sized truffles use a piping bag with a 12ml plain tube. Pipe the ganache (see recipe) on to a sheet of silicone paper. It should be set firm enough to pipe, but neither runny nor hard. Pipe small mounds on to the paper, roughly 10g each.
Transfer the truffles to a fridge to harden. The mixture can also be piped in strips (10ml tube). This is what Clark does for her Champagne truffles.
Once the mounds of truffle mixture have hardened, they can be rolled into shape. This is easier working with cool hands on a marble surface. A little cornflour on the hands prevents the truffles from sticking. For beginners, truffles containing butter are easier to roll. Those without are more fragile and require a delicate touch. Before dipping truffles in tempered couverture and dusting them with cocoa powder, they should be hardened off in the fridge.
DIPPING and DUSTING
Stand the bowl containing melted couverture at 32ÂºC on a hoop so that the chocolate tilts towards the front. Dip the truffle and coat it thoroughly, rolling it against the inside edge to ensure that the coating is even and not too thick. Transfer to a sheet of silicone paper and leave to set. Dust with cocoa powder.
Note that cocoa powder quality varies from low fat (8%) to high (20%) in the same way that couverture does. Buy the best, it does make a difference.
Chocolate shells filled with ganache can be dipped in the same way using a dipping tool. Dip the shells in couverture, transfer to a cooling wire and rake the surface of the couverture with a three- or four-pronged dipping fork.
Only put 10 dipped chocolates on a cooling wire at one time or they will set and stick to the wire. Dipped shells should be allowed to set in a cool environment, around 10ÂºC.
The maximum storage period for fresh truffles is a fortnight, but they are definitely better when eaten straight away. For reasons of hygiene, chocolate makers often store them in a fridge, but this isn't ideal, because they sweat and lose shine when taken out. A cool larder is better. n