How chocolate is made?
The tropical cacao tree
Chocolate is made from the bean of the cacao tree, a species native to Central and South America and standing at between 10 and 15 m tall. It grows best in tropical conditions, at low altitude (between 0 and 800 m above sea level), requiring a temperature between 25 and 30°C and relative humidity of 85%.
Unusually, its fruit – the cocoa pod – grows along the trunk and on the larger branches and dries on the tree, never falling to the ground. It is harvested twice a year in some regions, and all year round in others.
In botanical terms, there are three varieties of cacao tree, plus one hybrid: the “criollo”, the “forastero” and the “nacional”, plus the hybrid “trinitario”. From a commercial perspective, the “criollo”, “forastero” and “trinitario” varieties are the most commonly cultivated. Each of these varieties has its own unique characteristics.
- Criollo: this cacao tree is best known for the quality of its flavours. The criollo produces a low yield and is highly vulnerable to disease. Its pointed, reddish pods are extremely sought after. This variety accounts for around just 5% of total global production. The criollo was the first variety discovered by Spanish conquistadors on the coast of Mexico, and is now mainly found in Central America, Mexico, Java and Madagascar. In Spanish, the word criollo means “creole” or “crude”. The criollo variety is extremely popular among chocolate makers and is used to make fine-quality chocolates.
- Forastero: the forastero variety has a powerful flavour and a pronounced bitterness. It accounts for between 75 and 80% of total global production. It is a hardy, high-yield variety with limited vulnerability to disease. Its pods are yellow and smooth. The forastero was the second variety discovered by Spanish conquistadors in the Amazon rainforest, and is now cultivated in Brazil, Ecuador, Martinique, French Guiana, West Africa, Indonesia and various islands in South-East Asia. In Spanish, the word forastero means “foreign”.
- Nacional: similar in appearance to the forastero, the nacional variety has floral notes. It accounts for just 0.002% of the global market. The nacional was the third variety discovered by Spanish conquistadors in Ecuador, and is now found in the forests in the foothills of the Andes. The name nacional was given by Ecuadorians, who are extremely proud of its floral notes.
- Trinitario: this natural hybrid of the criollo and forastero varieties combines the flavoursome quality of the criollo and the yield and hardiness of the forastero. Following the destruction of criollo plantations on Trinidad, the Spanish conquistadors replanted forastero trees, leading to natural hybridisation between the two varieties. Today, the trinitario accounts for between 15 and 20% of total global cocoa production. It is grown worldwide, particularly in the Caribbean, Central America, East Africa and islands in the Indian Ocean.
This process is performed on the cacao tree plantation itself. The fruit (pod) is harvested when fully ripe and opened using a machete or club, to extract beans encased in a white pulp known as “mucilage”. The beans are removed from the central axis then sorted.
The beans are then placed in trays and covered with banana tree leaves for between three and six days. The beans, still encased in pulp, undergo an initial process of natural fermentation, both anaerobic (without the presence of air or oxygen) and exothermic (releasing heat). Other plantations leave the beans in piles or use baskets, depending on the resources available to them. The temperature varies between 45 and 50°C. The beans are mixed regularly to allow air to circulate. The acidic, sugary pulp of the pods turns to alcohol during this phase. The fermentation process is identical to that used for grape must. A second (lactic) fermentation process then occurs rapidly. At this stage, the juices run and air penetrates into the piles of beans, leading to a third (acetic) fermentation process. The high temperature kills the germ in the cocoa bean. The beans change colour during this phase. When harvested, they are white or purple in colour. After fermentation, they turn to a chocolate brown colour.
The fermentation process removes the pulp surrounding the beans, reduces the bitter, astringent taste and promotes the initial development of the characteristic flavour. This is a critical phase that determines the final taste of the chocolate.
During this phase, the cocoa beans are still around 60% moisture. This level must be reduced to 7% for conservation and transport purposes. The beans are then dried in the sun or in drying rooms for around 15 days, and are then washed (especially Madagascar). They are turned on a regular basis in order to promote uniform drying. The drying process, just like the fermentation process, has an impact on the flavour of the cocoa. Once fermented and dried, the beans turn brown in colour.
Following this phase, the beans are sorted then shipped. The remaining phases of the production process occur in the chocolate factory.
As with coffee, the cocoa beans are roasted. This is an important and extremely delicate phase, the aim of which is to bring out the full flavours of the bean without burning it. The roasting process develops the typical flavour of chocolate.
This phase occurs once the beans have been cleaned, in a roaster. They are roasted for between 20 and 50 minutes, at between 120 and 140°C. The duration and temperature differ according to the variety of bean used and the desired flavours. The temperature and duration are reduced for fine-quality cocoa beans, in order to preserve the quality of their flavours. The roasting process also reduces the moisture content of the beans from 7% to 2%.
Crushing and grinding
Once roasted, the beans are ground into small pieces, known as nibs. The nibs are then ground again into a paste, also known as cocoa mass. This paste is then mixed with sugar and once again placed through a grinder containing successively tighter cylinders, to reduce the grain texture. This phase determines the final texture of the product.
Cocoa butter, press cake and powder
The cocoa butter may be separated from the cocoa mass by pressing, to create press cake. This dry residue is used to produce cocoa powder, which can then be made soluble via an alkalinisation process invented in the 19th century by Dutch chemist and chocolate maker Conrad van Houten.
In 1879, Rodolphe Lindt invented the “conching” process, which is used to extract the remaining moisture and volatile acids. The material is subjected to a long mixing process at a temperature of around 80°C, resulting in a highly uniform, smooth and creamy paste. This process helps to bring out the flavours of the chocolate. Cocoa butter may be added at this stage to produce couverture chocolate.
Addition of ingredients
The aim of the previous phases is to produce cocoa mass. Various ingredients must then be added to this cocoa mass depending on the type of chocolate required. The more sugar is added, the lower the cocoa content.
- To obtain dark chocolate, sugar is added to the cocoa paste, along with cocoa butter (or other vegetable fat) to create a creamier texture, where applicable.
- To obtain milk chocolate, cocoa butter (or other vegetable fat), powdered milk and sugar are added to the cocoa paste.
- To obtain white chocolate, only cocoa butter is used, to which are added powdered milk and sugar. White chocolate contains no cocoa.
- Flavourings or spices are often added to all types of chocolate – often vanilla, but also other spices.
On 15 March 2000, under pressure from the chocolate industry, the European Community adopted the “Chocolate Directive”. Under this directive, manufacturers are permitted to use other vegetable fats, less expensive than cocoa butter, to make chocolate, up to a limit of 5% of the total weight of the finished product. In order to satisfy demand from connoisseurs, some brands have created their own “100% cocoa butter” labels to indicate certain high-quality chocolates made to the traditional cocoa-based recipe.
Tempering and moulding
The tempering process involves transforming the cocoa butter into its most stable crystalline form. Cocoa butter consists of five different fatty molecules, each of which melts at a different temperature (between 26 and 31°C). This mixture makes the chocolate extremely crystalline, i.e. it can crystallise in six different forms. The aim of tempering is to get the chocolate to crystallise in its most stable form, i.e. to form so-called “beta” crystals.
Once cooled, the tempering process gives the chocolate a shiny and smooth appearance, its characteristic hardness and creaminess, and a longer shelf life.