Cocoa is obtained from the fruits of the cocoa tree (Theobroma cacao). This tree is native to Central and South America but is now cultivated in Africa and parts of South Asia. In fact, Africa is the world’s leading cocoa producer. The final characteristics of cocoa-derived products depend on the variety used and its origin. Although more aromatic varieties exist, the majority of the world’s cocoa comes from the Forastero variety. However, edaphoclimatic conditions also significantly influence cocoa, leading to a high importance placed on its origin in certain markets.

The cocoa tree’s fruit is oval and contains between 20 and 40 seeds, or cocoa beans, covered by a mucilaginous rosy substance. In the countries of origin, the fruit’s interior is exposed to the open air and allowed to ferment for just under a week. During this process, enzymatic action on proteins and sugars generates aromatic precursors that later influence the flavour of the products through Maillard reactions. Subsequently, the beans are dried (often in the sun) to reduce their moisture to levels below 8%, allowing for stable storage and transport. Throughout this process, the beans acquire a reddish-brown colour, and their taste and aroma undergo modifications. Clearly, the conditions of these processes (fermentation and drying) also impact the final characteristics of cocoa and its derivatives.

Roasting

Cocoa processors begin by roasting the beans. This process enhances Maillard reactions, affecting the taste and aroma of the product. Roasting must occur at not excessively high temperatures (below 120ºC), as higher temperatures intensify “burnt” aromas and lead to the loss of certain volatile components. After roasting, the beans are broken, and the outer shell is removed. Some manufacturers prefer to remove this shell beforehand and roast only the inner part, reducing the microbiological load to a greater extent and slightly altering the obtained aromas.

Milling and conching

After roasting, the inner part of the beans undergoes a grinding process. As the fat content is very high (above 50%), a paste called cocoa liquor is formed, serving as the basis for all cocoa-derived products. The milling process, the equipment used, and its regulation also influence the products obtained, requiring the final particle size to be as fine as possible. However, after the initial milling, the size of solid particles is still too coarse, and the taste of the liquor is excessively bitter.

For chocolate production, cocoa liquor undergoes a process called conching, where the size of solid particles is drastically reduced. During this process, other ingredients and additives, such as sugars, emulsifiers, or dairy products, can be added beforehand. Conching is performed using specific equipment and lasts from several hours to three days, at temperatures slightly above 50ºC but below 90ºC. In addition to reducing the particle size of solid particles, conching lowers the viscosity of the paste and removes part of the present moisture.

If the chocolate is intended for fillings and coatings, a prolonged conching with the smallest possible particle size (10-20 microns) is preferable, as it helps generate a smoother final texture. However, if the chocolate is to be incorporated into cake or cookie formulations, it is not necessary to reduce the particle size as much. This liquor can also be introduced into molds and sold in various solid forms after baking.

Chocolate liquor can go through certain equipment that separates its fat part, through pressure, from its more solid parts. The fat part is known as cocoa butter, has a yellowish colour, and is quite stable, partly due to its saturated fatty acid content. This butter can be added to cocoa liquor before conching to obtain differentiated products. The solid residue is ground and known as cocoa powder.

Therefore, it is possible to obtain chocolate-like products without cocoa butter, replacing this fat with others, for example. The nomenclature of these products depends on the legislation of each country, but in general, products not primarily made with cocoa butter tend not to be labelled as chocolate.

Tempering

Cocoa butter presents a significant advantage for use in coatings due to its melting range. This fat is solid at room temperature, allowing for a solid, brittle, and shiny coating. However, it usually melts at temperatures higher than body temperature, melting in the mouth, creating a refreshing effect (capturing heat from the mouth), and avoiding greasy sensations typical of fats with a higher melting point. Nevertheless, cocoa butter poses a significant problem in how it crystallizes during cooling processes. Cocoa fat can crystallize in six different forms.

When cocoa fat is rapidly cooled, it usually crystallizes in the so-called gamma (γ) form, highly disordered. However, if it is slowly cooled, crystals form in the alpha (α), beta (β), and beta prime (β’) forms. Two other forms exist, but they are minor and seem to be intermediate. The goal is to enhance the beta forms, as they are more stable and produce higher-quality products. Failure to achieve this goal can result in sandy texture (excessively large fat crystals), changes in viscosity (affecting pipeline transport), and more frequent bloom phenomena (whitish spots on the surface) in the final product. Solid chocolate is also less crispy and brittle when cut and less shiny.

To enhance the formation of beta-type crystals, it is possible to “seed” these crystals to serve as nucleation points. However, it is more common to use specific temperature cycles, shown to enhance these types of crystals. This cycle involves melting all crystals at 49ºC, lowering the temperature to 31ºC with constant stirring, and reheating it to 33ºC before application. If we are talking about milk chocolate instead of dark chocolate, the cycle changes slightly, requiring melting at 43ºC, cooling to 28ºC, and reheating to 31ºC. The operation by which chocolate is subjected to this temperature cycle is known as tempering. In the case of chocolate-like products where cocoa fat has been replaced by other fats, tempering is not necessary, as they are not as sensitive to the different types of crystals formed.

Cocoa Powder

Cocoa powder, obtained after removing cocoa butter, typically has a fat content ranging between 10-12%, but in some cases, it can reach 20%. This percentage cannot be reduced with standard pressing processes. Cocoa powder has a strong cocoa flavour. It should be noted that cocoa butter contributes little cocoa flavour, and by removing it, flavours are more concentrated. This powder can be used in various bakery, pastry, confectionery, and biscuit preparations. However, its functionality depends on its fat content, moisture, and particle size. Commercial cocoa powder usually has a fine and uniform particle size, moisture below 5-6%, and a variable fat content, as mentioned earlier. Due to its low moisture content, it has a high water absorption capacity, which must be considered when incorporating it into formulations (additional water may be required) and in its storage (in closed containers and dry places). It is also advisable to store it away from light to minimize the risk of rancidity. If cocoa powder absorbs water during storage, lumps can form, and in extreme cases, microbial contamination can develop.

Dutch Process

Untreated alkaline cocoa powder and chocolate are known as natural and have a slightly acidic pH (5.2-5.8). However, if these products undergo treatment to increase their pH, known as Dutch processing, besides losing acidity, the flavour is softened, bitterness reduced, and the colour darkened, enhancing stability in a solution. This type of cocoa is usually preferred for incorporating into cake or cookie dough, while natural cocoa is more commonly used in fillings or beverages.

The alkalization process can take place at different stages of processing, either at the beginning, on the cocoa cake, or on the cocoa powder. The final result depends on the type of alkali, its concentration, and processing conditions.