Heat treatment generally used to determine the final texture and aroma of chocolate. It consists of using granite rollers to mix and cut the chocolate in order to give it a better flavor and smoothness. Likewise, it allows the improvement of the flavor profile and the reduction of free volatile acids in cocoa. Generally, this process is carried out continuously for three days to ensure good flavor development, although in some processes it can take up to 24 hours.
It is a process where an alkali is used to treat cocoa products (nib, cocoa liquor or powder). The main alkalizing agents used are: sodium or potassium hydroxide, carbonate or bicarbonate; oxide or sodium carbonate. This process is necessary because, after fermentation, cocoa has a low pH (4.7 – 5.5), a result of acetic acid production. Alkalization neutralizes the pH until reaching values of 6.3 – 6.8.
This process confers changes in the color and flavor of the chocolate. Regarding color, the change occurs from dark brown to a reddish or black tone. The taste is generally less bitter.
The change in flavor is produced by the effect of alkalization on pH, which also has an influence on the Maillard reaction induced in roasting and which influences the flavor. Alkalization must be carried out at temperatures between 75 – 100 °C. This process is also used to increase the solubility of cocoa powder used in beverages.
In this processing stage, the characteristic aromas and flavors of cocoa are developed, which are formed from the precursors that have been developed during fermentation and drying. Roasting must be carefully controlled to ensure proper development of the chocolate flavor.
This process can be applied in three ways: whole bean roasting, nib roasting or cocoa liquor roasting. Roasting parameters depend on the variety of cocoa and the specifications of the desired flavors.
The roasting time and temperature should be maintained from 5 to 120 minutes at temperatures between 110 to 160 °C. Over-roasting the beans confers negative results on the characteristics of the chocolate.
After fermentation, the grains have a moisture content of 55%. For storage and subsequent processing, they must be dried until reaching 6 – 8% humidity. During this process, the oxidative reactions of fermentation continue to take place. The most commonly used drying technique is sunlight, because it induces the development of more pronounced flavors in the chocolate. In this case, it should dry approximately between 12 and 20 days, until the ideal humidity percentage is reached.
In regions where the presence of sunlight is irregular, mechanical dryers at 60 – 70 °C are used. In general, the weight loss due to drying is two-thirds of the weight of fresh beans.
It is one of the post-harvest processes that most affects the quality of the products obtained from cocoa. During fermentation, the pulp is degraded by the action of microorganisms, which causes the temperature to rise, the production of ethanol, lactic acid and acetic acid. This process results in the formation of chocolate flavor and aroma precursors, which will develop during the roasting process. Completely fermented beans have a dark brown color.
Without fermentation, cocoa does not develop the desired flavor characteristics during roasting.
There are different fermentation methods, the most common being: wooden crates, rumas or piles and in bags, either jute or polypropylene; However, the best results in the quality of the final product are obtained in wooden crates.
The number of days of fermentation cannot be generalized, it depends on the genetic material, the fermentation method and the quantity to be fermented. Generally the Creole type needs 3 to 4 days; The Trinidadian type requires between 5 to 6 days and the foreign types need 5 to 8 days. It is also important to establish the relationship with the other environmental factors that characterize each producing area.
An indicator of satisfactory fermentation is the presence of a peripheral ring of brown color, indicating that the cocoa should begin to be spread for drying.
Furthermore, when a cross section of the grain is made, a characteristic cracking of the fermented grain is observed and it has a chocolate flavor.
