INCREASE IN THE SIZE OF ARABICA COFFEE BEANS WITH THE ROASTING PROCESS

Arabica coffee is known for producing the best quality beverages. During its post-harvest processing by wet or dry means, fermentative processes can occur that cause physical and chemical alterations, such as a reduction in sugars and water. During the roasting process, physical and chemical transformations take place in the grain including an increase in volume, which occurs when the pressure inside the bean rises, causing it to expand. The aim of this study was to analyze the size of coffee beans at different roasting times. Self-induced anaerobic fermentation (IAF) of the natural coffee fruit of the Paraiso took place over 72 hours in 200L drums, varying the external temperature, whether or not water was added, and whether or not starter cultures were used. Roasting took place in an electric roaster, at a temperature of 187°-195°C, for approximately 10 minutes, depending on the initial humidity of each sample and the parameters of gas pressure, air flow and speeds were set to maintain the same roasting pattern. The grains were observed at different stages of roasting (time 3, 6 and 9 minutes) and an expansion was noted at each of the times, which was to be expected. According to the literature, depending on the type of coffee, time and degree of roasting, the increase in volume of the beans can more than double. In this study, the average increase in the grain size was 13.05% in 3 min, 14.98% in 6 min and 29.99% in 9 min. In conclusion, the coffee beans after roasting had the expected expansion according to the literature.