Fermentation is one of the most important steps because it determines how the chocolate will taste. If the beans are under-fermented, little or no aroma is formed, whereas if they are over-fermented, the chocolate is inedible – in the worst case, the beans will develop mould. For the process, the beans are placed in a wooden box together with their own pulp. During the fermentation, part of the cacao mucilage comes off. The sugar and the acidity in the fruit flesh cause the yeast fungus to multiply. In a simplified way, it converts sugar into ethyl alcohol and carbon dioxide. Due to this chemical reaction, the temperature inside the box rises up to 35°C. After about 24 hours, the beans are turned several times – and oxygen is added: The aerobic bacteria convert the alcohol into acetic acid. The temperature rises again by 45 – 50°C and destroys the germ in the cacao bean. After this step, the beans are useless as seeds – but are now suitable for chocolate making. A fermentation normally takes about 7 – 8 days.