Microbiologist Nancy Nichols and biochemical engineer Bruce Dien add yeast to a bioreactor to begin ethanol fermentation. Bt and non-Bt corn hybrids were compared for ethanol yields. Photo by Scott Bauer.
Fermentation - Beans are fermented naturally, either on the ground itself or in crates, depending on the country. Fermentation stimulates the chocolate flavour precursors through its two-stage process: - The beans are covered with banana leaves: resulting in ethanol fermentation, a process without oxygen; - Then the beans are stirred resulting in acetic fermentation, a process using oxygen.