We investigate a model for the production of ethanol through continuous fermentation. Earlier studies have shown that by using continuous fermentation, rather than other methods such as centrifuges and settling tanks, the productivity can increase markedly. Recently, we showed that in a single tank the biochemical model possess a rich variety array of dynamical behaviour, ranging from oscillations, period-doubling to chaotic behaviour. We use path-following software to gain insights into the behaviour of the system when a cascade of either two or three continuously stirred reactors is used. In particular, we identify design parameters that optimise the productivity of the system in the different reactor configurations.