During fully aerobic continuous growth of Saccharomyces cerevisiae on fructose- and sucrose-limited cultures, there exists the possibility of a number of distinct steady states at higher dilution rates. It is thus postulated that a number of discrete "states" exist for yeast cells under constant environmental conditions and that the particular "state" obtained is a function of the time spent under these conditions (adaptation) and the manner in which the steady state was approached. These observations are significant since they provide an insight into the large range of responses possible by yeasts in continuous cultures and may help to explain why unified views of sugar utilisation by yeasts have been so elusive.