I don't know how the balance broke down during WW2, but synthesis of ethanol from ethylene in more recent times is economically competitive with fermentation.

I don't know how the balance broke down during WW2, but synthesis of ethanol from ethylene in more recent times is economically competitive with fermentation. So for instance, fermentation of sugarcane is easily cheaper in Brazil, but in America most industrial ethanol came from synthesis until corn subsidies were introduced in the 80s which made fermentation cheaper than synthesis.