Please visit Part 1 here if you haven’t already, about sugar cane.
Now we have the raw materials we can move onto the fermentation stage of production. It is from this point where huge amount of variation occur from distillery to distillery. The two extremes of the fermentation process vary from “natural fermentation” to laboratory conditions. Natural fermentation occurs in large open vats where the yeast in the environment ferments the sugars. It can be quite inefficient and unpredictable. Laboratory conditions include specific yeast cultures which are purchased by distilleries as well as precautions to minimise environmental affects.
The addition of this yeast (and to a lesser extent, water) is what converts the available sucrose into alcohol. The time is takes can last from just a few hours to a few weeks and also depends on the yeast that is added to the raw materials in this process. Once this has been completed and there is almost no sugar left, the distillation process can begin.