Distillation Processes That Go Behind the Making of Spirits All spirits are manufactured using two major procedures - fermentation and distillation. Let us learn how these procedures work first and then move on to why distillation columns are most widely used. Fermentation: In every Ethanol industry, Fermentation is used to create alcohol while distillation is used to isolate it from the mix. In order for fermentation to take place, you need a liquefied form of agricultural raw material such as barley, rye or sugarcane that contains natural sugar. This raw material used in Bioethanol production, is first ground into a coarse meal to break down the protective hull covering and converted into starch. The starch is then converted to sugar, mixed with pure water and cooked until it forms a liquid. Yeast is then added to this liquid mix called mash. Yeast is a bacteria that breaks down the sugar to create alcohol and CO2. As the yeast starts creating more alcohol and CO2, they are left with less sugar to feed on. After a certain point, the alcoholic environment becomes rather toxic for the yeast and they can no longer continue fermentation. This is where the next step of distillation comes. The production of alcohol can be optimized with respect to the utilization of biomass as an energy source using Bioenergy plant. Distillation: At its principle, distilling is a process whereby we physically separate alcohol from water using evaporation and condensation. Since alcohol has a lower boiling point than water, alcohol gets evaporated and collected into a tube which is then condensed back into liquid form by forcing cold temperature on it. Till date, there have been only 2 methods of distillation: 1. Pot Distilling 2. Column Distilling Pot Distillation: Here, you put a batch of fermented liquid into a copper pot. The pot is then sealed and heated. As the fermented liquid boils, the alcohol, having a lower boiling point than water, starts evaporating first. The vapor rises to the head of the pot still and is diverted to the arm
which leads to a coil. This coil is submerged in cool water which helps condense the alcohol and convert it into a liquid form that runs out of the coil and is collected into a vessel. The vapor that rises though is not 100% alcohol and comprises of congeners and other compounds that influence the taste, smell and texture of alcohol. Pot distillers are not very efficient as compared to distillation columns as they allow only one batch of spirit at a time and needs to be emptied out and cleaned up before the next batch can begin. Column Distillation: A column still can be as high as several stories. It has partitions, or perforated plates, that set up chambers within the still. The mash in the still is heated from the bottom. This could be done by pumping steam at the bottom of the still and letting it rise. The steam is regulated to reach a temperature perfect to separate alcohol from the mix and leave undesired compounds behind as it rises up through the column. The alcohol that rises up is not without its share of congeners though. These elements are removed using timing & temperature control. Column distilling requires no cleaning between the batches. The availability of several columns for alcohol vapors to flow seamlessly allows for efficient and repeated distilling. Column stills can distill proofs as high as the 190s, or 95% ABV. Bourbon, brandy, and other spirits, though, are not generally distilled to such high proofs.