alcohol distillation

Balance of Proofs in Distilled Spirits Most spirits sold today are bottled at 80 proof alcohol by volume for taxation reasons and this seems to be a popular consumer preference; however, certain single malt whiskies and aged gins offer greater flavor at higher strength concentrations.

Distillers use hydrometers (gauges) to precisely determine the proof of spirits. A liquid sample is placed into a test jar or parrot, then its reading compared against an associated chart of temperature corrections – the figure on the right of said chart corresponds with its hydrometer reading indicating its true proof level.

But that’s only half the battle; to achieve proof, knowing exactly how much water needs to be added is also essential – which is where tables come into their own.

Weighing is a legally required step for most craft distillers, where empty container weights (tare weights) are subtracted from observed (total) weight to calculate net weight and thus tank content. Tare weights can then be converted to gallonage using TTB’s Gauging Manual.

Proof originates in British naval tradition of allocating daily rations of rum to sailors. When doing this, they would use gunpowder soaked into the liquid as proof that it could ignite. Once this tradition spread, consumer safety and taxation purposes also used this system for other spirits as proof.

Alcohol distillation is one of the key processes involved in producing spirits, and its influence on branding can be immense. From ingredients and packaging to the backstory behind their creation, distillation has the power to differentiate brands from similar offerings on shelves.

Spirits must begin somewhere. Be it fermented washes of grain (whiskey and gin), fruit or potato (gin and vodka), or crude alcohol distilled from oil or natural gas (vodka), the first step is always preparing the base material – sugar-containing substrate that yeast will consume and eventually turn into alcohol. This usually includes milling and mixing grains, macerating fruit or mashing root vegetables for this step of production.

Fermentation, which transforms sugar from the substrate into alcohol and other byproducts, is an integral component of all spirits, from light vodkas to dark whiskeys.

After fermentation, the mixture is then distilled. Distillers separate volatile alcohols with lower boiling points than Ethanol (drinking alcohol) from water using distillation equipment called foreshots or heads; later more desirable ethanol alcohols with higher boiling points called hearts are separated out as well. One skillful distiller knows when and how to switch the flow away from heads toward hearts in order to produce high-quality hearts that last long enough for consumption.

Reducing product purity while decreasing energy requirements through distillation requires controlling both product purity and the reflux ratio, known as reflux ratio. A unique method for producing 100 percent alcohol is currently under development using an organic material such as finely ground cornmeal as an absorbent for water from the ethanol/water vapor – however this requires extensive research and development effort.