How are grains and produce harvested in the field transformed into spirits we pour into our glasses? Distillation is at the core of it all.

Heating liquid mixtures to their boiling points generates vapour which can then be condensed and collected for later separation of desired compounds–in this instance alcohol. The type of still used has an important influence on the final spirit’s flavor and character: from simple pot stills cobbled together from spare parts to massive stills with glittering lights, there are countless ways of creating spirits through similar basic procedures.

Mashing, which can range in complexity depending on the craft distiller, transforms starch compounds in raw materials into sugar that yeast feeds on. By fermenting these sugar molecules into alcohol and carbon dioxide byproducts, alcohol and carbon dioxide are then separated from one another through various steps including evaporation and condensation to purify and concentrate it into its final form.

Craft distillers who take an all-in approach – known as seed to glass– may require more space, expertise, time and money upfront in terms of time spent growing ingredients for mashing and fermenting processes to create their unique styles of spirit. While some producers who are pioneering craft spirits are doing just this with premade neutral spirits from trusted suppliers before using mashing and fermentation processes to craft unique styles. Some newer producers who are making waves within their respective industry and have come to embrace craft spirits themselves are doing things this way as well.

Whisky connoisseurs know that barrel selection plays a huge part in its captivating flavor profile, yet have never really understood why this happens? Well, here is your opportunity to do just that as this article explores all aspects of aging science.

Alcohol distillation involves creating a distillate with high quantities of drinking alcohol as its core, alongside various lower boiling point chemicals like aromatics and esters that have pleasant odours that contribute to quality of the distilled product; yet at certain concentrations can become potentially dangerous. After distillation is complete, its core is separated from watery wash alcohols called heads or tails (known as heads or tails) which may be useful as animal feed sources.

As the ethanol in its heart evaporates, it leaves behind heads and tails which contain water, proteins, carbohydrates, low boiling point alcohols, as well as fertiliser for further processing or spreading on fields as fertiliser. Furthermore, tails contain toxic methanol compounds which can even lead to blindness at very low concentrations.

Methanol molecules cling tightly to ethanol molecules, making separation during distillation challenging. But due to its extremely low boiling point of 64.7@C and ability to dissolve easily in water, it must be removed before selling and consuming spirits such as vodka. To do so, separate liquid in a still, chill it to -80degC and allow the methanol molecules to escape via evaporation.

Distillation is one of the most energy-intensive separation processes used in chemical plants, and separates components by their boiling points in multicomponent mixtures. Distillation has a significant impact on overall energy usage of chemical plants.

Energy requirements of distillation columns depend on both reboiler heat duty (which represents the major energy usage), and condensation heat recovery at the condenser (which has less of an impact). There are various strategies available to reduce energy consumption when distilling, including:

An incorrect feed location on a multicomponent distillation train can drastically increase reflux/boil-up ratio and therefore energy usage. An ideal feed location would be one in which composition of internal liquid traffic (column internal liquid traffic) and feed stream is as similar as possible to prevent large differences between composition gradients between streams.

Distillation energy savings strategies center around optimizing the reboiler or column’s separation performance, such as changing its configuration for multicomponent distillation trains to alter composition or concentration profile of internal liquid traffic or concentration profile; thoughtful use of side draws may further lower energy usage in multicomponent columns.

Distillation column control is key to optimizing overall energy consumption, according to Pete. An ideal system needs to reduce the integral error between actual and desired trajectory of a process without compromising plant robustness or operability – something achieved using advanced PID controllers or model predictive control, but unfortunately these aren’t widely available yet in industrial markets. Companies using SmartProcess control have achieved 40-80% variability reduction, 5-10% throughput increase, 5-10% energy cost savings, less off-spec / rework and improvements in safety/environmental metrics