The Science of Distilling

This is continued from an earlier post that gave a brief overview of the history of distilling.  Vaportini works on the same principles of distillation and I became very interested the subject.  The process takes several key skills, and a good distiller must become adept at all of them.  You must have the scientific acumen, the proper ingredients, the equipment, a good palate, and the experience.

Distillation at its core is separating different liquids through a process of evaporation and condensation.  Alcohol has a lower evaporation temperature than water, therefore when you bring alcohol to the right temperature it turns into vapor while leaving the rest of the liquid (water) behind, still in liquid form.  From there, the vapor is cooled through a long tube and it turns back into liquid, but with concentrated alcohol content.  This is the basis for all modern alcohol distillation.


Whiskey Mash

The right ingredients are a necessity to make your mash.  Mash is a mixture of sugars, starch, and water that is fermented.  This is the same way that wine and beer are made also.  This can be done with fruit and grains most of the time and after a mash is complete it should be around 15-20% alcohol.


Column/Reflux Still


Pot Still

Once a distiller has a mash ready it is time to distiller.  For this, as you can imagine, a still is necessary.  Now, there are 2 commonly used types of stills and they produce different tastes.  There is the pot still and the column/reflux still.  A pot still is a simplistic form that condenses the alcohol vapors that come off the boiling mash.  A reflux still does these multiple distillations in one single go, by having some packing in a column between the condensor & the pot, and allowing some of the vapour to condense and trickle back down through the packing.

Different mixtures of the sugar and starch in your mash will determine the flavor of the alcohol produced.  Directly after distilling the alcohol content will be very high (60-95%) so it will be hard to taste a difference at this stage for the average person.  But, an experienced distiller will note the subtleties in the flavor.  At this point in the process is when you start to have your different kind of spirits.  The different kind of spirits are made by using specific ingredients for the mash, and the aging process.  For example, scotch must be made from barley and aged in Oak barrels for at least 3 years.  Vodka can me made from numerous ingredients, it is not aged and the only flavor that comes through is from impurities in the alcohol.  Bourbon must be made with a 51% grain mix and aged in new charred oak containers.

Most of the master distillers have had a lot of experience and typically it is a profession that is passed down from generation to generation so most have been born into the process.