Distillation:
Distillation is the process that turns the fermented mash with very low alcohol percent into the sprits that we are trying to get. There are three main devices that can be used to distill our fermented mash. The pot still, continuous still, and the rectifying still are what most professional brewers use to mass-produce their liquors.
Pot Still
The pot still is usually composed in series where the vapor produced is redirected and introduced into another pot still. if the vapor is below a specific alcohol content it will be transferred to a pot still in series with the first one. Pot Stills were used for making whiskey but they took up too much space for large production scale. For larger production, a continuous still is recommended.
Continous Still
The continuous still is very similar to the pot still, the continuous still is essentially pot stills stacked on top of one another. The distillation is very similar to how the pot still treats alcohol vapor. The vapor moves up the tall column and moves between different plates, where each plate has a specific alcohol composition, very much like a distillation column. Plates can be added or removed to control the specific concentration of alcohol obtained from the top of the column.
Rectifying Still
A rectifying still is much different from the pot or continuous still instead of multiple series this system uses the concept from continuous stills and refeeds some of the distillate products back into the still known as the “reflux” this helps repurify the alcohol and takes out many of the volatile products that can add flavor. Reflux helps in purifying the alcohol but has drawbacks that can take out the flavor of your spirit.
If you only wanted to experiment with the idea of brewing you could essentially make your own still at home using old pots, or purchase a chemistry distillation kit online. This helps provide a basic idea on how distillation works.
Distillation Process
Now that we have talked about different distillation devices we should discuss how to add the fermented mash and what to watch. Boiling points are good to know, these values will give a rough estimate on what compounds are going to be coming out of the distillation column. For whatever still that you decide to use, the mash is added and heat is applied to the fermented mash. Once the temperature reaches a constant, the most likely component that will be coming our of the distillation apparatus will initially be methanol. Don’t save any of this product, this can cause blindness and alcohol poisoning if consumed. A good rule of thumb is to toss out the first 50ml of distillate to ensure that no methanol is in the products.
The temperature will increase again once all the methanol has evaporated to about 75 C which is the boiling point of ethanol. The distillate coming out will be primarily ethanol which is what we want. This section of the distillate is commonly known as the hearts and is the main section the distillate we want to collect, when the temperature increased again that will indicate vaporization of other unwanted compounds so its best to collect the hearts and throw away the rest of the distillate. It’s difficult to collect the hearts of the distillate, you have to run a mash multiple times and through your still to get efficient at collecting the hearts. Other parts of the distillate are referred to as the heads and tails. The heads contain some other volatile compounds that might add to the flavor of the spirit and will have boiling point between the methanol boiling point and ethanol. Usually, the tails are thrown out since they mostly contain higher weight compounds that might add to the flavor of the spirit but arent usually collected for flavor enhancement.
Finally, the distillate is collected and there will still be some compounds carried over that are unwanted in your spirit. We have to clean it out by using activated carbon filters. The activated carbon will pull many of the larger unwanted molecules out of the liquid and help purify the liquor. Many of the molecules that help with flavoring will remain intact with the solution the main purpose is to purify the distillate collected.
We have a pure spirit that should be diluted. have to dilute it down to the desired alcohol concentration using water. This can be measured using an alcohol hydrometer which measures the density of the liquid in the corresponding percentage of alcohol that’s in the solution simply by placing it in the solution and reading the percentage the liquid goes up to. Once the liquor is brought to the desired percentage it’s ready to be aged, but some alcohols arent aged like vodka and some rum.