Theoretical Introduction To Distillation And The Differences To Beer Brewing
Updated: Feb 18, 2022
Disclaimer: Distilling alcohol in Australia is illegal unless you have the appropriate licence. It is also illegal to own a still over 5L in volume without a permit. You can own a still <5L in volume without a permit but you can only distil water, essential oils, biofuels etc.
What is distillation?
Separating the components or substances from a liquid mixture by using selective boiling and condensation.
Distilled Water example
Before we get to distilling
A still does not create alcohol. As we know, yeast does that! Same as in beer, wine and cider.
As brewers, we are used to thinking about what flavours we want to get in our final beer. We think about the malt base depending on what style of beer we want to make. Do we want rich malty flavours? Lighter bready flavours? Chocolate/Coffee flavours? Each of these outcomes will steer you towards certain inputs on the malt side of things.
We can add to these flavours by using hops for bitterness, flavour and aroma. Again, thinking about the style of beer we want to make, will influence our choices for hops, both in terms of variety as well as how much and when we add them to the beer.
The final input we can use to influence flavour is yeast choice and fermentation profile. A pale ale will call for a neutral yeast (i.e. US-05) fermented in its optimum range (18-22C) to produce a very neutral yeast character.
However, a Belgian Wit, or Saison, may call you to choose an estery or phenolic yeast and deliberately stress it to create banana, clove or bubblegum esters/phenolics.
ABV
On top of WHAT grains (fermentables) and yeast we are going to use, we need to decide how MUCH we are going to use. The more fermentables we add, the more sugar there will be to convert into alcohol (and CO2 and a few other things).
Once fermentation has finish, the beer journey is more or less complete (except packaging, secondary fermentation - if using, and conditioning)
Beer Vs Spirits
Beer brewers talk about wort when referring to pre-fermented sugary liquids. Distillers call this same thing a wash. One slight difference between the two terminologies is that the wash is kept post fermentation up until the product is run through the still.
Just like seltzers, many hobby distillers will use sugar or dextrose as their fermentable sugar source and ferment with either bread yeast, turbo yeast or champagne yeast. When dealing with sugar washes (molasses and agave washes are similar in this regard) special care should be taken, as there is nothing in the wash to prevent the pH of the wash dropping too low for the yeast to handle during fermentation. Turbo yeast combats this by using pH buffers as part of its “special mix”. If you are looking to make alcohol at home using these simple sugar methods, you will need to add carbonates to your water in order to buffer the pH change throughout fermentation (unless you are using turbo yeast which contain pH buffers already).
When making a grain based spirit, the mash is very similar to a beer mash. Depending on the recipe there may be a higher percentage of unmalted cereal grains which might call for the use of enzymes in order to convert the starches into fermentable sugars.
Many distillers choose to ferment on the grain which means they leave the grain in the wash during fermentation. This can lead to what beer brewers would classify as an infection. However, this quality can be desirable in distillation as the acids created during fermentation can undergo what is known as esterification when put through the still. Esterification is a reaction which happens between an acid and an alcohol to form an ester which can contribute to fruity or other complex esters in the final spirit.
Distillers of flavour rich product (anything except neutral spirit), like brewers choose yeasts based on the flavour profile they are going for. Many distillers also co-pitch a blend of varieties to get the combination of characteristics just right.
Still Types
Generally speaking, there are two (2) main types of stills; reflux and pot stills.
Reflux stills are designed to make high purity, low flavour spirits (such as vodka)
Pot stills are designed to make high flavour carry over, and the consequence of that is that you get lower purity.
There are other types of still designs, but most of them fall into one of these two categories. Table below gives you an example of some spirits and how they are made.
Spirit | Made from | Additions? | Distillation Method | Ageing? | Comments |
Vodka | Sugar, grains or from any other forms of starch (e.g. potatoes) | NA traditionally, however flavoured vodka is also popular | Reflux | No | Considered a neutral alcohol as it should mainly contain pure ethanol |
Gin | Neutral Alcohol and botanicals | Botanicals added either to the boiler, gin basket (vapour path) or macerated (soaked) | Reflux to create the neutral spirit then a pot or column still to retain flavour | Usually not, but some aged examples are around | Starting with a neutral base spirit, the distiller will add different botanicals to extract the flavour he/she wants. |
Whisky/Whiskey | Malted/Cereal Grains | Flavours come from mixing malt and yeast combinations, fermentation parameters, distillation method/cuts and finally barrels the spirit is aged in | Usually pot still to retain maximum flavour | In Australia, Whisky MUST be aged in wooden containers for at least 2 years. | |
Bourbon | At least 51% corn + Malted/Cereal Grains | Flavours come from mixing malt and yeast combinations, fermentation parameters, distillation method/cuts and finally barrels the spirit is aged in | Usually pot still to retain maximum flavour | In Australia, Bourbon MUST be aged in wooden containers for at least 2 years. | |
Rum | Molasses and other cane sugars | Flavours come from mixing sugar and yeast combinations, fermentation parameters, distillation method/cuts and finally barrels the spirit is aged in | Usually pot still to retain maximum flavour | In Australia, rum MUST be aged in wooden containers for at least 2 years. | White rum is filtered to remove the colour after ageing. Spiced rum is also popular where spices are added. |
Making ‘cuts’
Boiling point of ethanol alcohol 78.2C (at sea level)
Fraction Name / Boiling Point | Description |
Foreshots/Methanol 64.7C* | Poisonous, acetone/nail polish |
Heads <78.2C* | Prickly and burning |
Hearts ~78.2 - ~85C* | Cleanest/purest fraction |
Tails >84C* | Wet dog, cardboard, wet hay |
*Depending on how you are distilling (column choice, wash makeup etc) these temperature points will move around a little. It’s best to make your cuts based on flavour rather than temperatures or volumes.
In a perfect world, the entire volume of the run might look something like this. The different colours represent the main fractions of your distillation run.
Running your still with more power in the boiler increases vapour speed and therefore allows less separation within the column, leading to increased smearing. Smearing refers to different fractions of the distillation turning up in multiple cuts. The image below attempts to show the effect of smearing using colours gradually transitioning from one fraction to the next.
Distillers will adjust the amount of power in their boiler to slow the vapour speed, and therefore product take-off speed down. This allows the distiller to get the cleanest distillate out of their still, leading to a better quality product.
Further learning
If you are interested in distilling and like gin, I would highly recommend the Gin School experience at Earp Distillery, Carrington.
YouTube Channel - Stillit
YouTube Channel - Bearded and Bored
YouTube Channel - Barley and Hops
Books
Still Magic - Marcel Thompson
The Joys of Home Distilling - Rick Morris
Links
Prepared by Andrew Rostas