Distillation Flashcards
A spirit, unlike wine or beer, is not a fermented beverage;
rather it is the product of a distillation of a fermented beverage.
The distillation relies upon a simple premise:
alcohol has a lower boiling point than water. At sea level, ethyl alcohol boils at approximately 173°F (78°C); thus, alcoholic vapors can be separated from liquid water and collected in a still. The separation of two liquids with different boiling points is the principle behind fractional distillation, a technique witnessed and employed for thousands of years.
In a simple pot still,
fermented liquor (the “wash”) is placed into a closed vessel and heat is applied directly to the vessel, vaporizing the ethyl alcohol, a certain amount of water, and congeners—volatile molecules such as esters, other alcohols, and aldehydes, which contribute to the flavor (or off-flavor) of a spirit. These vapors travel up through the vessel and into a condensing coil. The vapors will be cooled, condensed into liquid and collected in a separate vessel. In this simple form, the spirit will be impure. The distiller must take care to discard the foreshots—the first vapors to condense—as these contain congeners such as methanol, a toxic alcohol. The tails are also discarded, as unwanted congeners tend to collect in the distillate residue. The retained spirit will be extremely flavorful; however, some styles of liquor require a cleaner character and will undergo continuous distillation
A continuous still has two columns
(the analyzer and the rectifier) and uses steam, rather than direct heat, to vaporize the alcohol. In this still, the alcohol is condensed in a purer fashion, stripping the liquor of excess congeners and creating a higher-alcohol spirit. While congeners are responsible for impurities, they are also the source of flavor; thus, the continuous still sacrifices distinction for a clean spirit.
Bottled spirits, unlike wine, do not continue to develop.
Many spirits depend only on the base fermented material (and oak) for their final flavor; others are flavored with additives by maceration, percolation, or infusion. Maceration and infusion are similar techniques that involve steeping a flavoring agent in alcohol; maceration is a slower, cold method and infusion is a quicker, hot method. The percolation method resembles coffee brewing, as the base spirit is pumped through the flavoring material. Lower quality flavored spirits may be the simple product of artificial flavor and color additives.
Proof
The ability of gunpowder to combust when doused in the spirit. Used until 1960 in the UK. Today, the alcoholic content of all alcoholic beverages in the EU and the US, whether fermented or distilled, is stated as a percentage of alcohol by volume (abv) at 20°C. American spirits may list a proof on the label—American proof is twice the percentage of alcohol by volume—but are not required by law to do so. The range of abv for liqueurs is generally 15-30%, whereas spirits such as vodka and gin may reach 40-50% abv. The range for whiskey, brandy and rum is much wider, with some cask-strength whiskies—those that are not diluted with water prior to bottling—reaching over 60% abv.
Five things common to all spirit production…
- Selecting raw materials
- Processing the raw materials
- Alcoholic fermentation
- Distillation
- Post distillation operations
In order to be cost effective…
Raw materials need to have a large store of carbohydrates
Selecting the raw materials…
To determine in part the category and style of spirit that is produced
Processing the raw materials….
To produce a sugar solution for alcoholic fermentation
Alcoholic fermentation….
To produce alcohol and congeners
Distillation…..
To concentrate and select alcohols and congeners
Post- distillation operations
To refine or add to a spirits flavour and appearance in readiness for sale. Options include:
- Maturation
- Addition of flavour
- Blending
- Finishing
Plants store carbohydrates in one of three forms
Sugars, starch and inulin
Starch, found in grains and potatoes, and inulin, found in agave….
Are insoluble in water and cannot be consumed into sugars.
Alcoholic fermentation has two important outcomes….
It produces alcohol, but also flavours
Congeners
Compounds responsible for flavours in spirits
Sometime and alcoholic liquid is left to stand so that…..
Extra congeners can form after fermentation
Small batch producers
Ferment in batches
Large scale producers ferment
Using a continuous process of fermentation
There are two ways in which a distiller can control congener production…
Yeast strains and controlling environmental conditions
To control congeners the same yeast strain….
Must be used very time. Different yeast strains produce different congeners and different results
Wild yeast/ ferment is possible in the production of spirits….
But it is extremely rare
Components of an alcoholic beverage….
Alcohols and congeners (and also water)
What is the most abundant alcohol in spirits?
Ethanol
Between water and ethanol…
They typically make up 99% of an alcoholic beverage
Methanol is also an important alcohol….
As are the fusel oils (a group of alcohols that include propanol, butanol and alcohol)
Proof- North America
This is a scale ranging from 0 to 200 degrees. In this system a measure of proof is equal to twice ABV. For example 80 degrees proof is 40% ABV.
