A pot still is a type of distillation apparatus or
still
A still is an apparatus used to distill liquid mixtures by heating to selectively boil and then cooling to condense the vapor. A still uses the same concepts as a basic distillation apparatus, but on a much larger scale. Stills have been use ...
used to
distill
Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the heating ...
liquors such as
whisky
Whisky or whiskey is a type of distilled alcoholic beverage made from fermented grain mash. Various grains (which may be malted) are used for different varieties, including barley, corn, rye, and wheat. Whisky is typically aged in wooden c ...
or
brandy
Brandy is a liquor produced by distilling wine. Brandy generally contains 35–60% alcohol by volume (70–120 US proof) and is typically consumed as an after-dinner digestif. Some brandies are aged in wooden casks. Others are coloured with ...
. In modern (post-1850s) practice, they are not used to produce
rectified spirit
Rectified spirit, also known as neutral spirits, rectified alcohol or ethyl alcohol of agricultural origin, is highly concentrated ethanol that has been purified by means of repeated distillation in a process called rectification. In some countri ...
, because they do not separate
congeners from
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...
as effectively as other distillation methods. Pot stills operate on a
batch distillation Batch distillation refers to the use of distillation in batches, meaning that a mixture is distilled to separate it into its component fractions before the distillation still is again charged with more mixture and the process is repeated. This is in ...
basis (as contrasted with
Coffey Coffey may refer to:
__NOTOC__ People
* Coffey (surname)
* Coffey Anderson (born 1978), American country and gospel singer and songwriter
Places
* Coffey, Missouri, a city in Daviess County, Missouri
* Coffey County, Kansas
* Coffey County Airport, ...
or column stills, which operate on a
continuous
Continuity or continuous may refer to:
Mathematics
* Continuity (mathematics), the opposing concept to discreteness; common examples include
** Continuous probability distribution or random variable in probability and statistics
** Continuous ...
basis). Traditionally constructed from
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
, pot stills are made in a range of shapes and sizes depending on the quantity and style of spirit desired.
Spirits distilled in pot stills top out between 60 and 80 percent
alcohol by volume
Alcohol by volume (abbreviated as ABV, abv, or alc/vol) is a standard measure of how much alcohol (ethanol) is contained in a given volume of an alcoholic beverage (expressed as a volume percent). It is defined as the number of millilitres (mL) o ...
(ABV) after multiple distillations. Because of this relatively low level of ABV concentration, spirits produced by a pot still retain more of the flavour from the wash than distillation practices that reach higher ethanol concentrations.
Under European law and various trade agreements,
cognac
Cognac ( , also , ) is a variety of brandy named after the Communes of France, commune of Cognac, France. It is produced in the surrounding wine-growing region in the Departments of France, departments of Charente and Charente-Maritime.
Cog ...
(a protected term for a variety of brandy produced in the region around
Cognac, France
Cognac (; Saintongese: ''Cougnat''; oc, Conhac ) is a commune in the Charente department, southwestern France. Administratively, the commune of Cognac is a subprefecture of the Charente department.
Name
The name is believed to be formed from ...
) and any
Irish
Irish may refer to:
Common meanings
* Someone or something of, from, or related to:
** Ireland, an island situated off the north-western coast of continental Europe
***Éire, Irish language name for the isle
** Northern Ireland, a constituent unit ...
or
Scotch whisky labelled as "pot still whisky" or "
malt whisky" must be distilled using a pot still.
[The Scotch Whisky Regulations 2009](_blank)
''The National Archives'', 2009.
Method of operation
During first distillation, the pot still (or "wash still") is filled about two-thirds full of a fermented liquid (or
wash
WASH (or Watsan, WaSH) is an acronym that stands for "water, sanitation and hygiene". It is used widely by non-governmental organizations and aid agencies in developing countries. The purposes of providing access to WASH services include achievin ...
) with an alcohol content of about 7–12%.
In the case of whiskey distillation, the liquid used is a beer, while in the case of brandy production, it is a
base wine. The pot still is then heated so that the liquid boils.
The liquid being distilled is a mixture of mainly water and alcohol, along with smaller amounts of other by-products of fermentation (called
congeners), such as aldehydes and esters.
At
sea level
Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised g ...
, alcohol (
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...
) has a normal boiling point of while pure water boils at .
As alcohol has a lower boiling point, it is more volatile and evaporates at a higher rate than water. Hence the concentration of alcohol in the vapour phase above the liquid is higher than in the liquid itself.
During distillation, this vapour travels up the ''swan neck'' at the top of the pot still and down the ''lyne arm'', after which it travels through ''the condenser'' (also known as the ''worm''), where it is cooled to yield a
distillate
Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the heat ...
with a higher concentration of alcohol than the original liquid.
After one such stage of distillation, the resulting liquid, called "low wines", has a concentration of about 25–35% alcohol by volume.
These ''low wines'' can be distilled again in a pot still to yield a distillate with a higher concentration of alcohol.
In the case of many
Irish whiskeys, the spirit is distilled for a third time. However, cognac and most
single malt Scotch whiskies are distilled only twice.
A still used for the redistillation of already-distilled products (especially in the United States) is known as a ''doubler'' named after its approximate effect on the level of the distillation purity.
Distillers of around 1800 having sufficient resources to operate both a primary still and a separate doubler would typically use a smaller still for the doubler (typically about half the capacity) than for the first distillation.
[
An alternative way to reach an increased distillation purity without a full second stage of distillation is to put another pot (often a passive pot i.e., without an external heat source) between the pot still and the cooling worm. Such a pot is known as a ''thumper'' named after the sound made by the vapour as it bubbles through a pool of liquid in the thumper.] The distinction between a thumper and a doubler is that a thumper receives its input as a vapour prior to cooling, while the intake of a doubler is an already-condensed liquid.[
During distillation, the initial and final portions of spirit which condense (with the first portions termed the ''foreshots'' and ''heads'' and the final parts called the ''tails'' and ''feints'') may be captured separately from that in the centre or "heart" of the distillation and may be discarded. This is because these portions of the distillate may contain high concentrations of congeners (which it may be desirable to keep out of the final distillate for reasons of style, taste and toxicity). For example, the presence of ]pectin
Pectin ( grc, πηκτικός ': "congealed" and "curdled") is a heteropolysaccharide, a structural acid contained in the primary lamella, in the middle lamella, and in the cell walls of terrestrial plants. The principal, chemical component of ...
in the wash (e.g., due to using a mash made from fruit) may result in the production of methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...
(a.k.a. wood alcohol), which has a lower boiling point than ethanol and thus would be more concentrated in the foreshots. Methanol is toxic and at sufficient concentrations, it can cause blindness and fatal kidney failure. It is especially important to discard the initial foreshots, while a small amount of the near-centre heads and tails are often included in the final product for their effect on the flavour.
History
The modern pot still is a descendant of the alembic, an earlier distillation
Distillation, or classical distillation, is the process of separation process, separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distilla ...
device.
The largest pot still ever used was in the Old Midleton Distillery
The Jameson Experience, Midleton, (also known as the Old Midleton Distillery) is an Irish whiskey museum and visitor centre located in the Old Midleton Distillery in Midleton, County Cork, Republic of Ireland, Ireland. Set over 15 acres, since ...
, County Cork
County Cork ( ga, Contae Chorcaí) is the largest and the southernmost county of Ireland, named after the city of Cork, the state's second-largest city. It is in the province of Munster and the Southern Region. Its largest market towns are ...
, Ireland. Constructed in 1825, it had a capacity of and is no longer in use. As of 2014 the largest pot stills in use are in the neighbouring New Midleton Distillery
The Midleton distilleries complex is situated in Midleton, County Cork, Ireland. It is owned by Irish Distillers, a subsidiary of Pernod Ricard. Located alongside is the Old Midleton Distillery, which was established in the early 17th century a ...
, County Cork, Ireland, and have a capacity of .
Components of a traditional pot still:
* Pot – where the wash is heated
* Swan Neck – where the vapours rise and reflux
* Lyne Arm – transfers the vapour to the condenser
* Condenser or worm – cools the vapour to yield distillate
File:Cognac pot still - 20091205.jpg, A cognac
Cognac ( , also , ) is a variety of brandy named after the Communes of France, commune of Cognac, France. It is produced in the surrounding wine-growing region in the Departments of France, departments of Charente and Charente-Maritime.
Cog ...
pot still
Image:Whisky safe DSC05276.JPG, A spirit safe
A spirit safe or intermediate spirit receiver is an enclosed device used in the distillation of Scotch whisky. The distillate from the still
A still is an apparatus used to distill liquid mixtures by heating to selectively boil and then ...
(i.e. padlocked apparatus at the end of the pot still enabling the distiller to cut off the "heads" and "tails" of distillation; it is padlocked for excise
file:Lincoln Beer Stamp 1871.JPG, upright=1.2, 1871 U.S. Revenue stamp for 1/6 barrel of beer. Brewers would receive the stamp sheets, cut them into individual stamps, cancel them, and paste them over the Bunghole, bung of the beer barrel so when ...
accounting reasons)
See also
* Alembic
* Batch distillation Batch distillation refers to the use of distillation in batches, meaning that a mixture is distilled to separate it into its component fractions before the distillation still is again charged with more mixture and the process is repeated. This is in ...
* Column still
A column still, also called a continuous still, patent still or Coffey still is a variety of still consisting of two columns. Column stills can produce rectified spirit (95% ABV).
Description
The first column (called the analyzer) in a column ...
* Single pot still whiskey
Single pot still whiskey is a style of Irish whiskey made by a single distillery from a mixed mash of malted and unmalted barley distilled in a pot still. Somewhat similar to single malt whiskey, the style was defined by its inclusion of unmalte ...
* Poitín
Poitín (), anglicized as poteen () or potcheen, is a traditional Irish distilled beverage (40–90% ABV). Former common names for Poitín were "Irish moonshine" and "mountain dew". It was traditionally distilled in a small pot still and the ...
* Moonshine
Moonshine is high-proof liquor that is usually produced illegally. The name was derived from a tradition of creating the alcohol during the nighttime, thereby avoiding detection. In the first decades of the 21st century, commercial dist ...
References
External links
{{Commons category, Pot stills
The Scottish Pot Stills: The Centrepieces of Every Distillery
at Whisky.com
pot stills
at a-c-e.uk
Distillation
pt:Alambique