A pot still is a type of distillation apparatus or still used to distill liquors such as whisky or brandy. In modern (post-1850s) practice, they are not used to produce rectified spirit, because they do not separate congeners from ethanol as effectively as other distillation methods. Pot stills operate on a batch distillation basis (as contrasted with Coffey or column stills, which operate on a continuous basis). Traditionally constructed from copper, 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 (ABV) after multiple distillations.[ citation needed ] 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 (a protected term for a variety of brandy produced in the region around Cognac, France) and any Irish or Scotch whisky labelled as "pot still whisky" or "malt whisky" must be distilled using a pot still. [1] [2] [3]
During first distillation, the pot still (or "wash still") is filled about two-thirds full of a fermented liquid (or wash) with an alcohol content of about 7–12%. [4] [5] [6] 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. [5] At sea level, alcohol (ethanol) has a normal boiling point of 78.4 °C (173.1 °F) while pure water boils at 100 °C (212 °F). [7] 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 with a higher concentration of alcohol than the original liquid. [5] 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. [6] 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. [8] [9] 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. [9]
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. [10] 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. [8] [10]
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 in the wash (e.g., due to using a mash made from fruit) may result in the production of methanol (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. [11] [12]
The modern pot still is a descendant of the alembic, an earlier distillation device.
The largest pot still ever used was in the Old Midleton Distillery, County Cork, Ireland. [13] [14] Constructed in 1825, it had a capacity of 143,740 litres (31,618 imp gal) and is no longer in use. As of 2014 the largest pot stills in use are in the neighbouring New Midleton Distillery, County Cork, Ireland, and have a capacity of 75,000 L (16,000 imp gal). [15]
Components of a traditional pot still: [7]
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 of solid materials to produce gaseous products ; this may involve chemical changes such as destructive distillation or cracking. Distillation may result in essentially complete separation, or it may be a partial separation that increases the concentration of selected components; in either case, the process exploits differences in the relative volatility of the mixture's components. In industrial applications, distillation is a unit operation of practically universal importance, but is a physical separation process, not a chemical reaction. An installation used for distillation, especially of distilled beverages, is a distillery. Distillation includes the following applications:
Whisky or whiskey is a type of liquor made from fermented grain mash. Various grains are used for different varieties, including barley, corn, rye, and wheat. Whisky is typically aged in wooden casks, which are typically made of charred white oak. Uncharred white oak casks previously used for the aging of port, rum or sherry are also sometimes used.
Brandy is a liquor produced by distilling wine. Brandy generally contains 35–60% alcohol by volume and is typically consumed as an after-dinner digestif. Some brandies are aged in wooden casks. Others are coloured with caramel colouring to imitate the effect of ageing, and some are produced using a combination of ageing and colouring. Varieties of wine brandy can be found across the winemaking world. Among the most renowned are Cognac and Armagnac from south-western France.
An azeotrope or a constant heating point mixture is a mixture of two or more components in fluidic states whose proportions cannot be altered or changed by simple distillation. This happens because when an azeotrope is boiled, the vapour has the same proportions of constituents as the unboiled mixture. Azeotropic mixture behavior is important for fluid separation processes.
Moonshine is high-proof liquor, generally whiskey, traditionally made, or at least distributed, illegally. Its clandestine distribution is known as bootlegging. 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 distilleries have adopted the term for its outlaw cachet and begun producing their own legally sanctioned, novelty "moonshine," including many flavored varieties, that in some sense continue its tradition, generally having a similar method and/or location of production.
Irish whiskey is whiskey made on the island of Ireland. The word 'whiskey' comes from the Irish uisce beatha, meaning water of life. Irish whiskey was once the most popular spirit in the world, though a long period of decline from the late 19th century onwards greatly damaged the industry, so much so that although Ireland boasted at least 28 distilleries in the 1890s, by 1966 this number had fallen to just two, and by 1972 the remaining distilleries, Bushmills Distillery and Old Midleton Distillery, were owned by just one company, Irish Distillers.
Single malt whisky is malt whisky from a single distillery.
A blended whiskey is the product of blending different types of whiskeys and sometimes also neutral spirits, colorings, and flavorings. It is generally the product of mixing one or more higher-quality straight or single malt whiskey with less expensive spirits and other ingredients. This typically allows for a lower priced finished product, although expensive "premium" varieties also exist.
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 used to produce perfume and medicine, water for injection (WFI) for pharmaceutical use, generally to separate and purify different chemicals, and to produce distilled beverages containing ethanol.
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.
Liquor is an alcoholic drink produced by the distillation of grains, fruits, vegetables, or sugar that have already gone through alcoholic fermentation. Other terms for liquor include: spirit, distilled beverage, spirituous liquor or hard liquor. The distillation process concentrates the liquid to increase its alcohol by volume. As liquors contain significantly more alcohol (ethanol) than other alcoholic drinks, they are considered "harder." In North America, the term hard liquor is sometimes used to distinguish distilled alcoholic drinks from non-distilled ones, whereas the term spirits is more commonly used in the UK. Some examples of liquors include vodka, rum, gin, and tequila. Liquors are often aged in barrels, such as for the production of brandy and whiskey, or are infused with flavorings to form flavored liquors, such as absinthe.
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 countries, denatured alcohol or denatured rectified spirit may commonly be available as "rectified spirit", because in some countries the retail of rectified alcohol in its non-denatured form is prohibited.
Cooley Distillery is an Irish whiskey distillery on the Cooley Peninsula in County Louth, Ireland. The distillery was converted in 1987 from an older potato alcohol plant by entrepreneur John Teeling. On 16 December 2011 Beam Inc. announced plans to purchase Cooley for around US$95 million (€71 million); the deal closed a month later, and the distillery now belongs to Beam Suntory since Suntory bought Beam in 2014.
Aeneas Coffey (1780–1839) was an Irish inventor and distiller.
Redbreast is a brand of single pot still Irish Whiskey produced by Irish Distillers. It was originally bottled by Gilbey's, a Dublin spirits merchant using distillate sourced from Jameson's Bow Street Distillery. In the 1980s, the brand was purchased by Irish Distillers, the producer of Jameson. It is the largest selling single pot still Irish whiskey in the world.
This glossary of winemaking terms lists some of terms and definitions involved in making wine, fruit wine, and mead.
Straight whiskey, as defined in United States law, is whiskey that is distilled from a fermented cereal grain mash to a concentration not exceeding 80% alcohol by volume (abv) and aged in new charred oak barrels for at least two years at a concentration not exceeding 62.5% at the start of the aging process. Domestic sales of straight whiskey surpassed 27 million 9-liter cases in 2021.
The Chalvignac Group is an international industrial company. Its headquarters are in Jarnac-Champagne, Charente-Maritime, France. It is a global specialist in distillation processes. This group proposed agricultural and wine-growing trailers, stainless steel and fiber tanks, and offers retail winery equipment. Created in the early 20th century, the main company Chalvignac became the center of the Nov-Tech group in 1984, later renamed as the Chalvignac Group.
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 unmalted raw barley in the mash in addition to malt. However, small amounts of raw oats or wheat may have been used at times. This unmalted component is said to give the pot still whiskey a "spicier bristle" and "thicker texture" than the otherwise similar malt whiskeys. If the whiskey is not distilled completely on the site of a single distillery, then it may be termed pot still whiskey but not single pot still whiskey.
Here, I believe, is the largest still in the world—certainly the largest in Ireland.