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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).
The first column (called the analyzer) in a column still has steam rising and wash descending through several levels. [1] The second column (called the rectifier) carries the alcohol from the wash, [2] where it circulates until it can condense at the required strength.
A column still is an example of a fractional distillation, in that it yields a narrow fraction of the distillable components. This technique is frequently employed in chemical synthesis; in this case, the component of the still responsible for the separation is a fractionating column.
A continuous still can, as its name suggests, sustain a constant process of distillation. This, along with the ability to produce a higher concentration of alcohol in the final distillate, is its main advantage over a pot still, which can only work in batches. Continuous stills are charged with preheated feed liquor at some point in the column. Heat (usually in the form of steam) is supplied to the base of the column. Stripped (approximately alcohol-free) liquid is drawn off at the base, while alcoholic spirits are condensed after migrating to the top of the column.
Column stills are frequently used in the production of grain whisky and are the most commonly used type of still in the production of bourbon and other American whiskeys. Distillation by column still is the traditional method for production of Armagnac, although distillation by pot still is allowed. The use of column stills for the distillation of Cognac is forbidden, although they may be used for other types of brandy, likewise malt Scotch Whiskies must be distilled in a pot still. Distillation by column stills is permitted for Calvados AOC and Calvados Domfrontais. Calvados Pays d'Auge AOC is required to be distilled by pot still.
Column stills behave like a series of single pot stills, formed in a long vertical tube. The tube is filled with either porous packing or bubble plates. The rising vapour, which is low in alcohol, starts to condense in the cooler, higher level of the column. The temperature of each successively higher stage is slightly lower than the previous stage, so the vapour in equilibrium with the liquid at each stage is progressively more enriched with alcohol. Whereas a single pot still charged with wine might yield a vapour enriched to 40–50% alcohol, a column still can achieve a vapour alcohol content of 96%; an azeotropic mixture of alcohol and water. Further enrichment is only possible by absorbing the remaining water using other means, such as hydrophilic chemicals or azeotropic distillation, or a column of 3A molecular sieves, like 3A zeolite. [3] [4]
In the early 1800s, a number of different scientists, engineers, and businessmen contributed to the development of a variety of different continuous distillation apparatuses. Several of these early developers were French, spurred on by a prize offered by Napoleon to improve sugar beet development and fermentation, in an effort to reduce reliance on British imports. [5] These early French stills were suited to the production of wine, but deficient in the processing of the residual solids found in whiskey mashes. [6] These French designs were further developed and improved upon by a number of Irish, British, and German contributors, to allow for use in the distillation of whiskey and other liquids. [5] The column still is also called " la Colonne Belge" or the Belgian Column because it was first introduced and used for commercial purposes in Flanders, Belgium in 1828. Notable contributors included:
In 1805, Jean‐Édouard Adam developed a discontinuous fractional distillation apparatus. [5]
In 1806, Bérard developed a device to allow for partial condensation [5]
The work of Adam and Bérard, focused on two key principles: [5]
In 1813, Jean‐Baptiste Cellier‐Blumenthal (1768-1840), built upon and combined these ideas, and patented the first continuously operating distillation column. [5] This still had a pot still type-kettle, but replaced the traditional lyne arm and cooling worm with a vertical column of perforated plates. [7] Although many of the details of Cellier-Blumenthal's column were improved upon in later years, the general concept was to provide the basis for future column still designs. [5] In 1820, he moved to Koekelberg in Brussels, Belgium where he did the first experiments with his column still. The Belgians began distilling with his design soon after as they wanted to innovate in their distilleries.
In 1817, Heinrich Pistorius, a German, patented a still for the distillation of alcohol from potato mash. [5] The Pistorius still produced spirit with an alcohol content of about 60-80%, and was widely used across Germany until the 1870s. [5]
Sir Anthony Perrier (1770–1845) was operator of the Spring Lane distillery (Glen distillery) in Cork, Ireland from 1806. In 1822, he patented one of Europe's first continuous whiskey stills. The still included a labyrinth of partitions, which allowed the wash to flow gradually and continuously over the heat, with increased contact between the vapour and liquid phases of the distillate. In addition, the still contained "baffles", similar to modern bubble trays. [5] This meant small portions of fermented "wash" received the greatest amount of heat, thereby increasing the amount of potable alcohol that was collected. [8]
In 1823, Jean-Jacques St. Marc, a French veterinary surgeon attached to Napoleon's personal staff, moved to England where he sought investors in his "Patent Distillery Company", which was to distill potato brandy. The company erected a distillery at Vauxhall, called the Belmont Distillery, but it proved unsuccessful. [9] During which time, St. Marc worked on developing a continuous distillation apparatus. In 1827 he was granted a patent, and moved back to France. [10] The still was later used successfully in England, Ireland, and the West Indies. [10] [11]
In 1828, Scotsman, Robert Stein, patented a continuous still that fed the "wash" through a series of interconnected pots. Piston strokes were used to vapourise the wash and feed it into a horizontal cylinder which was divided into a series of compartments using cloth. [6] [12] The Stein still offered improved fuel efficiency compared with the traditional pot still and was the first continuous still to be employed commercially in Scotland, finding use at the Kirkliston (1828), Cameron Bridge (1830), Yoker (1845), and Glenochil (1845) distilleries. [6] However, as the still did not allow for siphoning off of the pungent fusel oils, the spirit produced was not highly rectified, and still needed to be stopped frequently for cleaning. [6]
In 1830, Irishman Aeneas Coffey patented the two-column, continuous distillation apparatus which bears his name, versions of which are now ubiquitous across the distilling industries. [7] The still allowed for the production of alcoholic spirit with an ethanol content of greater than 90%, though modern versions can achieve about 95%. [7]
Educated at Dublin's Trinity College, Coffey had ample opportunities to observe all manner of still designs having worked as a distillery excise tax collector for a quarter of a century.
Coffey's early designs, based on modifications to the Cellier-Blumenthal still, were unsuccessful. [7] Being made of iron, they were attacked by the acids in the hot distillate, resulting in a poor spirit. [7] However, his final design, which incorporated design elements from Perrier, Fournier, and Saint Marc, was to prove successful. [6]
In his patent application, Coffey claimed that his design made three new improvements over previous designs: [13]
In addition, the design introduced perforated trays as sieve structures for vapour liquid contact. [5]
This new continuous distillation method produced whisky much more efficiently than the traditional pot stills, [14] without the need for cleaning after each batch was made. [15]
As the reciprocating steam engines of the time were unable to feed the still with the necessary high temperature/pressure steam, it took some time for the Coffey still to dominate the industry. [6] However, with technological improvements, most notably the introduction of steam regulators in 1852, the Coffey still found widespread use in alcohol production across Europe and the Americas. [6] Although, notably, it found resistance within Irish whiskey industry, then the dominant force in global whiskey production, who considered the high-strength spirit, to be inferior in taste profile to lower strength pot still distillate. [7]
Within five years of receiving his patent, Coffey had enough orders to warrant the establishment of Aeneas Coffey & Sons in London, a company that remains in operation today under the name John Dore & Co Limited. He closed Dock Distillery four years later and devoted all of his time to building and installing stills in distilleries owned by others.
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.
Moonshine is high-proof liquor, generally whiskey, traditionally made or 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.
Single malt Scotch refers to single malt whisky made in Scotland. To qualify for this category, a whisky must have been distilled at a single distillery using a pot still distillation process and made from a mash of malted barley. Therefore, a single malt means that the whisky has not been blended elsewhere with whisky from other distilleries. As with any Scotch whisky, a single malt Scotch must be distilled in Scotland and matured in oak casks in Scotland for at least three years, although most single malts are matured longer.
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 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. Traditionally constructed from copper, pot stills are made in a range of shapes and sizes depending on the quantity and style of spirit desired.
Grain whisky normally refers to any whisky made, at least in part, from grains other than malted barley. Frequently used grains include maize, wheat, and rye. Grain whiskies usually contain some malted barley to provide enzymes needed for mashing and are required to include it if they are produced in Ireland or Scotland. Whisky made only from malted barley is generally called "malt whisky" rather than grain whisky. Most American and Canadian whiskies are grain whiskies.
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.
Springbank distillery is a family-owned single malt whisky distillery on the Kintyre Peninsula in western Scotland.
Malt whisky is whisky made from a fermented mash consisting of malted barley. If the product is made exclusively at a single distillery, it is typically called a single malt whisky. Although malt whisky can be made using other malted grains besides barley, those types are not called malt whisky without specifying the grain, such as rye malt whisky or buckwheat malt whisky.
Cooley Distillery is an Irish whiskey distillery on the Cooley Peninsula in County Louth, Ireland founded in 1987 and owned by Beam Suntory.
Aeneas Coffey (1780–1839) was an Irish inventor and distiller.
Downslope Distilling is a craft beverage distillery in Centennial, Colorado, United States.
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 is 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.
The Green Distillery was an Irish whiskey distillery which was established in Cork City, Ireland in 1796. In 1867, the distillery was purchased by the Cork Distilleries Company (CDC), in an amalgamation of five Cork distilleries. Production of whiskey at the distillery likely ceased soon afters its acquisition by the CDC. However, the distillery is known to have remained in use a bonded store by the Cork Distilleries Company for several years thereafter. In the mid-twentieth century, the distillery resumed operations as a gin distillery for a period of time, however, it has since been almost completely demolished.
The following outline is provided as an overview of and topical guide to whisky:
