The modern pot still is a descendant of the alembic, an earlier distillation device. It doesn’t separate congeners from ethanol as effectively as other distillation methods so after several distillations the resulting spirit has a strength of 60..80 % ABV, while retaining more aroma.
The product’s flavour profile is more complex than that of a continuously distilled spirits of the same strength. In turn, copper reacts with sulfur compounds and resulting in a smoother, more refined drink.
All this allows congeners to be used to create complex, aromatic and heavier-bodied spirits like whiskey. The variety of taste opens up scop for creative distillers, allowing them to make unique spirits and offer a premium, artisanal drinks.
The unit is made from 99.85% pure copper. Despite individual differences in design and size, most stills have the general technical features necessary for the distillation process.
Boiler (“pot”) is technically adapted to the heating system. The shape of the still’s top has a significant impact on evaporation, steam flow and condensation.
The shape of the head (onion, boil ball, lantern etc) affects reflux and contact with copper. A cone connector (swan neck) , curved piece adaptor and lyne arm direct the vapors into the condenser and control the reflux: taller / narrower “neck” with lyne arm upward angle allows for a lighter spirit thanks to downward pushes fusel oils.
Use a worm tubes condenser for heavier style whisky or make the purest version with a shell and tube condenser. This influence the character of the distillate, as increased copper contact and control of water temperature produce results in a lighter, less complex crude spirit.
The finished distillate is then sent to a spirit safe, where the alcohol value is measured and the further distillation process is controlled.
The pot still is one of the oldest and most traditional methods of whisky distillation. It’s mainly used in distilleries in Scotland and Ireland. The combination of copper, heat input and the master distiller gives pot still whisky depth and individuality.
Fill the still with fermented mash with an alcohol content of around 7-12%. Heat (steam or direct fire). The liquid gradually evaporates; the resulting vapors are continuously removed from the boiler and condensed to produce distillate.
After the first distillation, the low wines are collected, usually around 25% for whisky. The pot still is cleaned, and the once-distilled spirit returns to the still. But usualy the operation involves a series of two or three units. Second distillation or spirit run allows low alcohol wines to be re-distilled (often using recycled residues) to a strength of around 55–70% vol.
Three or more distillations produce an even purer and higher-proof spirit.
The fractionation process allows for precise cuts to craft flavour profiles and offers the opportunity to experiment with different ingredients and runs. So, the heads / foreshots (solventy, estery) are put aside, the heart is keep as new-make and the tails / feints (oily, heavier) are processed for the next run.
However, since still distillation is done in batches, it is labor-intensive. Therefore, continuous column stills are much better suited for multiple distillations.
Pots run in batches, columns columns operate continuously for several days so they differ in efficiency, and homogeneity. Still distillate typically has a lower alcohol content than neutral spirit, with the emphasis on flavor.
The congener profile typically retains heavier congeners (body, texture) with simple distillation, columns can be tuned for higher purity and lighter style.
In pots, the shape (height/neck/boil ball), the angle of lyne arm and the type of condenser determine reflux and sulphur removal; in columns, the number of plates/packing and the reflux ratio for measuring purity.
Single malt Scotch refers to single malt whisky produced in Scotland. Only about 10% of the Scotch whiskies on the market can be classified as single malt. All single malt goes through a similar batch production process.
According to Scottish regulations, “single malt” must be distilled in pot stills to qualify for this category. The whisky must be distilled at a single distillery from malted barley mash. Other jurisdictions may use column stills.
The originally distilled spirit, known as low wine, contains about 20–30% alcohol. The low wines is then pumped into the next still, known as the “spirit still”, and distilled a second (and sometimes third) time. The final product, called “new make spirit”, typically contains 60-70% abv. alcohol.
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.
Single pot still whiskey is a style of Irish whiskey produced by a single distillery from a mixed mash of malted and unmalted barley distilled in a pot still. If a whiskey is not completely distilled at a single distillery, it may be termed “pot still whiskey’, but not “single pot still whiskey”.
This style of whiskey has historically been called “pure pot still whiskey”, “Irish-style pot still whiskey”, or particularly in Ireland, “simply pot still whiskey”.
The resurgence in popularity has led some distilleries outside Ireland adopting similar production methods, creating whiskeys that imitate the Irish style. Due to differences in mash bill and local regulations, these products are referred to simply as “whiskey,” including single malt whiskeys and some bourbons and rye whiskeys.
