The Role of Copper Stills in Alcohol Distillation
Copper stills are often underestimated in alcohol distillation processes, yet their role cannot be understated. Copper has many physical characteristics that make it ideal for making stills; such as malleability, heat absorption and transference capabilities as well as heat transference efficiency.
As an alcoholic liquid evaporates it passes over copper surfaces, where chemical reactions occur that remove unwanted compounds while creating new taste aromas and smoothness. This process takes time – the longer liquid interacts with copper the greater its effect is.
Copper pot stills can help neutralize sulfuric compounds produced during fermentation and transform them into less flavorsome substances by absorbing and converting them. Furthermore, they have the capacity to adsorb aldehydes that contribute harsh or unpleasant flavors by forming chemical bonds with them that break them down resulting in more refined spirits with enhanced tastes and reduced sulfur notes.
Copper amounts used by distilleries will differ depending on their still sizes, shapes, and methods of condensation; but in general more copper equals better spirits. Copper wears away over time in areas of the still where it sees greater action such as above the boiling line, swan neck, lyne arm condenser and beginning of worm; this results in black deposits or green-blue copper salts appearing that should be periodically removed for safety reasons or as soon as they reach critical thickness, monitored via ultrasound technology.
