A copper flute still is a sectional distillation column made of copper, equipped with copper plates and sight glasses to monitor the process.
These stills are used to produce various flavoured spirits such as whiskey, rum, brandy etc. The catalytic properties of copper help remove impurities and unwanted sulphur compounds from the distillate, resulting in a cleaner and more uniform product.
Copper is excellent at catalyzing reactions that remove unwanted sulfur compounds formed during fermentation. By removing these compounds, copper allows for the formation of fruity and floral esters, which are organic compounds responsible for the desirable aroma and flavor notes and a silky mouthfeel in spirits like whisky or gin.
By removing trays, the distiller can pass the alcohol vapor through the still, producing spirits with a richer flavor and character. The design can also be equipped with additional infusion chambers for botanical spirits such as gin or fruit infusions.
Copper flute stills have a modular design, allowing plates and sections to be added or removed. Using all the trays in the column and additional sections allows for increased the efficiency of the separation process, allowing the production of very high-proof spirits with a strength of 185-190 proof (92.5-95% ABV).
High proof spirit production is achieved by maximizing reflux through slow and steady distillation, especially in the 20-section model. To achieve high proof (90% and above), a slow and steady run is important. This ensures enough time for each vapor bubble to fully interact with the tray.