Copper vs Stainless Steel

Sulphur and meatly aromas from stainless steel distillation units.

“The presence of copper in pot stills was confirmed as being important for the control of sulphury and meaty aromas in new make spirit, and DMTS levels showed a good correlation with these aromas. In these laboratory-scale distillations, copper was found to reduce the level of this compound best when placed in the wash still condenser or spirit still pot. In order to improve control of this compound, the reasons why these areas of the stills are more efficient than others at reducing DMTS need to be elucidated. Copper in the spirit still condenser also appeared to play a role in controlling sulphury and meaty aromas, but the mechanism for this effect is, as yet, unclear. These results suggest that removing copper from any of these sections in industrial-scale stills is likely to have the most significant impact on new make spirit aroma.”
The Impact of Copper in Different Parts of Malt Whisky Pot Stills on New Make Spirit Composition and Aroma
Barry Harrison*, Olivier Fagnen, Frances Jack and James Brosnan
J. Inst. Brew. 117(1), 106–112, 2011