At the very beginning of the production of alcoholic beverages, many metals were used to make distillation stills (copper, iron, tin, aluminum, alloy-stainless steel, etc.), but copper proved to be by far the best metal that has been in use for thousands of years precisely because of its:
1. physical design benefits
2. excellent thermal conductivity
3. corrosion resistance
4. and most importantly its catalytic role in the quality of the distillate obtained.
Distillates obtained from an apparatus of glass, stainless steel, or other materials have poor organoleptic characteristics. Copper binds the sulfates and sulfides from the mash helping the spirit achieve a pleasant aroma that adds to the quality of the final distillate.
Copper is the best thermal conductor and has a very positive effect on the taste and smell of distillate, it performs better than any other metal and therefore the distillate itself made in copper vessels has a nicer smell, taste, and quality.