A question that is often asked is whether or not it is necessary to have a copper still for producing the best quality whiskey. Purists argue that there is no other proper way to do it and they point to the fact that is has always been done that way. Stainless steel advocates argue that it has been always done that way, because stainless steel was only 'discovered' about a hundred years ago, and in some industries, old habits die slowly. In defense of using stainless, they argue that stainless steel is more durable, easier to work with and less costly than copper.
There is a good reason to use copper for distilling. Copper catalyzes (allows to occur) certain reactions that remove undesirable notes/flavors in the distillate and make it 'smoother'. Without copper, the distillate will smell and taste sharp and unpleasant.
However, the still doesn't need to be made of copper. There is nothing particularly magical about the pot or column itself being made of copper. As long as copper metal is present somewhere in the still, the beneficial reactions can occur.
So there are good reasons to use a stainless steel still, and good reasons to include copper somewhere in that still.
An easy and inexpensive way to include copper is by the insertion of 100% copper scrub brushes. It is important to use 100% copper scrubs and two brands that make them are Chore Boy and Libman. Of the ones we tested, Chore Boy are generally less expensive but they are also about 30% lighter than Libmans.
For placement, several scrub brushes can be put in the stainless conical fermentor (pot still in this application), and they can also be placed inside the Condensing Assembly. The 1.5" to 2" reducer makes a great place to put several as the constriction will naturally hold them. As the distillate passes out of the 4-in-1 stainless conical fermentor it has to go through the copper brushes, allowing for maximum interaction (and even a bit of reflux for higher proof). For the stripping run (the first time beer is distilled) it is recommended to place the copper in the still itself, not in the Shotgun condensor Assembly, as 'burping' (proteins etc. foaming up into the condensor) can occur if heating is too rapid leading to fouling or plugging of the Condensing Assembly. In the spirit run(s)—redistillation of the distillate(s) collected from the stripping run(s)—the proteins are not present and fouling won't occur.