Copper is biostatic, meaning bacteria will not grow on it.
During distillation, copper can reduce sulphur compounds such as dimethyl trisulphide levels in the liquid. Copper can do this more effectively in some parts of the pot stills than others. It is not an overall copper effect. Studies have found that the wash still condenser and the spirit pot are most effective at removing this compound. Also, copper stills need to be “worked” to be good at removing these sulphur compounds – new copper doesn’t do it so well.
In damp air copper slowly forms a beautiful green blue surface film called patina or verdigris. This forms naturally to protect the copper from the damp. This effect can be observed in the Islay Whisky Connection logo image.