I'm making a cooling beverage dispenser for carbonated drinks. The keg remains room temperature and the beverage rises through a pipe that's coiled up inside a cooling unit filled with water or alcohol.
My first choice would be copper tubing because of its conductive properties, but I remember reading somewhere that it could lead to some kind of chemical reaction that would be poisonous? As I usually prefer not to kill my guests, and avoid it whenever possible, I'd like to find a good alternative that's able to cool the liquid as quickly as possible. I don't actually know what they were referring to or whether or not they were even right, I'd like some input on the uses of copper or aluminium for the piping or whether I should go with stainless steel.
I'd also like to use this for carbonated water, which might be very carbonized and I want to be able to sanitize the system by running a sanitizer like Star San through it.