OK, thought I'd post after watching the Modern Marvels on Copper this week. I wondered if copper plating the inside of a keg for rain water, or any water for that matter, storage would be a good idea due to its anti-microbial properties. I ask here because of the pH question. I wouldn't want an excessive copper taste in my brewing water or anything so I wonder about the water and the copper oxidation being stripped off. I am going under the same principle as the settlers used for milk containers with a silver dollar in the bottom to help it "last" longer. Any thoughts? Oh, and for all the "copper plating is expensive" comments, my retort to that is I accidentally found out how to cheaply plate stainless with copper, lol. I plated my brand new all-stainless Sanke tap by leaving it in a bucket with spilled beer. The tap had a penny as a stopper in one end and only half the tap was submerged, but when I discovered the bucket I had a pretty pink tap.
This is just one of those what-if types of questions, but I am a curious person so I have to ask, lol.