I made up a pot still (beer keg, propane burner,2" x 24"column with a 30" 3/4" liebig) and did the vinegar cleaning proceedure recommended followed by a sacrificial spirit run. The equipment was disassembled, water rinsed and put away. The next run I did was a stripping run of 40L 18% port style wine with 25 ppm SO2 that I had made and didn't care for . The equipment was assembled dry and ran. I diverted the initial product into a 140 ml jar and a good thing that I did as it was a green color!!? All the following product was colorless and started at about 70%. I ran for 2 hours until it was down to 40% and stopped for dinner with about 8L of product. I am assuming that the green color was caused by oxidation of the copper but am unsure as to why this would occur. Would any remaining moisture remaining in the equipment after rinsing with water be the culprit? Should I not be rinsing after using? Something else?