I plan to use copper piping to support and water grapevines, I am wondering if the minute amounts of copper that is sure to dissolve with the constant water running through the perforations I will make, will in any way affect the health, taste, and so forth of the grapes.
Not at all. Copper trellises have long been a favorite for growing grapes around the house. Copper is a essential micro-nutrient of plants, so any effect on the plant would likely be positive. As for taste of the grapes, I don't know for sure if you might get a copper taste on the grapes or not if you ate them right from the vine, but I doubt it. Washing them should take care of any copper taste if you did. If you live in an older house your water is probably coming through copper pipes already anyway.
