After undergoing 1500 dishwasher cycles, Spiegelau stemware was certified as “extremely dishwasher safe” by an independent laboratory. They found no scratching, markings, loss of brilliance, foggy shadows, change in color or brilliance or build up of water chemicals and residue. Spiegelau’s remarkable durability can be attributed in large part to the Platinum Glass process. As the glass goes from its powder to its liquid stage, liquid glass is passed through platinum-lined tubes to eliminate any impurities and remove all imperfections and inconsistencies that might otherwise exist. (Platinum prevents leaching that may occur from other equipment linings) While more expensive, this innovative use of technology proves Spiegelau’s commitment to quality. The result is a "high performance" wine glass with a remarkable marriage of elegance, functionality and durability.