To fully appreciate different grape varieties and their subtle characteristics, it is useful to have a glass shaped to bring out that varietal’s unique aroma and flavor. In general, red wines require glasses with a large bowl, and white wines need a medium-sized, slightly narrower glass. Also, the glass should not be over-filled in order to allow the wine’s aroma to fully express itself. If serving red wine you should generally pour four to five ounces per glass and three ounces for white.