Wine glasses come in an often-bewildering variety of shapes and sizes. Different styles of wine are best sipped from a glass designed to highlight its positive attributes. Although there are many variations on the glasses, those made for red wine tend to be similar, while white wine glasses also have some design traits in common.
Although there's a wide amount of variation in glass shape and size, red wine glasses tend to have broader bowls and wider mouths than glasses intended for white wine, which tend to be slightly narrower. The reason for the difference lies in the chemical reactions wine undergoes after you open it.
Glass Shape and Chemistry
Contact with oxygen, or aeration, causes a chemical reaction called oxidation that releases the wine's characteristic aromas and softens its flavors. This is particularly important for younger red wines, which may contain more tannins, the bitter, astringent chemicals also found in tea. This is why wine experts recommend exposing red wine to air -- allowing it to "breathe" -- before serving it. The more the wine comes into contact with air, the more effective this process is, which is why red wine glasses are typically wider; the wider glass exposes more of the wine's surface area, speeding up oxidation. White wines benefit less from oxidation, which is why white wine glasses tend to be narrower.
The All-Important Nose
The aroma of a glass of wine helps to enhance its flavor; as a result, wine glasses are designed to release aromas in the wine and then focus them on the drinker's nose. The wide mouth of the glass gives you room for your nose, while the inwardly curving shape helps concentrate the vapor from the wine. This is true of both white and red wine glasses.
Red wine glasses come in a range of styles; Pinot noir and Burgundy glasses are full-bodied and rounded, with Burgundy glasses having a slightly flared mouth. Bordeaux and cabernet sauvignon glasses are slightly more narrow. The shapes vary depending on the aeration needs of each variety of wine. Similarly, white wine glasses also vary in shape. Chardonnay glasses are broader and wider, much like shallow red wine glasses; narrower glasses would concentrate the aromas of this oaky wine too much.