Depending on what type of sparkling wine is being produced, the key feature for the grapes is to be either neutral (for Champagne, for example) or flavourful (for Lambrusco o, for example), but they are usually high in acid to ensure that the sparkling wine is refreshing. Sparkling wine grapes can be either white or red. Red grapes are often pressed for sparkling wine without contact with their skins, which yields a wine juice.