Wine can be classified in various different ways, each of which as important as the other, depending on your intention.
   The first classification is by vinification methods. These include classifications such as sparkling, still, fortified, rosé, and blush. The color of wine is not determined by the juice of the grape, which is almost always clear, but rather by the presence or absence of the grape skin during fermentation. Grapes with colored juice, for example alicante bouchet, are known as teinturiers.
   Red wine is made from red (or black) grapes, but its red color is given by a process called maceration where the skin is left in contact with the juice during fermentation. White wine can be made from any color of grape as the skin is separated from the juice during fermentation. A white wine made from a very dark grape may appear pink or 'blush'. A form of Rosé is called Blanc de Noir where the juice of red grapes are allowed contact with the skins for a very short time (usually only a couple of hours).
   Sparkling wines, such as champagne, are those with carbon dioxide, either from fermentation or added later. They vary from just a slight bubbliness to the classic Champagne. To have this effect, the wine is fermented twice, once in an open container to allow the carbon dioxide to escape into the air, and a second time in a sealed container, where the gas is caught and remains in the wine. In most countries except the United States, champagne is legally defined as sparkling wine originating from a region in France.
   Fortified wines are often sweeter, and generally more alcoholic wines that have had their fermentation process stopped by the addition of a spirit, such as brandy. By this process wines are produced with a greater amount of residual sugar. Fortified wines such as Port or Sauterne are traditionally drunk at the end of a meal.
   Brandy is a distilled wine. Grappa is a dry colorless brandy, distilled from fermented grape pomace, the pulpy residue of grapes, stems and seeds that were pressed for the winemaking process.
   The second means of wine classification is by taste - their primary impression on the drinker's palate. Wines are made up of chemical compounds which are similar to those in fruits, vegetables, and spices. Different grape varieties are associated with the aromas and tastes of different compounds. Wines may be described as 'dry' (meaning they are without obvious sugar), off-dry, fruity, or sweet, for example. Sweetness is in actuality determined by the amount of residual sugar in the wine after fermentation, relative to the acidity present in the wine. Dry wine has only a tiny amount of residual sugar.
   You can also classify wines by their vintage – the year in which they were harvested. Vintage wines are made from grapes of a single year's harvest, and are accordingly dated. Some wines can improve in flavor as they age, and wine enthusiasts will occasionally save bottles of an especially good vintage wine for future consumption.
   Most countries allow a vintage wine to include a portion of wine that is not from the labeled vintage. For some types of wine, the best quality grapes and the most care in wine making are employed on vintage wines and they are therefore more expensive than non-vintage wines.
   Another means of classifying wines is by styles such as Dessert wines, Fortified wine, Fruit wines, Rose wines and Sparkling wines.
   Or you can classify wines by their quality which will range from cheap to premium (with matching prices). Red wines tend to fetch the highest prices because of their ability to form more complex subtleties. Most premium wines are only at their best many years or even decades after their bottling. However, some wines can spoil when kept stored for so long a period. This helps account for prices that can be in the thousands of dollars for a bottle, because if you have three bottles of a particular vintage, it is possible that one or two of them may be spoilt and restaurants have to take into account the fact that some bottles will be returned.