Store the bottles on their sides. If, by chance, you have an old bottle lying about and want to know how it tastes, there's no shortcut to popping the cork. Don't worry if the bottle or cork is dirty or if the wine has thrown a sediment in the bottle. If the level of wine is low it means wine has seeped out through the cork and been replaced by air - a bad sign although not always fatal. Old red wines tend to lose color and eventually turn brown.
White wines turn golden and then brown.
Make sure you swirl and stick your nose in the glass. Concentrate to find out what the wine has to say. The taste of old wines is usually drier than young ones, with more subtleties. Often there's a silky texture. At the end of their lives, wines become thin and mean.