It's common to pick wine on the basis of prices and brewing time. Actually, you can distinguish good wine from the bad with help of wine crystals.
It is a kind of crystallized substance in wine when it is stored in cold places. Wine crystals are in different shapes and some are sticky, attached at the bottom of wine bottles or corks. Its major ingredients is DL-Tartaric acid(133-37-9) which is one form of tartaric acid. As for sherry, it looks like white sugar; for clarets, it is in colour of purple with slight acidity.
If wine crystals are in wine of young age, the could be rich in high in minerals. It is more likely to happen to vintage wine for years. Crystals on oak plugs or bottles are signs long time storage. Sometimes, we can find wine crystals in wine of young age, which proves that the wine is very rich in high in minerals. It is more likely to happen to vintage wine for years. Crystals on oak plugs or bottles are signs long time storage. They can be called as "old crystals".