Have you ever found crystals in your wine? Those crystals are simply acids — titratable acid to be precise. Titratable acid crystallizes out of suspension at cold temperatures.
Your wine can be exposed to extremely cold temperatures if your wine is left in your vehicle too long, your fridge is too cold and heaven forbid, you put your wine in the freezer. Also, when wines are shipped, especially in the cooler months, they are frequently exposed to temperatures low enough to allow these crystals to form, and they commonly grow attached to the cork or are found at the bottom of a bottle.
White and red wine can both produce these dazzling additions. Much like the sediment of red wines, these crystals are simply extra stuff that the wine doesn’t need anymore. They are completely harmless but we do recommend to decant your wine to ensure they don’t make into your glass. These crystals can have a bitter taste and not to mention they have a bizarre texture that ruins your tasting experience.