Crystals sediment in my wine?
Fortunately, these crystalline sediments are not only the least likely to taste bad, but are treated by some as a sign of a better wine. So if you find crystal sediment in your wine glass, there's no reason to worry or fret. The crystal sediment you might find in a wine glass is called tartrate and forms from tartaric acid in grapes. Not all fruit has tartaric acid and its presence in grapes is what allows us to make better wines from grapes than can we can from any other fruit. Because tartaric acid doesn't remain dissolved in alcohol as easily as it does in grape juice, it binds to potassium after fermentation and forms potassium acid tartrates — the crystalline solids creating the sediment in your wine glass. Because red wines have probably been exposed to cold temperatures less than white wines, they are more likely form tartrate crystals.
In theory all wines should probably form tartrate sediment, but modern wine production has introduced cold stabilization and fine filtration which remove most to all tartrates. More expensive wines that have been created according to more traditional methods, thus eschewing cold stabilization and filtration, are more likely to produce tartrate sediment. People who prefer the traditional methods of wine production, which includes a lot of wine drinkers around the world, will treat the presence of tartrate sediment as a sign of quality.
The tartrate sediment in your wine glass or wine bottle won't hurt you if you consume it and it isn't going to ruin the flavor of your wine, so you don't need to worry about separating the crystals from your wine before serving and drinking. However, there is also no value in consuming this sediment so don't go out of your way to do so.
I copied this discription from the internet, I would add, after the acid in the wine crystalizes and drops out that the wines become much softer. This is why the traditional method of wine making is so popular.