Crunchy wine? What??
We all like a good wine we can sink our teeth into, but not loose a filling!
Not to worry, this is not an accident in bottling which has rendered glass shards in your favorite Chardonnay. The crystals that you might find occasionally are really tartrates. They appear as small crystals that look like broken glass, and are totally harmless. In fact, Cream of Tartar is a by product of the wine making industry - it is these same tartrates that have been ground into a fine powder.
Tartaric acid naturally found in wine will precipitate (to separate from a solution or suspension) just below the freezing point. We do this in a cold stabilization tank, however it can happen again with remaining tartaric acid if the wine is exposed to cold temperatures after bottling. Very cold fridge, sitting left in the car in December, busted furnace, etc.
Why do we do it?
In order to remove the tartaric acid from the wine, we cold stabilize it at 28 degrees fahrenheit so the acid crystallizes, and then we are able to filter it out in it's solid form. Tartrates can vary from small deposits on the cork looking rather like fine glitter, to small crystals that settle at the bottom often referred to as 'wine diamonds'. These are totally harmless if ingested, and there are several bottle stoppers/pourers you can buy that have screens to catch them. (We sell these too!!)
Wikipedia has an informative article on wine acids, that even I - a straight D student in high school chemistry - can get the point of!
(Hey, I was an art major - give me a break!)
Acids, pH, precipitates, conversions - reads like a juicy romance novel for the wine savvy. For the rest of us who simply enjoy wine, it is a mystical concoction the origins of which we may never completely comprehend, and we can not help but be entranced by wine's magic spell.