Tartrates – those glass-looking things at the bottom of my Chardonnay
Posted by Genevieve Rodgers-Llerena on January 10, 2008
So there you are, you’ve just cooked this amazing gourmet meal for your close friends who, like yourself, happen to be HUGE wine fans. Everything is prepared, the apps are ready, the table is set, and you’ve anticipated every eventuality. Knowing that your friends are due to arrive in five minutes, you reach into the fridge to pull out this great white wine you found at an out of the way winery in Healdsburg only to find it not there. Looking around you spy it on the counter – it’s warm. But, thinking quickly, you open up the freezer and stuff it in the ice tray. No problem. That is until you take it out and find that your boutique white wine now has little grains of glass-looking crystals floating in your bottle. Does this sound familiar?
When this happens to you, the key is Don’t Panic! There is no cause for alarm. The crystals are tartrates that were happy enough to be soluble at room temperature, but not so soluble at the low temperature of the freezer. The crystals are generally caused from tartrates precipitating out of the wine at cold temperatures. Tartaric acid is naturally found in grape juice, as are tartaric salts – Potassium bi-tartrate and Calcium tartrate. They are part of what makes wine wine. Unfortunately, these tartrates are not very soluble at higher alcohols and lower temperatures.
So, how does this happen? When the wine is chilled, some of the acid and salts become insoluble and form small crystals. Sometimes, when the crystals link and grow, they look almost like glass shards. The crystals may float in the wine, fall to the bottom of the bottle, or attach themselves to the cork. Please note: they pose NO HAZARD, nor do they change the taste or smell of the wine. Usually this occurs in white wines and is rare in reds. Most wineries will subject the wines to very cold temperatures before bottling to encourage the crystals to drop out of the wine in the tank. When wines are cold stabilized in this way the crystals will generally, but not always, be inhibited in the bottle. The chillers necessary to cold stabilize wine are quite expensive so small boutique wineries may not be able to invest in them and so may have a higher incidence of crystal formation. Also, wines that are unfiltered and unfined may have more crystal formation. Besides large changes in temperature, age can cause tartrates to precipitate into the bottle
If you notice a particular wine has a lot of crystals in it, try not chilling it as cold. This will mitigate the amount of crystals. Let your bottle rest upright for a while to let these crystals fall to the bottom. Pour your wine, carefully leaving the last bit of wine in the bottom of the bottle, along with the crunchies, and, enjoy! These boutique and small production wines may not always look as pretty, but they make up for it in the unique flavors that are a result of the artistry.