The hidden crystals in red wine

In the last few months, we’ve learned about what high acidity does to wines, what can happen when wines are infected with a certain fungus, and also how exposing white wine to lower temperatures causes a phenomenon known as “wine diamonds.” So, the next logical question for this month is, “Can red wines also contain ‘wine diamonds?’”

Let’s again turn to our local expert, Jim Sperk of the Northern Ohio Wine Guild, for the answer to this one. 

“It certainly is possible, but you may never see wine diamonds in reds,” Jim says. “For one thing, red wines are not quite as high in acid as white wines. So, they would not generate quite as much unstable potassium bitartrate. Some, but not all, winemakers will still use the same cold stabilization process they use for white wines to precipitate the tartrates from the wine.”

Jim says that there is also an opacity difference between the white and the red wine. Most white wines are nearly transparent or translucent, while red wines have much less light passing through. 

“If the wine diamonds are there, they may not be visible in red wines,” Jim says. “Finally, as stated last month, those wine diamonds are the tartrate that precipitates if the wine is chilled sufficiently. White wines may be stored in a refrigerator for a week or two. That’s when wine diamonds begin to appear. Red wines typically are only chilled in the fridge for an hour or so before being served.”

Red wines usually don’t spend enough time in colder temperatures to fully develop the tartrate necessary to develop wine diamonds. Also, the long barrel-aging process for red wines allows these natural crystals to settle before the bottling process occurs. 

Jim notes that there are times when you will find crystals in your red wine, and that will usually be on the bottom of the cork or even at the bottom of the bottle. 



“And if you’re concerned about the look or taste of any wine diamonds when you’re serving a special bottle, there’s a simple solution,” Jim says. “Just decant the wine and leave the crystals behind.”

For information about the Northern Ohio Wine Guild, contact Jim Sperk at tinymoonwines@usa.net.