One Thursday afternoon, not too long ago, I was sitting at a local sports bar enjoying a whiskey and a Mavs game. My companion, perhaps against her better judgment, ordered the house red, a Pinot Noir. Out came the glass: Pigeons-blood ruby, filled a half-inch from the brim, and speckled with shards of a glass-like substance which reflected the red and blue neon from the walls like a big pinch of glitter.
“Hey, is this wine all right?” the wine recipient called out, holding up her glass. It was loud enough for the bartender (who had busied herself with the dish machine) to hear, if she had wanted to.
No answer came. I vaguely recalled reading something about crystallized wine in a book once. After a long pause, I ventured, “I think so.” A couple minutes of tipsy web searching ensued: Something something “tartaric acid,” something something “minimal processing.”
Yeah, okay–thanks Google. We had satisfied ourselves that the sharp crystals were not undissolved detergent, chipped glassware, or some other “Kitchen Nightmares”-esque horror that might cause injury or regret. My companion sipped the wine.
Finally, the bartender turned around from the dish machine. “Yeah, it’s fine. My manager says it’s fine. It’s a natural, like, wine thingie.” A pause. A staredown. “I could get you something else, but I’m pretty sure the white wine has them, too.”
No thank you, no need. I gamely helped finish the “probably fine” wine, the gritty shards clinging to the sides of the glass and spoiling the last few sips.
Now, there’s a couple of different morals you could take from this little tale. One of them is, don’t order wine at a sports bar or breastaurant. (Duly noted.) But another might be this: Don’t leave your customers to puzzle over strange precipitates, urgently research obscure science facts, or drink sand when they’re just trying to enjoy a quaffable, chillable red at 5 PM.
A little background for those who, like me, have a hard time recalling their high school chemistry class: “Wine diamonds” (a.k.a potassium bitartrate) are formed from the interaction of tartaric acid and potassium. Tartaric acid is one of the main acids that gives wine its tart taste. Potassium–an element that the roots of grapevines draw up from the soil–is one of the many solids dissolved in wine that usually stay dissolved. At cold temperatures, the dissolved compounds precipitate out–ungracefully un-dissolving themselves and settling like wine dandruff to the bottom of a glass or bottle, or clinging to the cork like stalactites.
These crystals are more commonly found in white wines than red, due to their service temperature. Once the crystals form, they tend to not dissolve again even if the wine is brought up to a warmer temperature. The sports bar in my story keeps both their red and white house wines on tap in a beer cooler, so they doubtless see colder temperatures than most wine ever will. Even so, an ice bucket or home refrigerator can easily be cold enough to trigger the formation of tartaric crystals.
The wine industry knows this, of course, and so has developed the process of cold stabilization. It’s a pre-bottling step that involves (at its simplest) chilling the wine in a tank, then filtering out the crystals before they can ruin someone’s happy hour. Sometimes more potassium bitartrate is added to “seed” the crystals. Cold stabilization is the norm at large commercial wineries, especially for wines that will be stored or served chilled.
Why doesn’t everyone do this, all the time? Well…
Winemakers come gallantly to the defense of their wine diamonds. Sometimes effusively so. To ease the apprehension of wine drinkers, they argue that actually–perhaps counter-intuitively–the floating chemical bits are a good thing. They’re supposed to be taken as an indicator of nutrient-rich soils, ripe grapes, and low-intervention winemaking practices.
“Diamonds are a wine’s best friend,” opines Witches Falls winery of Queensland, Australia. Says Vine Cliff Winery of Napa, California, “Now you know that it is time to celebrate when you find wine diamonds in your glass.” Chemically, it’s the same stuff as cream of tartar, both websites point out–as if I love to sneak little spoonfuls of cream of tartar from the pantry.
Let’s call wine diamonds what they are: If not a contaminant, then at least a nuisance. A bitter, acidic, itchy crud that has no place in my glass. I may no longer feel apprehension when I see wine diamonds…but the feeling is a long way from affection.
My objection is mainly an aesthetic one. Floating bits of stuff are a distraction from the color and clarity of a beautiful wine. They also feel gritty on on the lips and tongue–and “gritty,” in the world of food and beverage, is rarely a compliment.
An oyster should not be gritty. A crème brûlée should not be gritty. Even southern grits–which have “grit” in the name–are not generally described as gritty by people who are trying to sell them. (Check the menu next time you’re at a brunch–I’ll bet you a nickel they’re described as “creamy gouda grits,” or with some other moderating adjectives.) A wine, as I believe common sense and common taste dictates, should also not be gritty.
But tartaric crystals are an intrinsic, historic part of wine! It’s true, cold filtration is a product of modern technology including industrial refrigeration. But we used to have all kinds of things in wine that shouldn’t be there–bugs, dregs, traces of lead, pesticides, and other ickiness. Now most of the world’s wine is both safe and delicious. Over time, winemakers have developed techniques for removing danger and unpleasantness from our glasses–innovations that should be lauded.
But it’s natural! So is a freakin’ chicken bone–but that doesn’t mean I want to chew on it. Wine crystals don’t bother me as much in an older vintage wine, where they may have formed over time, after the winemaker’s attention is long gone.. But to let them rattle around inside a mass-produced, early-drinking wine just seems like an odd choice.
And it is a choice. Rolling Forks Vineyards of Minnesota (whose wines do undergo cold stabilization) points out that the chilling and filtration process presents a dilemma: “It removes aromatics and subtler notes from the wine’s flavor profile, leading to a duller smell and a difference in feel on the palate. If you were to take two wines from the same harvest of the same year of the same grape variety, put one vintage through cold stabilization, and leave the other without, the wine that wasn’t stabilized would potentially have a different profile and mouth feel.”
I do not doubt that this trade-off is real, and it must be why many small producers choose not to remove the crystals. I’m not a winemaker, so I can only give a consumer’s ignorant perspective here. But what I do know is that there all kinds of processes that affect or perhaps diminish the natural aromas found in wine, and yet somehow we get thousands of wines on the market that taste great and aren’t full of scratchy, sour little rocks.
Look, I know that great wine doesn’t have to perfectly clear. I’m a lot more tolerant of sediments from grape skins or pips. They may not always be easy on the eyes, but at least they’re something which is recognizably a part of a grape.
Also, there’s a standard, wine-expert approved technology for dealing with sediment: It’s called a decanter. Decanting is technically an “intervention,” too–but it’s something that contributes positively to the overall enjoyment of a glass of wine. So if you don’t want to serve wine that’s been chilled and filtered, it is too much to ask to just…decant out the crystals?
Back at the sports bar last week, I noticed a new-ish bartender diligently straining the house Pinot out of the chilled tap, through a paper coffee filter, and into a glass carafe. “Wine diamonds?” I asked knowingly. “Yeah,” she said. “I gotta do this, or else everyone will complain about the wine or send it back. It’s a pain in the butt.”
“But they’re natural!” I offered. She rolled her eyes.
So there you have it, tartaric precipitation: Bartenders hate you, diners fear you, and the winemakers that defend you doth protest too much. Shine bright, wine diamonds–but not in my glass.
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