Winemonger.com

A few days ago I received a call from a customer asking about white flakes he had discovered in a bottle of Trockenbeerenauslese by Gsellmann and Gsellmann.
What he had come across are tartaric crystals, commonly referred to as wine diamonds or Weinstein (”wine stone”) in German speaking countries.

He wanted to give this wine as a gift so I assured him that he could return the wine and replace it with a flake-free substitute of his choice. This is a tough one for your wine merchant: we understand that you don’t want to give a bottle of wine with the properties of a snow globe, but at the same time we know that you have bought a perfectly fine wine. Have you, really?

Opinions about this issue are divided and the reason is simple: you have bought flawless wine, but you have not bought aesthetically flawless wine, and depending upon where you are from, this can matter more or less.

The American wine drinker is not used to wine diamonds. Here most wines undergo cold stabilization, a process by which a wine is cooled down before it is bottled and the white flakes, “crystallized tartaric acid” , fall out and can be separated from the wine. But, as you might have guessed, by common rule a price must be paid for beauty: Cold stabilization influences the wine’s balance and taste. According to some winemakers, the wine is actually ripped apart, as the rapid cooling changes the wine’s colloidal structure.

A case of style over substance, one might say.

But there is another interesting correlation between wine stones and the quality of a wine: The longer the grapes hang on the vine, the more wine acid (the building block of wine diamonds) will accumulate in the grape. Furthermore, the more time the wine is given to ferment, the less wine diamonds will fall out during fermentation, but the more they will instead build later in the bottle.
In other words, wine diamonds are an indicator that the grapes ripened long and the winemaker fermented the wine slowly and with great care, both important precursors to high quality wines.

I thought that our customer would probably appreciate a statement from the horse’s mouth so I gave Hans Gsellmann a call. “Part of the grapes acid are tartrates, aka salt” he explained, “As the wine ripens these tartaric acid crystals fall out. It’s a natural process a wine will go through on its path to the peak in its development. When you see these flakes at the bottom of the bottle or on the cork, you can be almost certain that you are opening the wine at the right time. You should consider yourself lucky.”

In the old world, wine aficionados seem to seek out the wine stone as a sign of quality: It shows that the wine has not been robbed of its structure through unnatural chilling and it is a sign of a well-matured wine. There, due to the long history of wine making, people have become accustomed to wine stones and seem to accept them. If anything, the wine diamonds will have added roundness to the wine by subtracting some of the acid from it.

Our customer was glad about the news. Sending stuff back is “a pain” he informed me. He decided to buy a case of Feiler Artinger Ruster Ausbruch for his friend while he kept the Gsellmann and Gsellmann TBA for his private cellar. My kind of customer.

New technology developed in France promises to circumvent the colloidal issue: Electrodyalisis. Until every noteworthy winery has bought one of those fancy French machines (and that will be a few decades) this rule of thumb applies: Cold stabilization is like tossing out the baby with the bathwater. You are left with an aesthetically flawless (no weinsteins), but lesser wine.