Wine Diamonds: Little Gems in the Bottom of Your Wine Glass

Most wine drinkers are not excited about finding sediment, crystals or anything else in the bottom of their drained wine glass. I keep an open mind about these things. Admittedly it doesn’t happen too often, mostly just some sediment with an older red wine (which makes me very happy as I appreciate the transformation an older red wine makes in the bottle), but recently I was treated to a little surprise.

wine diamondsI was enjoying a flavorful glass of Brunello at a wine gathering and as I sipped down to the last bit in my glass I noticed a few small, granular, ruby-colored clumps in the bottom of my glass. I carefully drained the last drops of wine from my glass and set about inspecting these little nuggets. They were unlike sediment which is silty and ruby-colored. These looked like little wine-colored stones. Wine diamonds!

I have read about wine diamonds, technically tartrate crystals, and know they form from tartaric acid the most common acid in both grapes and wine. These crystals can collect on the bottom of a bottle of wine or form on the bottom of the cork inside the wine bottle. They are harmless,  really just an indication that the wine was probably not overly manipulated and that it is a living product with a dynamic chemistry.

When they form in a white wine they do look like diamonds, I have seen striking pictures of them. In the case of my glass of Brunello, I was left with little crystals in the bottom of my glass which had taken on pigment from the Sangiovese. More like wine rubies to me!

I have yet to find wine diamonds in a glass of white wine, but you know I will remain vigilant always inspecting the contents of every glass of wine I enjoy looking for wine diamonds. When I find them I will report back. Wine provides enjoyment on so many levels!


Reference: Bird, David (2010) Understanding Wine Technology: The Science of Wine Explained. San Francisco: Wine Appreciation Guild. pp. 157-164.

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