What is the white residue in bottom of a glass wine that has been frozen?

The white residue you see at the bottom of a glass of frozen wine is most likely tartaric acid crystals. Here's why:

* Tartaric acid is naturally present in grapes. It's a key component of wine's acidity and contributes to its flavor.

* Cold temperatures make tartaric acid less soluble. As wine chills, the tartaric acid becomes less soluble in the wine solution and starts to crystallize out.

* Freezing concentrates the wine. As the water in the wine freezes, the tartaric acid becomes even more concentrated, further promoting crystallization.

These crystals are harmless. They don't indicate spoilage or a problem with the wine. They're a natural part of the winemaking process and are perfectly safe to consume.

Here's a few things you can do about them:

* Don't worry about them! Just pour the wine carefully and enjoy it.

* If you find the crystals unsightly, you can try to dissolve them. Gently warming the wine slightly should dissolve the crystals.

* Don't freeze wine too often. Repeated freezing can lead to more crystal formation.

Let me know if you have any other wine-related questions! 🍷