You may be familiar with Cream of Tartar. It’s commonly added to egg whites for meringue, it adds loft to baked goods and helps to make fluffier whipped cream. But, did you that Cream of Tartar is a natural by-product of the wine making process?

It comes from tartaric acid, a naturally occurring substance in grapes. During fermentation, the tartaric acid will form in wine making vessels and line the inside with a white sediment. The sediment is removed and ground into a fine white powder, which we know as Cream of Tartar.

Cream of Tartar is also known as Potassium Bitartrate or Potassium Acid Tartrate.

Tartrates are known in the wine industry as “wine diamonds.” Not only do they form in wine making vessels, but they can also appear inside a wine bottle or attach to the inside of the wine’s cork.

These tiny, crystalline deposits are completely harmless. But, winemakers use a process called cold stabilization to remove tartrates from wine before it’s bottled. It’s most is common for white wines to be cold stabilized because consumers commonly store white wines at colder temperatures, which increases the risk for these ‘wine diamonds’ to form in the bottle. Cold stabilization is done mostly for aesthetic reasons so that consumers doesn’t have to deal with the ‘diamonds.’

If you do find these ‘wine diamonds’ on the cork you can simply wipe them away with a cloth. Or, if you see this sediment in the bottle, you can simply decant it to leave the crystals behind. But, either way, don’t worry about seeing these crystals - they are harmless. And, very useful in baking! Cheers!