Language selection


Crystal shards in wine (wine diamonds)

Occasionally, you may find tiny crystal shards in your wine that you could mistake for small pieces of broken glass. These are called wine diamonds, otherwise known as tartrates. Although they may leave a slight gritty texture on your tongue, they are harmless and safe to consume.

wine diamonds next to a ruler measuring less than 3 centimetres

On this page

Occurrence of wine diamonds

Wine diamonds are tiny, crystalline deposits found in some wine. They can occur if the wine is exposed to temperatures below 4°C, when potassium and tartaric acid, both naturally occurring products of grapes, bind together to form a crystal. The crystals can be found at the bottom of a wine bottle or cork.

The presence of wine diamonds is viewed by many winemakers as a sign of high quality because it means that the wine was not over processed. Wine diamonds do not impact the taste of the wine.

Product safety

Although wine diamonds may leave a slight gritty texture on your tongue, they do not pose a health risk and are safe to consume.

How to prevent wine diamonds

Commercial wineries can prevent wine diamonds through a process called cold stabilization. After fermentation, they drop the temperature of the wine to near freezing for 3 to 4 days. This causes the wine diamonds to separate from the wine and stick to the sides of the holding vessel. When the wine is drained from the vessels, the wine diamonds are left behind.

What to do if you find wine diamonds

Wine diamonds are completely natural, harmless and safe to consume. However, you can take the following measures if you find them in your wine:

If you think the crystals may not be wine diamonds, you should report it to the CFIA.

Date modified: