Food - Drink
Is It Okay To Eat The White Powder On Grapes?
When you buy grapes, you may notice a fine white powder or cast on their skins. This powder is called a “bloom,” and is really made up of a type of wild yeast called saccharomyces cerevisiae, which translates to brewer’s yeast; a by-product of this yeast is oleanolic acid, which helps trap moisture and prevent decay in fruit.
If you've ever been put off by the bloom on grapes, know that not only is the bloom safe to eat, but it's also part of the grapes' "terroir" or flavor profile, says Bon Appétit’s Brad Leone. However, Leone adds that if your grapes are not organic, it's best to forget about keeping the bloom intact and wash your fruit to avoid consuming pesticides.
The type of yeast that creates the bloom on grapes is the same yeast that causes fermentation in wine. The yeast settles on the fruit because it's attracted to the sugar inside, and if left to sit, the bloom merely acts as a protectant, but if you break the skin of the fruit, the yeast gets inside and a fermentation process begins.