What’s the white powder on grapes? Is it a pesticide?

You may have noticed a whitish coating on certain fruits. It’s particularly visible on grapes, plums, and blueberries. It’s epicuticular wax, also known as “bloom,” a natural and harmless part of many plants. The coating protects the plants and seals in their moisture. It’s what makes water slide off fresh kale, and it gives blue spruce trees their distinctive color. You can also find in on certain succulents.

Fruit in the supermarket has often been artificially waxed to make it last longer and look more appealing, and because the process of picking and washing it stripped it of its natural protective coat. Sometimes, epicuticular wax from other plants is used. Carnauba wax (which can be found in everything from cosmetics to furniture polish) comes from a species of palm tree that grows in Brazil; the wax is harvested by beating the dried palm fronds. Other petroleum-, shellac-, vegetable-, or beeswax-based waxes may also be used.

According to Consumer Reports, there is concern that the wax coating may help trap pesticide residue. They recommend buying organic when possible and making sure to thoroughly wash produce. In an article from October of this year, Catherine Roberts suggested that soaking fruits and vegetables in a baking soda solution may be effective in removing some pesticides.

We got our information from ThoughtCo, Consumer Reports, The Atlantic, Succulent Identifier, Washington State University’s Tree Fruit Research & Extension Center, The Demystified Vine, and The Botanist in the Kitchen. If you want to learn more, Aliza Green’s Field Guide to Produce and Melissa’s Great Book of Produce by Cathy Thomas both give tips on how to buy, store, and use fresh fruits and vegetables, while Richard Gianfrancesco’s How to Grow Food and Barbara Pleasant’s Homegrown Pantry explain how to grow your own.