When we grow up with little tricks a loved one taught us in the kitchen, rarely do we ever ask why those tricks actually work. Even more rarely do we challenge the notion that those hacks work at all, or if they’re just a force of habit that has simply never hurt. Case in point: cucumber rubbing.
No, this isn’t some sort of innuendo. Get your mind out of the gutter (or take it to a different article). Call it an old wives tale—or call it “milking,” as some have been doing recently—but Mexican cooks and many others have long used this trick to get rid of the bitterness in a cucumber.
Here’s how it works: You slice off the ends of a cucumber, then use the exposed flesh of one of those pieces to rub against the exposed flesh of the cucumber in circular motions. This will cause a white filmy substance to seep out of the cucumber, which is why some have rebranded the practice as “milking.” That white stuff allegedly contains the bitterness of the cucumber, so rubbing it out makes the produce sweeter.
Iowa State University explains in its Horticulture and Home Pest News that cucumbers as well as other produce (melon, zucchini, watermelon, pumpkin), contain a compound called cucurbitacin. This compound is mostly concentrated in the stem, leaves, and roots of the cucumber plant, but can spread to the actual cucumber fruit when the plant is under stress. That’s right: Plants have feelings, too. In the case of cucumbers, stressful situations involve hot, dry weather.
Other sources say that the cucurbitacin compound occurs more often in the skin of the cucumber plant. Regardless of where on the plant the compound is concentrated, that is what’s responsible for imparting a bitter taste.
Many people attest that this cucumber rubbing really does work, from TikTok users to Reddit posters—but does science actually back this up? Gustavo González Aguilar, a researcher at the Center for Research in Food and Development in Mexico, explained the science to The Mexicanist.
Aguilar busts this myth wide open, saying that as a fruit ripens its levels of cucurbitacin compound decrease, thereby reducing the bitter taste. As long as you’re working with a ripe cucumber, it doesn’t matter whether or how you rub it. No amount of rubbing will affect the flavor.
The many cooks who continue to cut and rub their cucumbers would argue that science can’t compete with their taste buds, and they’re welcome to keep doing exactly what they’ve been doing. If you think your cucumber could benefit from a little rubbing, there’s no harm in that—rub away, my friends. And yes, that was a bit of innuendo.