The most definitive debunking of the mushroom myth can be attributed to the 1990 volume of The Curious Cook by Harold McGee in which he performs an experiment (via HuffPost). McGee weighed a pile of mushrooms, soaked them for five minutes, and weighed them again. The mushrooms only gained about 1/16 of a teaspoon of water, showing that a mushroom is not actually a sponge, and alleviating flavor concerns everywhere. Unfortunately the “washing myth” still persists today.
As one social media user added to Alton Brown’s Twitter conversation, “This is true! You don’t want them to soak but a quick dunk/rinse adds negligible moisture.” Another reader jests, however, “But is there a way to wash them WITH creating said Black Hole? Because… Delicious Everything Flavored Mushroom…”
If you’d like to know the best way to wash your mushrooms, try placing them in a salad spinner (via Cooks’s Illustrated). Add water and scrub ’til the dirt is gone, then rinse. Use the spinner to remove any excess water.
And if you still really don’t feel comfortable washing mushrooms, another Twitter user reminds us the value of DIY, “Non issue when you grow your own and go straight from substrate to plate.”