If you clean mushrooms under running water before cooking them, chances are they’ll turn out soggy rather than tender and al dente.
“Unfortunately, mushrooms are quite literally sponges,” says Michael Scelfo, chef-owner at Alden & Harlow, Waypoint, and The Longfellow Bar in Cambridge, Massachusetts. The fungus is already water-dense, so once it soaks up more H2O it’s nearly impossible to cook out the unwanted extra moisture.
That said, washing is an important step since mushrooms typically have peat moss or soil on them when you buy them. Scelfo recommends two better cleaning techniques: The first is to quickly dunk the mushrooms in water, set them on an absorbent towel, and pat them gently on top with another. (If you use this method, wait 20 to 30 minutes before cooking so they can dry.) The second, and Scelfo’s favorite, is to simply rub the mushrooms with a damp cloth until you don’t see any dirt.
THE BOTTOM LINE:
You can use the above tips for all varieties, but it’s less necessary for types such as maitake and lobster, since they’re naturally dry and have lower absorption rates.