Some sources insist yes; others say no. We tell you exactly what you need to know.
They grow in dirt, but they’re not plants. Their resilient flesh has more in common with lobster shells than neighboring flora. And unlike almost any other foods you can think of, they’re virtually impossible to overcook.
Cleaning mushrooms has never been straightforward either. Some sources claim washing is necessary and fine, others insist that it will bloat them and thwart browning. Still others say they should be wiped clean without any water at all.
The bottom line: Unless they’re foraged, most mushrooms do not need to be cleaned. If you want to clean them, it’s best to avoid using water on mushrooms with exposed gills, which will absorb the moisture and prolong cooking times.
These days, most mushrooms are farmed indoors and are very clean. Any dreck on them is just growing medium, and is OK to eat.
Though mushrooms secrete proteins called hydrophobins that help them repel water, the exposed gills on varieties such as portobello, shiitake, and oyster can grab substantial amounts of water that prolongs cooking and makes it harder for them to brown.
In fact, when we weighed batches of white, cremini, portobello, shiitake, oyster, and maitake mushrooms before and after submerging them in water for 1 minute, the mushrooms without exposed gills retained almost no water, while those with them soaked up as much as 25 percent of their weight in liquid.
It’s a good idea to thoroughly wash all foraged specimens—even those with exposed gills—to rid them of bugs, bark, and grit.
Using a salad spinner to submerge mushrooms and then spin them dry is the most efficient way to rid them of any debris and any moisture still clinging to them after cleaning.
Place mushrooms in the spinner basket set inside the outer bowl. Fill the bowl with enough water to thoroughly soak mushrooms. Swish them around with your hands.
Lift the basket from the bowl and allow water to drain away. Pour off water in the bowl and repeat the process of soaking and draining until no grit remains in the bowl.
Replace the basket in the bowl and spin the mushrooms until water collects in the bowl. If there is a lot of water, empty the bowl and continue to spin. Note: Do not spin delicate varieties; pat them dry with paper towels instead.