So, what's a mushroom enthusiast to do? The truth is, most mushrooms don't need to be washed at all. In fact, many experts agree that a quick brush with a soft-bristled brush is all you need to remove any loose dirt or debris. But, if you're dealing with particularly gritty or dirty mushrooms, a swift rinse under cold water might be in order.
But be warned: over-washing can be a real mushroom killer. You see, mushrooms are like sponges - they absorb water like crazy, which can make them soggy and unappetizing. So, if you do decide to wash them, make sure to pat them dry with a paper towel immediately afterwards to remove any excess moisture.
And, let's not forget about the myth that mushrooms absorb all the water they're washed in, making them incredibly heavy. While it's true that mushrooms do absorb some water, it's not quite as dramatic as some people make it out to be. In fact, a study found that mushrooms only absorb about 5-10% of their weight in water - hardly enough to make a huge difference in your dish.
The Best Way To Wash Mushrooms Before Cooking Them