Thank you for bringing me out of the mushroom dark ages and dispelling the myth that getting mushrooms wet is a no-no. I am a liberated woman now. No more wiping, no more brushing, no more scrubbing to get those pesky little pieces of dirt of my fungi!
I have to say that I was a bit skeptical at first. After a little googling, I found out about Alton Brown's experiment of soaking mushrooms in water and weighting them afterwards to find out that they only absorbed a trivial amount of water. But I had two problems with this experiment. Alton only used button mushrooms and I was wondering whether his conclusions would still hold for other types of mushrooms. After 10 minutes of soaking, 4 oz of mushrooms absorbed around 1 teaspoon of water. This sounds trivial, but I wouldn't consider putting 1 teaspoons of water on my steak if I wanted it to brown, so why would I allow any moisture touch my mushrooms.Since the sweat-and-sauté method resulted in a large release of mushroom juices, an extra teaspoon of absorbed water won't make a dent. But what about roasting? The whole objective there is to get mushrooms nicely crisp around the edges. Will that work with damp mushrooms?
There was only one way to find out. I bought some portabellas and oysters today and split them into two batches. I washed and thoroughly dried the first batch and brushed the dirt off the second batch with my usual toothbrush method. Portabellas got almost completely back to their pre-wash condition once I was done drying them. But the oysters got pretty soaked. They are very delicate and some water got stuck between their gills, which made complete drying almost impossible.
I placed the mushrooms on a large cookie sheet side by side. Drizzled with oil and sprinkle with salt, then roasted at 425F. The only difference between washed ones and brushed ones was the cooking time. The washed mushrooms took a few extra minutes to get nice and crisp, but final result was identical between the two batches.
The pile on the right was washed and pile on the left was not washed. Why are the washed ones even crisper than the unwashed? I put them in the oven for a few extra minutes and forgot to set the timer ;)
How did they get crispy if they absorbed extra water? I'll side with Matthew's theory:
What I'm visualizing happening is: as soon as the mushroom warms up, it's going to release tons of water. The surface browns after the water is evaporated. So the surface is going to get temporarily slimy in the oven anyway.My Mom is probably laughing reading this post. I am sure she'll say, "I told you so :)" In Russia, mushrooms are always washed, and she's been giving me funny looks when watching me attempt to clean them without water. So, kids, listen to your Moms (unless they tell you to wash chicken ;)
* Matthew Amster-Burton is a great food writer. Check out his Unexplained Bacon column on Culinate and his blog.