I had free time today. Actually I was busy, but working at home. I was also cooking mushrooms. So I experimented too.
I held back one button mushroom (unwashed) and weighed it. 24g. I then soaked it for 5 minutes and reweighed it after wiping off surface moisture with a kitchen towel. 25g. Then I kept going. I have no idea how much any variations are due to remaining surface moisture, but the differences are so small as to be negligible.
0 minutes - 24g
5 minutes - 25g
10 minutes - 25g
30 minutes - 26g
1 hour - 28g
2 hours - 28g
3 hours - 28g
Then I got bored and ate it - raw. It tasted like a mushroom.
Given that washing the damn thing in the first place would only take seconds and probably result in no weight difference, I'm going to continue washing them.
I'll repeat this with other mushrooms (oyster, shiitake etc) when I have time.
