The slower soaking of mushrooms in room temperature water yields a much better texture than a rushed soak in warm or hot water. In addition, the use of hot water leaches out more flavor from inside the mushrooms. The ideal method for rehydration of dried fungi is to place them in a narrow container as opposed to a wide bowl. This will enable you to use less water and still cover the fungi. Use a container that has a “buddy,” another container that fits inside that can be used to hold down the mushrooms under water (they tend to float when dry).