Rehydrating Dried Mushrooms
Dried shiitake mushrooms, wood ear, bamboo fungus, and other dried mushrooms each call for their own rehydration approach — done right, it restores their texture to the fullest and preserves and releases their savory flavor compounds.
Why It Works
Dried mushrooms shrink and dehydrate at the cellular level during sun-drying or dehydrating. Rehydrating them is essentially a matter of letting water penetrate back into the cells to restore their original structure and springy texture. At the same time, savory amino acids and nucleotides dissolve out into the soaking water, forming a naturally flavorful liquid.
Steps
- Cover the dried mushrooms with cold or lukewarm water (no hotter than 40°C/104°F) and let them sit, covered. 2. Shiitake mushrooms need 1–2 hours; denser varieties like wood ear and white fungus (snow fungus) need 2–4 hours or longer. 3. After soaking, trim off any tough stem ends, and thoroughly clean the base of wood ear and white fungus, where sand tends to hide. 4. Once the soaking liquid settles clear, it can be strained and saved as a soup base.
Key Points
Avoid quick-soaking in boiling water — high heat damages the mushrooms' cell structure, leaving them tough and causing rapid loss of flavor. Under-soaking leaves them soft outside but hard inside; check by breaking open a cap to see if it has softened all the way through.
Common Questions
Never soak wood ear mushrooms for more than 24 hours or leave them soaking at room temperature overnight — this encourages bacterial growth and toxin production. It's best to soak them in the refrigerator or shorten the soaking time and cook them promptly.
Tips
If you're in a hurry, warm water with a little added sugar can speed up softening — the sugar helps the cells absorb water and swell faster. The flavor will be slightly less good than a slow soak in cold water, though, so when time allows, a gentle cold-water soak is still the better choice.
