Last Updated July 22nd, 2021
One of the biggest complaints about (black) Wood ear mushrooms (Auricularia auricula-judae) I hear is that they smell horrible. In fact, Wood-ears do not have any obvious smell of their own, and the pungent, nitric acid like smell is most likely from sulfur dioxide, a chemical commonly used to preserve dried fruits and other dried plant food.
Although the pungent smell of sulfur dioxide coming from a packaged food would be quite concerning to most of us, the good news is that we can get rid of most of it quite easily by washing the wood ear mushrooms, since sulfur dioxide is readily soluble in warm water. Unlike with dried fruits, spices or other preserved food, we can wash wood ears thoroughly without losing any of the qualities for which wood-ears mushrooms are loved for.
If I have to bring the wood ear mushrooms quite close to my nose to detect the smell, I just deal with the issue when I actually need to use them for a recipe. Wash them in a large bowl filled with warm water, then change the water a couple of times. Usually this is all that is needed to get rid of the smell. Do a sniff test to make sure, then soak them as usual to rehydrate.
However, if the pungent smell is overwhelming upon opening the package, more cautions are definitely called for, as this concerning level of sulfur dioxide could be an indication of poorer quality overall. Soak a few wood ears from the pack and observe. If the wood ear mushrooms exhibit all the good quality characteristics (except the smell), I would consider them worth rescuing. To prevent the smell from lingering in your pantry, I suggest dealing with the whole pack straightaway. Wash the wood ear in a large container of warm water and change the water frequently until the smell is gone completely. If it is a big pack, divide the mushrooms into smaller batches, since the wood-ears will swell up while you are washing them, and the volume might become quite unmanageable with a big pack. Pat dry the clean wood ears with a clean towel, then spread them out on a wire rack and leave in a cool and well-ventilated place until they are dry completely. Now you have a safe and clean batch ready to go. When you need them for a recipe, just soak to rehydrate, or drop them into soups straightaway!