Making dehydrated mushrooms with a dehydrator is a great way to preserve an abundance of foraged mushrooms. You can also use this method to make sure that the store-bought mushrooms in your refrigerator don't spoil before you get around to eating them.
Most mushrooms dry beautifully, not only retaining but even gaining flavor in the process. When rehydrated in hot water, their texture is almost identical to fresh mushrooms.
Dried mushrooms can be stored for at least a year.
How to Make Dehydrated Mushrooms with a Dehydrator
1. Clean the Mushrooms - Wash and Scrub
First, you will need to clean the mushrooms. Contrary to culinary myth, raw mushrooms do not actually soak up lots of water. You don't have to skip washing them and get all of the dirt off with a brush.
Go ahead and wash them in water, scrubbing with a vegetable or mushroom brush as necessary. This will make your prep much easier, especially with species that have lots of nooks and crannies, such as maitake.
Depending on what seems easiest for the shape of the mushrooms, either clean them whole and then slice them, or vice versa. It is acceptable to slice them first and then clean them if that seems easiest.
2. Slice the Mushrooms
Slice the mushrooms between 1/4 to 1/2-inch thick.
The thicker the slices, the longer they will take to dry, so consider this when you are slicing. Your choice may depend on how you plan to use them later. If you want thicker slices in your dishes, slice them thicker, and vice versa.
3. Arrange the Sliced Mushrooms on the Dehydrator Trays
Arrange the cleaned, sliced mushrooms on the dehydrator trays, making sure that none of the pieces touch or overlap.
This will allow the best airflow around them and they will dry faster and more evenly. If they touch or overlap, some areas may still retain some moisture.
4. Dry the Slices in the Dehydrator
Dry the sliced mushrooms at 110F/43C until the pieces are crispy dry. This will take 4 to 6 hours for 1/4-inch slices, up to 8 hours for thicker slices.
5. Cool the Dried Mushrooms
Allow the dried mushrooms to cool completely before transferring them to glass jars.
6. Store the Dehydrated Mushrooms in Glass Jars
Transfer the cooled dried mushrooms to glass jars. Cover tightly with lids. Label the jar with its contents, including the type of mushroom and the date they were dried. Store the jars away from direct light or heat.
Rehydrating Your Dried Mushrooms
To use dehydrated mushrooms, pour boiling water over them in a heat-proof bowl. Let them soak for 20 to 30 minutes. Drain them, reserving the richly-flavored soaking liquid for soup stocks and sauces. Use the rehydrated mushrooms as you would fresh mushrooms.