What to Do with the Rehydration Water from Dried Mushrooms?
The rehydration water from dried mushrooms is a concentrate of mushroom flavors. It would be a shame to miss out on it.
The first step is to filter it (in a coffee filter, or through a paper towel if you don't have a fine sieve).
Once filtered, you can use it as it is to cook pasta, rice, or to moisten a risotto.
Alternatively, you can reduce it by half to further concentrate the flavors and mix it into your sauces, creams, etc.
Once reduced, if you don't need it right away, you can pour it into ice cube trays and put it in the freezer.
This way, you can use it whenever you want, like a bouillon cube!