Can you judge the quality of dried mushrooms just by looking at the package?
While developing our recipe for Daube Provençal, we noticed disturbing differences in quality from one package of dried cèpes to another. More commonly known by their Italian name, porcini, dried cèpes should be large and thick (top photo) and either tan or brown—not black. Avoid packages with lots of dust and crumbled bits (middle photo) and keep an eye out for small pinholes, telltale signs that worms got to the mushrooms (bottom photo). Eyeballing is good, but smelling the mushrooms (especially if sold loose) is also helpful to judge quality. Purchase dried cèpes with an earthy (not musty or stale) aroma; mushrooms with no aroma at all are likely to have little or no flavor.
Packages of "wild mushroom mix," found in some stores, should not be substituted for cèpes. Although these mixes sometimes include cèpes, they also often include lesser-quality mushrooms whose flavor profiles may not suit the dish.