All About Mushrooms

Sometimes! Mushrooms with exposed gills (such as portobello and shiitake) absorb lots of water. Avoid washing these varieties. Instead, simply brush off any dirt with a pastry brush or paper towel. Varieties that don’t contain exposed gills don't soak up much water at all, so it’s fine to wash them before cutting them (exposed flesh will absorb water like a sponge). Note that most cultivated mushrooms are very clean and don’t require washing in the first place.

Unfortunately, not long. Due to their high moisture content, fresh mushrooms are very perishable. Properly stored, however, they can last at least a week.

A slimy film on the cap and stem, mushy texture, and dark discoloration are the classic indicators of spoiled mushrooms. If you have white button mushrooms that are looking slightly old and blemished, don’t discard them—sometimes they taste even better this way! Do not, however, use mushrooms that smell fermented or look slimy.

Neither plant nor animal, mushrooms are fungi that grow on the forest floor. There are around 1,000 edible varieties, but only about 20 are commercially cultivated. The mushrooms we buy in the supermarket are grown under highly controlled conditions on mushroom farms.

Mushroom cell walls are made of a uniquely resilient, heat-stable polymer called chitin. This substance (which is also found in the exoskeletons of crustaceans such as shrimp and lobster) enables mushrooms to maintain their pleasantly firm, chewy texture over a wide range of cooking times.