Should You Discard Mushroom Stems?

A mushroom stem supports the cap, and in cultivated mushrooms it has the same texture as the cap. It is a little firmer and more fibrous, but tastes the same. Stems are often discarded out of habit: the cap slices neatly, while the stem is set aside because it gets in the way of slicing. But if the mushroom will be chopped for cooking, there is not a single difference between the stem and cap; both cook in the same pan for the same amount of time. Chop the stem together with the cap for sautéing, stews, omelets, and soup.

The only part that needs trimming is the very bottom of the stem. Mushrooms grow in compost, and soil and compost residue collect at the base; if this end is dried out and dark, cut off a thin slice. Wipe the rest of the stem with a brush or damp cloth, because mushrooms absorb water easily and release it into the pan if they are washed for too long. Chop the mushroom as soon as it is cleaned, because the cut surface darkens when exposed to air. The inside of the stem should be white and firm; a darkened or spongy interior indicates that the mushroom has been sitting for a while, so discard it. Check the cap of the same mushroom as well.

To make stuffed mushrooms, twist the stems out of the caps. Do not discard the stems; chop them finely and use them as the main ingredient in the filling. Sauté them with onion and garlic, mix them with cheese, breadcrumbs, or ground meat, and fill the caps. This fills each cap with its own stem and carries the mushroom flavor into the filling. The stems release water as they sauté; if you do not cook them until the water has evaporated, the filling will make the caps wet and they will steam in the oven instead of browning. Adding a little parsley to the filling softens the strong flavor of the stems and brightens the filling.

Dried mushrooms and some wild mushrooms are different. Their stems are thick, hard, and fibrous; even when soaked, they do not soften as much as the caps and remain tough when cooked. Do not leave these stems in the dish. Remove them from the caps and add them to mushroom, meat, or vegetable stock; they give the liquid a deep, concentrated flavor, and after cooking, strain them out. Do not discard the soaking water from dried mushrooms either; separate and strain out the sediment at the bottom, then add the water to the dish. If you will not use the fibrous stems right away, collect them in the freezer and add them to your next batch of stock.

Whether a stem is edible depends on the type of mushroom; a practical way to tell is to bend it. When bent, a cultivated mushroom stem snaps crisply; that indicates an edible stem. The thick part at the base of an oyster mushroom cluster remains tough and should be cut off, while the thin stems above it can be used. A shiitake stem does not snap when bent; it flexes in fibers, so use it only in stock. In short, stems that snap are eaten, while flexible stems are added to the pot for flavor and removed at the end.