Porcini or Brown birch bolete

The cap is 7–30 cm across, round or hemispherical when young, then cushion-shaped and flattening with age. Its color ranges from light brown to dark chestnut or reddish brown depending on the light and the type of forest: darker in spruce woods, paler under pine.

The surface is dry, smooth or slightly wrinkled, and may turn a little sticky in wet weather. The margin is even or slightly wavy, and rolled under in young caps. The skin doesn’t peel.

The cap is 5–15 cm across, round or hemispherical at first, later cushion-shaped. The surface is smooth or slightly wrinkled, and dry or a little sticky in wet weather. It ranges from grayish brown to dark brown, occasionally almost black.

Underneath are tubes that come away easily from the cap flesh. They start white, then turn yellow, and in mature mushrooms become yellow-green or olive. The pores are small, round and evenly colored, and they don’t change color when pressed.

Underneath are white tubes and pores, small in young mushrooms and wider in mature ones. Pressed, the pores turn slightly brownish, but there's never any bluing: unlike in the red-capped scaber stalks, the flesh doesn't turn blue even at the stem base.

The stem is massive, 5–20 cm tall and 3–10 cm thick: bulbous or club-shaped when young, more cylindrical later. It’s whitish to light brown and covered in a distinctive white or cream net pattern, clearest near the top.

There’s no ring and no volva, and the stem base is often swollen.

The stem is 8–18 cm tall and 1.5–3 cm thick, cylindrical, and fairly long and slender for the size of the cap. It's white or grayish, densely covered in dark, fibrous scales, the hallmark of the genus Leccinum. The stem is firm and fibrous.

The flesh is dense, juicy and white, and it doesn’t change color when cut or bruised — a feature that sets porcini apart from several poisonous lookalikes. In old mushrooms it turns spongy and yellowish.

It tastes mild, nutty and slightly sweet. The flesh in the stem is denser and more fibrous than in the cap.

The flesh is firm and white. When cut it stays the same color or turns slightly pinkish, and after a few hours may go a little grayish or brownish. It darkens to gray-black only when cooked. The taste is mild and neutral, and the cap skin doesn't peel.

The smell is pleasant and gentle: mushroomy, with a light nutty note. Cooking and drying bring it out, giving it a deep, rich, woodsy character. Dried porcini are the reason cooks prize this mushroom so highly — no other dried mushroom has such a strong flavor and smell.

The smell is subtle, pleasant and typically mushroomy, and it gets stronger with cooking. Dried, the brown birch bolete takes on a rich scent that falls short of porcini but is noticeably better than most other pored mushrooms.