Bay bolete vs. porcini: what's the difference?

At the market you'll often hear: “Porcini, get your porcini.” And in the basket, next to the classic boletes, lie mushrooms with dark chestnut caps and a slightly different character. This is the bay bolete (Boletus badius, in our catalog the bay bolete), a close relative of porcini that is often sold under the same name.

It's not a scam or a mistake: the bay bolete really is tasty and prized. But for a practical forager it's useful to know that this is a separate species with its own key feature. Let's sort it out once and for all.

Is the bay bolete a porcini or not

The short answer: no, they're different species, though close relatives. True porcini (ceps) have white flesh that doesn't change color when cut. The bay bolete also belongs to the bolete family, but it's been split off as a different species, and its flesh turns blue when cut.

So why are they confused? Because both are tasty and aromatic, with a spongy underside to the cap and a thick stem. On the table the difference is barely noticeable, so in cooking they're often treated as equals. But in the forest it pays to tell them apart, so you can read your finds with confidence.

The main difference: bluing when cut

Remember one thing, and you'll never mix up these mushrooms. Press a finger on the tubular underside of the cap or cut the mushroom.

• Porcini. The flesh and pores stay white; the color doesn't change. This is a constant feature of the whole porcini group.
• Bay bolete. Where you press, the pores quickly turn blue, sometimes almost blue-green. The cut flesh turns blue too.

This bluing is completely harmless: the bay bolete is edible and tasty. But it's exactly what clearly sets it apart from true porcini. If a mushroom turns blue, it's definitely not a porcini, though in this case there's nothing to worry about.

Other differences worth a look

Besides bluing, there are a few more details that help tell the species apart.

• Cap. On the bay bolete it's evenly dark chestnut, smooth, and greasy in wet weather. On porcini the tone is warmer, from hazel to chestnut, depending on the variety.
• Stem. The bay bolete's stem is slender and brownish, with no distinct net pattern. On porcini it's thick and barrel-shaped, with a pale net pattern.
• Pores. On porcini they're white or yellow; on the bay bolete they're greenish yellow and turn blue when touched.

No net pattern on the stem plus bluing give you a reliable pair of features. To see the difference clearly, check out our side-by-side comparison of porcini and the bay bolete.

Where and when they overlap

The bay bolete favors conifer and mixed forests, so its most frequent neighbor is the pine bolete.

Look for it in the same places as porcini:

• old mossy pine forests;
• patches of mixed forest where pine grows alongside birch;
• sunny edges of conifer forest and sun-warmed sandy hills.

The bay bolete's season is later and longer: it fruits from July into late autumn, sometimes right up to the first frosts. The best time to go out is two or three days after a warm rain. An easy way to keep track of these windows is our mushroom radar: it shows when moisture and warmth line up just right for boletes to appear.

Is the bay bolete worth picking

Absolutely. The bay bolete is tasty, aromatic and great for drying, pickling and frying. Many foragers value it as highly as porcini, and to them the bluing when cut isn't a flaw, just a trait of the species.

The main thing is not to confuse the harmless bluing of the bay bolete with the bluing of dangerous boletes, such as the lurid bolete. In doubtful cases, go by the color of the pores and stem, and when you're not sure, better leave the mushroom in the forest.

Sources

• “Field Guide to the Fungi of Ukraine” (Kyiv, Naukova Dumka publishing house).
• Boletus badius in GBIF, the global biodiversity database.
• Imleria badia in MycoBank, the international fungal nomenclature database.
• Imleria badia on Wikipedia.