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Smell

Earthy

Earthy — mushrooms tagged «Earthy»

A smell of "damp earth", a "musty cellar", a "potato pit" or "mold" is one of the most common odors among macromycetes. For a mycologist it is a serious red flag that calls for double caution when identifying a mushroom.

1 species in the database.

Geosmin and mushrooms that smell of earth

The chemical basis of the earthy smell is most often geosmin, an organic compound produced by certain microorganisms (actinomycetes) in the soil. But many mushrooms have learned to make it themselves.

M.Ya. Zerova in «Key to the Fungi of Ukraine» often uses the terms "smell of dust", "smell of radish with soil" or "smell of damp" when describing mushrooms that don't belong in your basket.

David Arora in «Mushrooms Demystified» considers the earthy smell the main diagnostic feature of several families, most of which are toxic:

1. Fibrecaps (Inocybe): A huge genus of small and medium mushrooms with conical caps. Most of them contain the dangerous toxin muscarine (even more than the fly agaric). Practically all fibrecaps have a distinct, sometimes even stifling smell of damp, moldy earth (spermatic or earthy).

2. Webcaps (Cortinarius): The largest genus of mushrooms. Some species smell of radish or raw potato, a variation of the earthy smell. Among them are deadly poisonous species.

3. Dapperlings (Lepiota): These small parasol-like mushrooms (many of them deadly poisonous) also often have an intense earthy or "dusty" aroma.

Roger Phillips notes that an earthy smell is rare among first-class edible mushrooms. Most culinary prized species smell "pleasantly mushroomy", of flour, fruit or nuts, while an earthy aroma is more often associated with toadstools.

Questions and answers

Why does the forest smell of mushrooms and earth after rain?
This phenomenon is called petrichor. When raindrops hit dry soil, they release microscopic bubbles into the air that contain geosmin (a substance produced by soil bacteria and fungal mycelium). That is what creates the classic earthy, mushroomy smell of the forest.
Are there edible mushrooms with an earthy smell?
Yes, but not many. For example, some edible webcaps (such as Cortinarius caperatus, the gypsy mushroom) can have a faint earthy, dusty smell. Truffles are also often described as having an aroma with powerful earthy notes. But for gilled mushrooms (unless you are an expert), a strong earthy smell is a reason to leave the mushroom in the forest.
How do you tell an earthy smell from an ordinary "mushroomy" one?
A "pleasant mushroomy" smell is sweetish and appetizing (like a fresh supermarket button mushroom or a porcini). An "earthy" smell is heavy, damp, stale and unappetizing, reminiscent of the air in a damp old cellar.
How do you get rid of an earthy smell if the mushroom is edible?
If you know for certain that you have picked an edible mushroom with a faint earthy smell, you can boil it for 10 minutes in salted water. Most of the volatile compounds responsible for the damp smell will break down or boil off, and the taste will become neutral.

Sources

  1. 1.Зерова М.Я. та ін. Визначник грибів України. 1979
  2. 2.Roger Phillips. Mushrooms (Roger Phillips)
  3. 3.David Arora. Mushrooms Demystified
  4. 4.Index Fungorum