Smell

Pleasant, mushroomy

When a mycological guide says "smell pleasant, mushroomy" (or just "mushroomy"), it means exactly that classic, rich, earthy-nutty aroma you notice when you open a pack of dried porcini or slice fresh button mushrooms from the supermarket. It is the benchmark against which we subconsciously judge all other mushrooms.

12 species in the database.

The chemistry of the "real" mushroom smell

Chemists cracked the secret of this signature aroma long ago. The classic mushroom smell comes from the molecule 1-octen-3-ol (it is even called "mushroom alcohol"). M.Ya. Zerova notes that this alcohol is produced in large quantities during the oxidation of linoleic acid when the mushroom's cells are damaged (for example, when cut or chewed by insects).

Roger Phillips in his guide «Mushrooms» describes the most striking carriers of this aroma:

1. Porcini (Boletus edulis): Fresh porcini smell very delicately, but during fermentation and drying the concentration of 1-octen-3-ol and other compounds rises dozens of times. Dried porcini have the most powerful "pleasant mushroomy" smell in the world.

2. Button mushroom (Agaricus bisporus): This is the very same store-bought mushroom. Its fresh, sweetish-earthy aroma is the perfect example of the basic mushroom smell.

3. Bay bolete and slippery jacks: They have a mild, classic mushroom aroma with nothing else mixed in.

Why it matters for identification

David Arora emphasizes that a "mushroomy smell" is often a sign that a mushroom belongs to a safe edible group (boletes or true Agaricus). However, this smell is so basic across the whole kingdom of macromycetes that relying on it alone is dangerous.

Even some poisonous species (especially amanitas when young) can have a completely standard, "store-bought" mushroom smell.

Questions and answers

Why do dried porcini smell stronger than fresh ones?

During slow drying, a complex enzymatic reaction takes place in the cells of the porcini. Proteins and amino acids break down, forming new aromatic compounds. On top of that, water evaporates, and the concentration of aromatic substances (especially 1-octen-3-ol) reaches its maximum. That is why a pinch of dried porcini smells stronger than a basket of fresh ones.

Can the mushroom smell be reproduced artificially?

Yes. 1-octen-3-ol has long been synthesized in chemical plants. The food industry uses it to make "mushroom" bouillon cubes, mushroom-flavored chips and sauces.

Do the poisonous lookalikes of porcini have the same smell?

The bitter bolete (Tylopilus felleus), often mistaken for porcini, has a faint mushroom smell (sometimes with a musty note). Its main difference is not the smell but its unbearably bitter taste and pink hymenophore.

Sources

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