Odorless

Why some mushrooms don't smell

An absence of smell means the mycelium and fruiting body don't produce specific volatile organic compounds (esters, alcohols, aldehydes) in high enough concentrations for the human nose to pick up. In the «Key to the Fungi of Ukraine», M.Ya. Zerova often uses the terms "smell not distinct" or "absent" for many families, including a large number of brittlegills (Russula) and some polypores.

David Arora warns in «Mushrooms Demystified» that a lack of smell can be misleading. Sometimes a mushroom really has no smell, and sometimes conditions simply don't let you detect it. The strength of the aroma depends on:

1. Temperature: In cold weather or after frost, volatile compounds barely evaporate. Even very fragrant mushrooms will seem "odorless".

2. Moisture: Dried-out or, on the contrary, completely waterlogged mushrooms lose their characteristic aroma.

3. Age: Old specimens often lose their original aromas and pick up a smell of rot instead (which is a different marker altogether).

How to make up for a missing smell when identifying

When there's no smell (as in some milk caps or brittlegills), Roger Phillips advises switching your attention to other chemical and physical features:

- Taste: Pinch off a tiny piece of flesh — but only once the genus is identified (for example, a brittlegill or a milk cap) — chew it on the tip of your tongue, spit it out and rinse your mouth. Never taste whitish or greenish gilled mushrooms with a ring or a sac (volva) at the base: deadly toxins have no telltale smell or taste, so these tests can't reveal them. The taste can be burning or bitter even in a mushroom with no smell.

- Color change: Make a cut or a scratch on the hymenophore.

- Spore print color: Leave the cap on a sheet of paper overnight.