Skip to content

Never eat a wild mushroom identified from a website. This one helps you rule things out. It cannot rule anything in.

Mr Mushroom
← All cultivated species

Button and field

Button, cremini and portobello

Agaricus bisporus

Never eat a wild-foraged mushroom you identified from a website, this one included. Wild mushroom misidentification can be fatal, and no page can rule a specimen IN. This reference is about cultivated and shop-bought mushrooms only: species you buy, or grow from bought spawn, where there is nothing to identify. To identify anything wild, consult a qualified local expert holding the actual specimen, never a description on a screen.

Also sold as

  • White button
  • Chestnut mushroom
  • Cremini
  • Baby bella
  • Portobello
  • Swiss brown

In the kitchen

Flavour

Mild and earthy when white, deeper and more savoury as it browns and matures. The same mushroom concentrates in flavour with age.

Texture

Firm and watery raw; the large portobello turns meaty and dense once the water is cooked out of it.

In the kitchen

The default supermarket mushroom. White buttons for slicing raw into salads or quick frying; cremini for stews and sauces; the mature portobello grilled or roasted whole as a burger or steak. All three are one species, so they cook alike and only differ in age and strain.

How it is cultivated

Substrate

Composted straw and manure, cased with a peat and lime layer that triggers fruiting. This composting and casing is why it is a commercial rather than a home crop.

Fruiting temperature

14-18°C (57-64°F)

Humidity

85-90% relative humidity

How it is grown

Composted substrate with a casing layer

Time to first harvest

Roughly 3 to 5 weeks after the casing goes on, following a longer spawn run

How much, how long

Two or three flushes about a week apart

Difficulty at home

Advanced. The composting and casing steps are what put this out of reach of a beginner, not the growing itself.

What is worth knowing about it

Button, cremini and portobello are the same fungus, Agaricus bisporus, at different ages and strains: white and brown immature forms are the button and the cremini, and the fully opened brown form is the portobello. Knowing this is most of what a shopper needs, because it explains why the price gap rarely matches any real difference on the plate.

Sources

  • Wikipedia, Agaricus bisporus
  • Stamets, Growing Gourmet and Medicinal Mushrooms