Not worth eating
Chaga
Inonotus obliquus
The character that does the work
Black cracked charcoal-like mass on a LIVING BIRCH, rusty orange inside.
The specimen sheet, in examination order
01Cap
An irregular black cracked mass 10 to 40 cm across, like charcoal or burnt wood, bursting out of the trunk.
02Underside
None visible. The sterile conk is what people harvest; the fertile surface forms under the bark and is rarely seen.
03Stem, and the base
None.
04Flesh, cut
Rusty orange-brown inside, corky and hard.
05Spore print
06Where it grows
On living birch, almost exclusively, in cold northern forests.
When to look
Typically Jan to Dec in the northern hemisphere. Fruiting swings by weeks with rainfall and by a month or more with latitude, so this is when to look rather than when it will be there.
Northern Europe, Russia, northern North America.
What is worth knowing about it
Two problems travel with chaga and neither is usually mentioned. It is being harvested faster than it grows, since a conk takes many years to form and killing the tree ends the supply. And it is very high in oxalates, with documented cases of kidney damage in heavy long-term users, which makes it a poor choice for anyone with any kidney concern at all.
Confused with
- Burls and cankers, which are wood rather than fungus
- Black knot
In the kitchen
Not a food. Simmered long and slow as a tea, never boiled hard.
The techniques, and why they workSold as a supplement
The weakest human evidence of the group, combined with the clearest documented harm, which is an unusual and unflattering combination.
The claims, graded by what the evidence actually isThis page tells you what to check. It does not tell you the mushroom in your hand is that species, and it cannot. If you are not certain, do not eat it. If you have already eaten something and feel unwell, contact a poison centre and keep an uncooked specimen.
Others in this group