Gyromitra esculenta is called the brain mushroom for a reason — its wrinkled cap looks a lot like the cerebral cortex we all know from anatomy books. It’s quite different from the umbrella cap and gills we see in most edible mushrooms. Still, untrained eyes may mistake it for a morel, which could be a fatal mistake. As little as 400 grams of this mushroom can kill.
The water-soluble chemical gyromitrin is to blame — the brain mushroom has plenty of it. Gyromitrin poisoning begins with a host of gastroinstestinal symptoms — nausea, vomiting, and diarrhea. Neurological symptoms follow, including dizziness, tremor, headaches, and fever. After a day or so, seizures and coma can kick in. On top of its toxicity, the mushroom also contains carcinogens.
But the fascinating thing about Gyromitra esculenta is that it’s not deadly for everyone. People who’ve eaten it from the same dish have suffered terribly — even died — while others suffered hardly any symptoms. Although the toxicity of this mushroom is well proven, it seems to work using the mechanisms of allergic reactions, hence different effects for different people.
There’s more to it than that, though. If the mushrooms are dried in the open air for at least 10 days, or if they are boiled twice in copious amounts of water for five minutes and rinsed, gyromitrin loses most of its punch. Traces of it may still remain, though, making the brain mushroom a food good only for the courageous. (And yet, people describe the brain mushroom as “mild-flavored.”)
In Germany, Switzerland, and Spain, the authorities have banned the brain mushroom. In Poland it’s also banned — it’s estimated that the brain mushrooms is responsible for most post-WWII poisonings in Poland. In Finland it’s eaten in tonnes every year, often in an omelet or as a pie filling. Bulgarians also love it. It’s also eaten in the Western U.S. Swedish chefs even use it on live TV (and get bashed for it).
In the end, the brain mushroom is not just a dangerous delicacy, but quite a life form. The question is, would you eat it?
PS: You probably won’t find this mushroom at your local market anytime soon…