Edibility and Poisoning

An overview of mushroom edibility and poisoning

Most wild mushroomers are looking for edibles. Some are looking for hallucinogens, and we don’t have help with that here; but we do provide support in looking for edibles. The best way to start out (and this is how most of us do it) is by learning a few distinctive mushrooms to look for. When you get comfortable with those you start looking to branch out, buy a book or two, and start becoming aware of just how much is out there. There are a tremendous variety of mushrooms in North America – we have about 200 named species of birds and about 11,000 named species of mushrooms, with more being discovered each year. So if you try to just plunge in and learn everything at once you’ll get swamped. We have other articles for coping with mushroom diversity; this one is about the diversity of mushroom edibility.

How can you tell if a mushroom is edible?

There are no general guidelines for mushroom edibility. There are many folk rules such as

If it turns rice red, it’s safe to eat.
If you cook it with a silver coin and the coin doesn’t turn black, it’s safe.
Don’t eat anything that grows on wood.
Only eat mushrooms that grow on wood.
Don’t eat white mushrooms.

None of these work. You have to identify what you’ve found in order to know whether it’s edible or not. There are some groups that are generally toxic or edible, but you have to have your mushroom’s identity pretty narrowed down for that sort of “family reputation” to come into play.

How many mushrooms are poisonous?

There aren’t that many deadly mushrooms, but there are a great many that will make your digestive tract eject anything in it, at maximum velocity and discomfort, from whichever end is closest. And your gut will continue to attempt doing this long after all its contents have actually been expelled. We say, “It won’t kill you, but it’ll make you wish it had.” If you are trying to convince small children not to randomly sample mushrooms, mentioning this can be a better strategy than talking about the deadly ones, as kids have a much better grasp of what it’s like to throw up than they do of death.
Almost all the fatalities in North America are caused by three taxa: two types of Amanitas (95% of all fatalities), and LBMs (little brown mushrooms). This does not mean that you are safe from dying if you avoid those three groups! New deadly mushrooms are discovered every few years.

Okay, so how many mushrooms are edible?

Well, that depends what you mean by edible. Some wild mushrooms are downright wonderful. They have flavors that you can’t get anywhere else. Many mushrooms you find will be edible but not be worth eating. They won’t be poisonous, but (like maple leaves, for example) there’s just no real reason to eat them. Sure, if you cover them with a savory sauce and crisp them nicely I’m sure they can be quite tasty (again, like maple leaves) but other than the thrill of gathering your own food from the wild, there’s no reason not to use an ingredient with some flavor of its own instead. Where to draw the line as to what’s worth gathering is up to you.
Also, wild mushrooms often taste quite different to different people. You will undoubtedly find some that are listed in the books as not terribly good but you really like. Enjoy them! Conversely, you may not like some of the ones that are really popular. Don’t be embarrassed. There’s no reason to keep eating something that you don’t enjoy.
Most of our cultivated plants and animals have had their evolution driven by humans for millennia; and one of the features they’ve been selected for is to taste similar to most people. Even so, there are still people who don’t like this or that cultivated food. But wild mushrooms, which haven’t had any pressure at all to have everyone like them, are a lot more variable. This is another reason to make friends with other mushroom hunters: so you can trade the ones that you don’t like for the ones that they don’t like!

Are there other issues with edibility?

Why, yes! If there’s some chemical in the ground that the fungus doesn’t like, it can’t just walk away from it the way we can to avoid an oil spill. Instead, what it does is pump those chemicals up into its mushrooms, so that some nice animal can eat the mushroom and carry the chemicals away. You don’t want to be that animal.
Lawn chemicals – fertilizers, weed killers, etc. – are the most common sort of chemical you’re likely to be at risk for. Fungi don’t like these sorts of chemicals, and seem to exert themselves quite strongly to get rid of them. Cemeteries, golf courses, and other places with well-manicured lawns are unhealthy places to gather mushrooms.
Also, the forest (or even the lawn) is a wild place where there are plenty of other competitors who want to eat that mushroom, or use it as a platform to start eating you. There are plenty of bacteria out there, and animals pooping spreads their worms and other parasites. Always cook your mushrooms well, and make sure they are in good condition. It’s a thrill to find your food in the wild; but if you wouldn’t eat something in this condition from the store, don’t eat it just because you found it yourself – rotten food is rotten food.

In short:

Wild mushrooms can be delicious and delightful to eat, but care is necessary.
To know which mushrooms to eat; you have to identify them; general rules about colors, color changes, or where they grow are no good.
If it’s in bad condition, or growing in an unsafe place, don’t eat it.
There are lots of different mushrooms out there. Start by trying just a few and learn more of them gradually.
If you do things right, you will have taste treats that you can’t get any other way!