How to Identify and Pick Oyster Mushrooms

Oyster mushrooms, or Pleurotus Ostreatus as they are called in Latin, are mushrooms you can pick at any time of the year. They are are not dependent on seasonal changes but rather react to weather changes. I’ve picked them in winter after a frost, I’ve picked them in May/June after a long wet spell and I’ve also picked them in Autumn after the first colder period. To properly understand when it is good to pick oyster mushrooms you will need to start paying attention to the weather. This guide on how to identify and pick oyster mushrooms will hopefully help you understand the basics of oyster mushroom hunting.

Before I get to explain how to harvest oyster mushrooms I want to mention the basics about the species. They are an important part of keeping forests tidy. Oyster mushrooms are a saprotroph, meaning that they serve as a decomposer of dead woody material. They are not a parasite but rather a friendly janitor of the forest. They love growing on deciduous trees, which means any type of tree that has leaves. They especially love beech trees that have fallen over or have become ill but will never directly kill a tree. I mostly find mine on decaying trees that fell over a couple of years ago.

Mushroom Etiquette

Normally I’d write a long part about mushroom etiquette when it comes to harvesting mushrooms, but with oysters, this changes quite a bit. Whereas ground growing mushrooms are quite easy to disturb it will take a lot more to destroy a colony of oysters. As always, be respectful to the area you pick in and make sure to cut the mushrooms off the trees with a knife. If you rip the mushroom off it will hurt the colony, but to some extent, the hardiness of this mushroom makes it a perfect mushroom to harvest and if you are lucky you might catch a blue spiderman in the act of oyster hunting. Since I am not a professional paparazzi these were taken with my cellphone but you can still see that treading lightly when looking around trees is very important to this specimen. 

Joking aside you should definitely be respectful of your surroundings. Don’t break shrubbery or damage trees around the mushrooms and remember to tread carefully. There are little creatures living everywhere that would like to keep their home the way it is. 

Spotting oyster mushrooms

When foraging for oyster mushrooms you should look for old, open, leafy forests with beech and oak. Generally, I pay attention to trees that have fallen over or look like they are dying as these are the perfect breeding grounds for oyster mushrooms. Make sure to check the underside of toppled trees as the oyster mushroom prefers to grow in the shade. Follow the below pointers to increase your chances of finding oyster mushrooms.

• The oyster mushroom is a widely spread mushroom that grows on dead or dying trees. Look for toppled beech trees or trees that look dead from a distance.
• They grow at any time during the year in temperate climates – however, try to go out after a weather change like the first hot weekend of the spring or the first frost of the autumn.
• Oyster mushrooms grow incredibly quickly. You have to find them when they are quite young or else you risk the mushrooms getting leathery and tasting off.
• Pick only the younger specimens – the older ones are perfect for spreading the spores and will not taste good anyway. 
• Once you spotted one oyster mushroom you will likely find several kilos (or pounds) in that one location. They grow in huge numbers if the conditions are right.

Identifying an oyster mushroom

The reason why this mushroom is called an oyster mushroom is that its appearance resembles the clam. They have a broad fan-shaped cap spanning 5-25 cm and come in a variety of colours. I’ve found them in grey, white, dusky pink and tan but the main identifier is that the gills are always white or cream coloured. They have a nice almondy smell when young and have no poisonous lookalikes in Europe.

American readers should be wary of the western jack o’ lantern which is a poisonous, yellow lookalike. I tend to stay away from an oyster with a yellow colour as this is bound to be the jack o’ lantern. Another poisonous lookalike is the ghost mushroom (Omphalotus Nidiformis) it can be found in Japan and Australia so become familiar with this mushroom if you live in those countries. 

The below picture shows how the oyster mushroom grows on toppled beech trees. This clump alone weighs about 0.5 kilos. You can easily be in luck and end up filling your basket in 10 minutes when foraging for these mushrooms.

My favourite aspect of foraging for oyster mushrooms is the fact that there is little to not cleaning required. They generally grow in places that have little to no forest litter and hence come off perfectly pristine. The only thing you might have to do is cut off the occasional snail damage. Below you can see one of the smaller clusters we found while my dad was visiting. I asked him to hold it so you can see how large even smaller clusters are in comparison to a man’s hand.

Preserving oyster mushrooms

Oyster mushrooms are pretty easy to preserve. I generally dehydrate them like it is done in Asia and it works really well for woks. When you want to rehydrate them just soak them in cold water for a few hours. If you are on the inpatient side or in a hurry then you can also pour boiling water over them and let them steep for about 10 minutes and they’ll be ready to use.

They can also be blanched and frozen or pickled. However, I found that dehydrating is the best way to preserve them, and it is also the most common way of doing it in areas where the mushroom is eaten a lot. Dehydrated mushrooms can be used in any dish but they can also be used as seasoning if you grind them up into a powder. 

I hope you enjoyed my guide on how to identify and pick oyster mushrooms, it is a fun and easy mushroom to pick out of the “normal” mushroom season. For more guides on how to pick our most common and delicious mushrooms – click on the pictures below.