These mushrooms might sound quite familiar, as they are readily available in the supermarket aisles, often included as part of the misleading ‘wild mushrooms’ packets. However, the truly wild species can be quite variable and more often than not, they look entirely different.
In my opinion, oysters are one of the best edible mushrooms. They can reach big sizes and have a succulent meaty texture full of flavour that makes them perfect for stir fries and offer a solid vegan alternative to meat dishes.
Description and species
Oyster mushroom (Pleurotus ostreatus) is sometimes referred as Grey oyster, straw mushroom, hiratake or tamogitake. It is also known by any other name you can imagine with the word ‘oyster’ on it, due to resemblance of the fruiting body to the bivalve of the same name.
It is easily recognised by the way it grows on wood in shelf-like formations with overlapping clusters of smooth shell-like shaped caps. They are relatively large in size and come in 50 shades of grey, while other related species can also be found on yellowish and pinkish tones.
The cap is convex shaped when young and flattens out as they grow, becoming inrolled and wavy. The flesh is white and firm, becoming meatier and tougher in maturity. It has cream coloured gills and sometimes nearly-absent stem. The smell has a delicate aniseed aroma.
Its name is sometimes referred to closely related species, including Pleurotus pulmonarius or Pleurotus populinus. However, all species are edible and have no poisonous lookalikes in Europe. Nonetheless, never pick any mushrooms you cannot fully identify!
Notes on edibility
Oysters are one of the safest mushrooms to eat and are sold on supermarkets. However, some people may be allergic to their spores. Additionally, they contain small amounts of arabitol, a sugar alcohol that may cause gastrointestinal upset in some people.
They are rather prone to maggots in the wild and therefore they don’t have a much extended shelf-life. It’s advisable to eat them as soon as possible, cleaning them first.
It is thought they help to reduce cholesterol levels, an effect linked to their content of beta-glucans.
Foraging in season
You can pick oyster mushrooms pretty much all year round in temperate climates, as they don’t react to seasonal changes but rather to weather changes; watch them in Winter after the first frost, Spring after the first hot days, Autumn after the first cold days and so on.
These mushrooms are saprotrophic, meaning they feed on decayed organic matter like logs and dying trees. Look for deciduous trees like beech and oak in open, leafy forests and parks, paying attention to trees fallen over or already struggling, mostly in shade. They tend to grow in abundance on large shelf-like clusters.
Oyster mushrooms grow incredibly quick and they will get tough or full of maggots as soon as they reach maturity. They are still good to eat though and I must say I enjoy big chunky stems as a diced meat substitute.
Oyster mushrooms can also be cultivated on straw, cardboard and even old cotton t-shirts. They were cultivated in Germany for first time as a subsistence measure during World War I. Today, it is grown commercially all over the world and domestic growing kits are sold on internet.
Storage and processing
Oyster mushrooms are usually a sanctuary to bugs and you will need to clean them as soon as you bring them home. Oysters are naturally moist and absorb like sponges, so use a minimum amount of water and press gently with a cloth to remove excess liquid.
Some people discard the stems because are tough, but I really enjoy them and always cut them off and set aside for a more meaty dish. Nevertheless, remove any remaining wood attached to the stem.
They can be preserved in several ways; you can store them in the freezer after briefly sautéing in butter, pickle them in vinegar or dry them, albeit losing some flavour and texture.
Culinary uses and recipes
Oyster mushrooms are delicate and have a mild sweet aniseed aroma. As a rule of thumb, the lighter the colour of the cap, the more subtle is the flavour, although wild varieties are more flavourful than the cultivated counterparts in general terms.
It’s a versatile mushroom that goes well in many dishes, but is commonly used in Oriental cookery and is the king of stir fries, because the cap is thin and cooks quickly. The flavour is enhanced with ingredients like garlic, prawns, cured hams or soya sauce (not all together please!)
They are widely used in Eastern European soups and stews and work really well in light cream sauces for meat. Just add them at the last stage of cooking after heated briefly in butter.
Thicker stems can be cut into large cubes and be dipped into crispy batter. I once used those thick stems to make an oyster filling for croquettes, with béchamel, parsley and garlic. They were divine!