King Oyster Mushroom Cooking

Candidates For Cultivation: The King Oyster Mushroom

Oyster Mushrooms come in a dizzying variety of colors, shapes and sizes. One true standout is the king oyster mushrooms. Unique in many of its characteristics, the King Oyster has a stately appearance and culinary flexibility making it well deserved of its name.

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Scientific Name: Pleurotus Eryngii

General Description

Unlike other oyster varieties, the King Oyster doesn’t usually produce a shelf like formation, but instead produces a mushroom with a round cap and a defined stem. The cap usually unrolls with age, becoming flat and eventually uncurled. If grown indoors with minimal fresh air and low light levels, the mushroom will grow a fat tall stem and a tiny cap, while lots of fresh air and light will produce a mushroom with a small stem and large dark cap. King Oysters can be quite large, sometimes producing single fruits weighing well over one pound.

king oyster mushrooms growing indoors

King oysters growing indoors.

Genetically identical, growing outdoors.

Natural Habitat: Found growing from the roots of hardwood trees, emerging from underneath the soil. Can be found in Southern Europe, North Africa, Central Asia and Russia.

Difficulty: Medium.

Agar: King Oyster mycelium grows vigorously on Malt Yeast Agar. Growth is somewhat slower than other Oyster species. Mycelium appears thick and fluffy. Sometimes rhizomorphic.

Spawn Types: Grains, especially Rye. Can also use millet, or wild bird seed. Hardwood sawdust is also an effective spawn medium.

king oyster on agar

King Oyster growing out on Agar.

king oyster on rye

A liquid Culture of King Oyster growing through sawdust.

Substrate Types: King oyster grows best on supplemented hardwood sawdust in autoclavable grow bags. Supplement with wheat bran at 10-15%. King Oysters will also grow well on straw, however, unlike other Oyster species, the yield will be reduced. Cultivators also report that the King Oyster will have a longer shelf life and a better texture if grown on hardwood sawdust rather than straw.

Fruiting Containers: Large gusseted autoclavable grow bags with a filter patch will produce the best results. For straw logs use poly tubing. Can also be grown with success outdoors in garden beds.

Casing Layer: Unlike other Oyster mushrooms, the King Oyster will benefit from a casing layer. Use 50/50 peat moss and vermiculite with 1% hydrated lime to prevent casing contamination.

Yield: Typically, 1 lb can be grown from a 5 lb supplemented sawdust block on the first flush. Multiple flushes can be achieved. Some cultivators get 2 lbs from a block on a single flush.

baby king oyster mushroom

Baby King Oyster Emerging from a casing layer.

king oyster mushrooms

Indoor grown King Oysters at different stages of development

Harvest: When to harvest the King Oyster depends on cultivators preference. Smaller younger mushrooms will generally have a better texture and flavor, but less yield will be achieved. King Oysters are unique among oysters in that the stem is highly desired for culinary uses, so allowing the stem to grow large may be desired. Harvest by removing the mushrooms at the base of the stem, being careful not to damage the top of the block if subsequent flushes are desired.

harvested king oysters

Freshly harvested King Oyster Mushrooms. Grown indoors. Yum.

Weakness: King Oysters are generally resilient against contamination but can be susceptible to blotch. Blotch is a bacterial infection generally caused by excessive humidity. It is shown by dark spots on the mushroom fruitbody. Remedy by reducing the humidity and ensuring water droplets do not remain on fruitbody for too long. Increase air exchanges.

Cooking: King Oyster mushrooms have a thick meaty texture and a bold unique taste. They are quite versatile and highly desired as a culinary treat. The thick texture will even stand up to grilling on a BBQ!

The Specifics

Spawn Run:
Incubate the grain spawn at room temperature (20-22 deg C) until full colonization. Should take 10-14 days for full colonization.

Initiate Pinning:
Expose fruiting container to lower temperatures (15 deg) and high humidity (95-100% RH). Increase fresh air.

Fruit Development:
Temperatures between 15-18 deg C. Lower humidity slightly but maintain above 80%. Fruits develop in 4-8 days.

You will not be disappointed choosing to grow King Oyster! The ones you grow at home will generally be much more delicious than the imported ones you can buy from the grocery store. They are fun to watch grow, as they grow large and relatively fast. They store for much longer in the fridge than typical oyster mushrooms, sometimes lasting for longer than 2 weeks. You can have fun altering the growing conditions to produce vastly different looking mushrooms. Overall, the King Oyster mushroom is a perfect candidate for cultivation.

Thanks for reading! Post comments, or pictures of your own King Oyster grows below!

-spread the spores-


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Comments 18

    1. Post

      Hi Kerem!

      Yup, it’s a good idea to pasteurize the casing layer. I also like to add a little bit of hydrated lime. These two things together will go a long way towards keeping your casing layer to get contaminated.

      Once your casing layer is mixed and water is added to “field capacity”, pasteurize around 75 deg C for an hour. The easiest way to do this is to place your casing inside a filter patch grow bag and pasteurize on the stove. You will need to place a weight on top on order to hold the bag mostly under the water, but try to keep the filter aboove the water line.

      Hope that helps!

  1. Hello, how long should it generally be to the initiate Pinning stage, after you have spawned to the substrate??

    1. Post

      It depends on a number of factors, but generally anywhere from 10-14 days. If you have a high spawn rate, and good mixing, it will be closer to ten. Sometimes you can leave it in the bag for a number of weeks before you fruit them, but kings will readily form pins on the top of the block under the bag.

    1. Post

      Hey Sue! Right before I put them into the fruiting chamber- so pretty much as soon as they are ready to fruit and the top of the bag is cut off. I add about 1 inch deep peat moss pasteurized and treated with lime.

      1. Thanks so much for “both” your answers Tony! Since my spawned kings are looking fully colonized and are 16 days old, I’m going to go put them in my outdoor fruiting chamber, I’m so excited!!! I just started this hobby a couple months ago, bought a King culture syringe, started it on agar, then to rye grain jars and then to substrate of sawdust with BBQ alder chips, wheat bran, a little millet, coffee grounds, gypsom and cardboard, lol, I hope that wasn’t too many ingredients, but the bags look good! Thank you again for your quick reply!

        1. Post

          Awesome! I wish you mush success- sounds like you are well on your way to growing some Kings! Outdoor kings are the absolute best. Let me know how it turns out!

          1. I have Pins!! A few have brown heads, others are gray.. does that mean one of those colors are aborting? 2 more bags went into the greenhouse today too! I have never eaten (or even seen) a King Oyster so I can not wait to try them!

          2. Post

            Exccellent! Good job! The pins can vary in color, so I wouldn’t worry about it too much. Sometimes they will abort if it is too dry, other times they will just abort to let the bigger ones grow. Good luck!

          3. They started to flatten out and I picked them (just the bigger flattened ones) and ate them! They ARE delicious! I had a very nice helping of them, sauteed with a tiny bit of spices and garlic. I’m so glad my first bag was a success, thank you for you help! My Shiitake are starting to fruit too!

          4. Post

            Way to go sue! It’s always satisfying to pick your own home grown mushrooms! Good luck with the Shiitake-

    1. Post

      Hey Dave! No, I don’t scratch the top. I have tried it in the past, but it doesn’t seem to make a difference for me. I know some people do though, and get improved pin sets on the block, so your miles may vary.

    1. Post

      Hey There!

      I like to use bags because it is easier to sterilize and compartmentalize. If you just do one large bed, it would be difficult to sterilize all the substrate and keep it sterile while it is colonizing. Also, if you do get contamination, its much better to get it in just one bag that you can toss rather than a whole bed.

    1. Post

      Hey Victor!

      I would be hesitant to grow on straight coffee grounds. You might instead try to add coffee grounds to another sitable substrate as a supplement. I know people have had success growing regular oysters on coffee (Pleurotus ostreatus) but not sure about eryngii. Coffee is prone to contamination.

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