King oyster

What it is

King oyster (Pleurotus eryngii), also sold as king trumpet, royal trumpet or eryngii, is the largest common oyster mushroom and the least oyster-like. It grows as a thick, solid white stem with a small tan cap on top. Most of what you eat is stem.

It's native to the Mediterranean, Middle East and parts of Asia, and it's grown commercially on a large scale in the US. Several of the small farms in our directory grow it too.

Taste and cooking

The stem is dense and mild, and it browns beautifully. Cooks use it where they want a meaty bite.

• Coins: Slice the stem crosswise about 2 cm thick, score a crosshatch on both faces, and sear in a hot pan with oil until deep golden. They look and chew a bit like scallops. Finish with butter, garlic and soy sauce.
• Planks: Cut lengthwise into thick slabs and grill or griddle them.
• Shreds: Pull the stem apart with a fork into strands and crisp them for tacos or sandwiches.

Because the stem holds less water than other oysters, king oysters keep their shape and don't shrink as much. Cook them through.

How it's grown

King oysters grow indoors on supplemented hardwood sawdust, often in bottles or bags. Unlike most oysters, which want lots of fresh air, growers raise king oysters under conditions that push the stem to grow long and thick before the cap opens. Because it's a controlled indoor crop, it's available all year.

Storing it

King oysters keep better than any other oyster mushroom. Store them in the refrigerator in a paper bag or their original container, as Penn State Extension recommends for fresh mushrooms. Check them before cooking: a fresh stem is firm and bright white. Yellow patches, a spongy feel, wet spots or a sour smell mean they're past their best.

Where to buy king oyster

11 growers in our directory list king oyster by name@if ($ohio->isNotEmpty()), 6 of them in Ohio. Availability changes with the season and the harvest, so check with the farm before you go.

See all 11 growers in the directory, or start with Ohio.

Does the science say…?

There isn't much human research on king oyster specifically. It's a nutritious food, and it belongs to the same genus as the oyster mushrooms covered in a 2020 review of clinical trials on blood sugar and cholesterol (see our oyster guide), but those trials tested Pleurotus ostreatus, not king oyster.

Penn State researchers who measured the antioxidants ergothioneine and glutathione across mushroom species found wide differences from one species to the next (Kalaras et al., 2017). That's a measurement of what's in the food. It isn't evidence of a health effect, and we don't know of any human trial showing one for king oyster.