Bolete mushrooms grow in the forests of Europe, Asia, and North America. They can be edible or poisonous. The edible ones, including the popular porcini mushrooms, are tasty and nutritious.
Here’s everything you need to know about bolete mushroom identification, nutrition, and health benefits.
What Is a Bolete Mushroom?
Bolete mushrooms grow in the wild. They have a unique, fleshy cap and a thick stem or stalk. Unlike typical mushrooms, the hymenium or underside of a bolete mushroom cap doesn’t have gills. Instead, it is a spongy surface with pores. These pores are connected to numerous tiny round tubes inside the cap. The inner walls of the tubes produce spores, which are released from the pores so that bolete mushrooms can multiply.
Bolete mushrooms belong to three genera or groups — Boletus, Leccinum, and Suillus. They include edible and poisonous mushrooms.
One of the most popular edible bolete mushrooms is Boletus edulis, also called porcini mushrooms, king bolete, or penny bun.
Unlike other mushrooms, bolete mushrooms don’t grow on composting material. They thrive near or under specific trees. They share nutrients with the roots, forming a symbiotic or mutually beneficial relationship with the tree. Leccinum species often grow near aspen, birch, and madrone trees. You can find Suillus species under Monterey pine trees native to central California. Boletus species like B. edulis grow in pine forests.
In the west, large numbers of bolete mushrooms appear under hardwood or conifer trees 10 days after the first heavy rains. In the east, they grow in summer and last for four to five weeks.
In Europe and Russia, fresh boletes like porcini are available in summer and autumn. Dried, canned, and pickled boletes are sold all year round.
How to Identify a Bolete Mushroom
Bolete mushroom identification is simple. They have a distinct appearance with a fleshy, spongy layer in the cap and pores on the underside. The stem can be easily separated from the cap. However, the exact species can be difficult to identify, which can be a problem because some boletes are poisonous or unpleasant to eat.
Here’s how you can identify edible boletes:
- Boletus. Edible Boletus species like B. edulis have a hamburger-bun-shaped, brown cap. They have a fat or bulbous stem with a network of white veins.
- Leccinum. Leccinum species are scaber-stalk or rough-stemmed mushrooms. The edible ones have white pores under a yellowish or reddish-colored cap. They have white pillar-like stalks with black scales.
- Suillus. Suillus species include mushrooms like slippery jacks. The edible species have narrow stems and slippery or sticky caps with grayish-white to yellow pores. Avoid consuming bolete mushrooms with red pores under the cap, as they can be poisonous.
What Is Bolete Mushroom Nutrition?
Bolete mushrooms are packed with nutrients. They are rich in dietary fiber and low in fat. For example, a 100-gram portion of fresh B. edulis or porcini mushroom contains:
- 81.8 calories
- 1.7 grams of fat
- 7.39 grams of protein
- 9.23 grams of carbohydrates
- 7.39 milligrams of iron
- 11.95 milligrams of calcium
It also contains vitamins B1, B2, B3, B5, B6, B9, C, and E as well as antioxidants like beta carotene, lycopene, and other flavonoids.
What Are Bolete Mushroom Health Benefits?
Bolete mushroom health benefits include:
Antioxidant effects. Bolete mushrooms have high levels of polyphenols or flavonoids like lycopene, beta carotene, and tocopherol or vitamin E. These antioxidant compounds help destroy harmful free radicals, which are reactive molecules that damage your cells and increase your risk of developing chronic illnesses. Antioxidants in bolete mushrooms help prevent free radical damage and protect your body from diseases.
Potential anticancer effects. Research shows that B. edulis extracts can reduce the growth of human breast cancer cells. The antioxidant effects of bolete mushrooms help protect cells from becoming cancerous and prevent cancer from growing.
Constipation prevention. Bolete mushrooms have high fiber content. Eating bolete mushrooms can help keep your gut healthy and prevent constipation.
Liver protection. With antioxidant properties, bolete mushrooms have anti-inflammatory properties that protect your liver against damage and disease. A study in mice with alcohol-induced liver damage shows that the mushroom B. cereus has liver-protecting effects. The antioxidants in the bolete mushroom protect liver cells from oxidative damage. The mushroom reduces the levels of inflammatory molecules and prevents inflammation in liver cells.
Antimicrobial activity. Bolete mushrooms have various bioactive compounds that show antibacterial and antiviral properties. Phenolic compounds like homogentisic acid, gallic acid, p-catechin, and others present in bolete mushrooms show antimicrobial effects. Bolete mushrooms can help prevent wound infection by drug-resistant bacteria.
Blood pressure control. The low sodium and high potassium content of bolete mushrooms are ideal for controlling blood pressure and preventing heart problems. Also, boletes are rich in fiber and antioxidants, which help prevent inflammation and keep your heart healthy.
How to Eat Boletes
Boletes are expensive and complicated to grow because they depend on specific trees for nutrients. They are collected from forests, so they can be rare to find and expensive to buy.
You can eat bolete mushrooms fresh, dried, or pickled. Here are some tips to eat bolete mushrooms:
- Always pick small and firm fresh boletes.
- Discard ones that are soft, wet, rotting, or filled with worms or insects.
- If you’re using an older bolete, remove the hard or fibrous stem, dark parts, slimy tops, and green or soggy pores — they can be challenging to cook and don’t taste good.
- If you’re using Boletus and Leccinum mushrooms, brush off their caps. For Suillus mushrooms, peel off the slimy parts of the cap.
- Boletes change quickly and must be preserved immediately. Slice them lengthwise and dry or freeze them. They’ll last for up to six months. Blanch boletes before freezing to extend their shelf life to a year.
How to Cook a Bolete Mushroom
Fresh bolete mushrooms have a delicious and earthy umami or savory flavor. The French way to cook them is to dry them partially in an oven and store them in the liquid they give out to preserve their flavor. Then, saute the mushrooms in olive oil or butter until they’re brown. You can serve them with meat or layer them over rice, risotto, pasta, or potatoes. You can also crumb-fry bolete mushrooms to enjoy their meaty texture and flavor. Some also eat them raw or pickled.
Dried boletes have a richer taste and a more powerful aroma than fresh ones. However, they don’t have the firm texture of fresh boletes. They are ideal for making soups and sauces. You can add them to enhance the flavors of salads, meat dishes, and other mushroom recipes. To cook dried boletes, soak them for 30 minutes. Once they’re rehydrated, saute them and cook them with the liquid they were kept in for more flavor.
What Are the Risks of Eating Bolete Mushrooms?
Some bolete mushrooms can be poisonous, such as those with red spores under the cap.
Bolete mushrooms collected from polluted or contaminated places may accumulate toxic heavy metals or radioactive chemicals like mercury, cadmium, cesium, or polonium. Bolete mushrooms store these metals in a non-toxic form. However, consuming large amounts of contaminated mushrooms can be dangerous.