Mushroom FAQs (Including "Are Mushrooms Good For You?")

I recently spent time with Eric Wallace, the owner of an urban mushroom farm in Columbia, South Carolina called Vital Fungi. There, he cultivates exotic varieties of mushrooms like Pink Oyster, Black Pearl King and Lion's Mane for local chefs and mushroom-lovers. 

Compared to other types of agriculture and farming, mushroom cultivation is a low-impact, low-resource form of food production. Eric believes in a regenerative approach to farming that encourages biodiversity and topsoil health, and in turn, produces healthy, nutrient-dense foods. His specialty mushrooms are a feast for the eyes, at once mysterious and beautiful.

Are Mushrooms Vegetables?

"Typically classed as vegetables, mushrooms are distinct substances called fungi and are more closely related to yeasts," advises Director of Nutrition Celine Beitchman. 

Of the thousands of varieties of mushrooms that exist, humans can only eat a portion of those that live above ground. (Only about 20 mushroom varieties are commercially cultivated.)

The table mushrooms we eat are a variety called Agaricus bisporus, and they include portobello, cremini and white button mushrooms. At certain times of the year, a yellow-hued variety called chanterelles can be found at farmers markets. They're harvested in the fall and early winter in the Northwest, and from early spring to late summer on the east coast.

Sourcing and Storing Mushrooms

When sourcing mushrooms at the grocery store or farmers market, look for quality mushrooms with firm, blemish-free exteriors. 

• A quality mushroom is whole with the stem attached and never slimy or fishy in smell. (I prefer picking my own versus buying pre-packaged and opt for whole over sliced.)
• Mushrooms should be dry, plump and springy.
• Fungi are active after harvesting and should be used shortly after purchase. 

Store your mushrooms between 38 and 42 degrees Fahrenheit with room to aerate. 

• Avoid plastic unless it is vented (like the clamshell containers for berries). This aeration allows for the gas exchange necessary to avoid sweating and spoilage. Completely sealed containers are hazardous and can create bacterial blooms that cause foodborne illness.
• Refrigeration slows down the mushroom metabolism, and they will last a week if loosely wrapped to prevent moisture or spoilage.
• Loose mushrooms should be stored in a reusable paper or Ziploc bag lined with a paper towel. You can leave the bag open.
• Dehydrate or dry mushrooms using a dehydrator or oven at 150 degrees Fahrenheit or less. Vacuum seal them in a bag for extended shelf-life.

Using Dried Mushrooms

When fresh mushrooms are not available, dried mushrooms are just as delicious and packed with flavor. I find dried mushrooms to be exceedingly versatile in dishes like risotto, soup and stir-fry. Many varieties like porcini and morels are easier to find dried than fresh, though they are pricey due to a short growing season. 

• Store dried mushrooms in an air-tight container in a cool, dry cabinet for up to a year.
• Dried mushrooms should be rinsed to removed sediment and rehydrated in warm water for 30 minutes to an hour.
• Strain the leftover water to use as a broth for soups and stews.

How to Clean Mushrooms

One of the most frequently asked questions about cleaning mushrooms is whether to wash them or not. 

• It is completely okay to wash whole common varieties of mushrooms like cremini, portabello, chanterelles or baby bellas right before cooking — but they'll absorb water like a sponge.
• Chefs gently clean mushrooms with a pastry brush to remove debris.

Are Mushrooms Good for You?

Mushrooms are a low-calorie food packed with vitamins, minerals and antioxidants, notably more protein and vitamin B12 than most fresh produce. Shiitakes are loaded with health benefits, including a unique compound called AHCC that stimulates the production and activity of natural killer cells and T cells, the immune system's first line of defense against viral infections and cancers.

"While mostly carbohydrate, unlike other 'plants,' a mushroom’s cell walls are made of chitin, a type of fiber so tough that humans can barely digest it," explains Chef Celine. "This cellular membrane is distinctly different from softer cellulose (e.g. insoluble fiber or roughage) that surrounds other edible plants which, in most cases, can be digested raw. Chitin is the main reason mushrooms are best served cooked — [this allows us to] access all of the nutrients inside the cell. It’s why a plate of mushroom ceviche may give you a bellyache as it makes its way through your GI tract intact."

"One amazing feature of all mushrooms is their ability to convert sunlight into D2 — an inactive form of vitamin D — which humans can digest and benefit from," adds Chef Celine. 

"This is especially useful for individuals who avoid animal foods or who may avoid getting adequate sunlight and need to meet vitamin D requirements nonetheless. In addition to nutrients typically found in produce, mushrooms are also good sources of nutrients typically found in meats and grains — niacin, pantothenic acid, selenium, riboflavin and copper."

Both wild foraged and cultivated mushrooms can be dried in the sunlight to boost their vitamin D content, and with eight essential amino acids, they are just one shy of being a non-animal complete protein source.

"Beyond macronutrients and essential micronutrients, mushrooms also contain bioactive compounds that may improve human health," Chef Celine says. 

"These include polysaccharide beta-glucans that research suggests play a role in insulin sensitivity and sugar-handling, support immune function, and may be cancer-preventative. And, mushroom polyphenols — that give distinct flavors and textures to each species — may play a role in reducing oxidative stress and thereby protect against degenerative brain disease."

Cooking Mushrooms

"When cooked, mushrooms are delicious sources of carbohydrates and glutamic acids that, when roasted or sautéed at high temperatures, yield savory, umami flavors that can mimic smoked meats," Chef Celine says. The taste can be earthy, buttery, savory and woodsy. Cooking releases all of the nutrients, aromas, and deep, earthy flavors and are essential for getting the most nutritional value.

See a student recipe with five types of mushrooms.

The best and simplest way to cook mushrooms is a simple simmer with ¼ cup water to a pound of mushrooms, then add oil and garlic, and finish with herbs, lemon or sherry vinegar. Pasta, stews and risottos are instantly elevated by adding mushrooms. Golden chanterelles are best when sautéed in fat with a pinch of sea salt, minced garlic, and deglazed with sherry vinegar or cream.