The Complete Guide to Portobello Mushrooms

Portobello mushrooms are some of the most famous fungi in the world. Their strong umami flavor and large size make them a fantastic meat replacement and a great side dish to any meal.

Recent research shows that these fungi aren’t only great in the kitchen. Some studies point out that they have several therapeutic properties, which could make them helpful in developing new medications. Here’s what you need to know.

What are portobello mushrooms?

Portobello mushrooms, also known as portabella or portabello, are the largest and most mature variety of the famous Agaricus bisporus. Portobellos are also sometimes referred to as baby bella mushrooms when they are younger specimens. Yet, there’s some disagreement on this whole matter—we’ll expand on this later.

Known for their large size and chewy, meaty texture, portobello fungi (along with the other A. bisporus varieties) are the most common mushrooms used in kitchens all over the world.

Experts estimate that all the A. bisporus varieties together generate billions of dollars in revenue each year. In fact, they’re so widespread that people have nicknamed portobellos and button mushrooms “common mushrooms.” 

Agaricus bisporus tends to grow in the northern hemisphere, with a slight preference for tropical climates. However, the species is so distributed that there have also been reports of it in the southern hemisphere. Its fruiting bodies usually appear from late spring to early autumn (1) (2).

Unlike button mushrooms (the smallest A. bisporus variety), portobellos have a strong and savory umami taste slightly resembling smoked meat. Their odor is somewhat earthy, and their texture is dense, chewy, and thick. This makes them the perfect replacement for meat—either as an ingredient for more complex recipes or as a main dish on their own.

How do portobello and baby bella mushrooms look?

Agaricus bisporus is a versatile mushroom, changing quite a lot depending on the fruiting body’s maturity stage. The mushroom cap measures 2.5–14 cm (1–5.5 in), and its stem is 2–7 cm (0.7–2.7 in) long. The color ranges from white to brown, and the stem will show red or dark spots when bruised (1) (2).

Portobellos fall on the bigger side of these measurements, with mushroom caps usually at least 10 cm (3.9 in). On the other hand, baby bellas are smaller but retain the distinctive brown color and meaty texture.

That said, there aren’t any strict guidelines separating portabella mushrooms and baby bella mushrooms from other varieties. Instead, mushroom cultivators and harvesters label them according to size and color.

What are the varieties of portobello mushrooms?

There aren’t any varieties of portobello mushrooms as they can be considered a variety themselves. The scientific community has identified six Agaricus varieties—however, it isn’t clear if portobellos refer to a specific one (3):

• Agaricus bisporus var. albideus
• Agaricus bisporus var. avellaneous
• Agaricus bisporus var. bisporus
• Agaricus bisporus var. burnettii
• Agaricus bisporus var. eurotetrasporus
• Agaricus bisporus var. pettubescens

While we know that, for example, the albideus variation refers to white button mushrooms and avellaneous to creminis, it’s hard to determine which one corresponds to portobellos. Also, not everyone agrees that these varieties or strains actually exist.

You’ll find many mycologists online claiming that Agaricus bisporus has no varieties. Instead, they claim that portobellos, white mushrooms, and all other strains are the same A. bisporus variety harvested at different stages of maturity.

This can be confusing, we know.

It’ll be easier for most people to consider two varieties instead. The first one is what’s traditionally known as champignons or button mushrooms. These fungi are small, white in color, and usually cheaper than other types of mushrooms. You can use them as toppings for pizzas and salads or as ingredients in soups and stews.

The other one is portobellos, which are not only larger but also brown in color. They’re also more expensive and will usually have a stronger savory flavor. These are perfect for serving alone or replacing meat in most recipes.

Naturally, you’ll find many Agaricus bisporus fungi that don’t fit these categories exactly. Cremini mushrooms (also called baby bellas), for example, are small to intermediate mushrooms that are brown instead of white. But don’t worry—these variations will have almost the same taste and nutritional values as champignons and portobellos.

History of portobello mushrooms

Portobellos have been around for a very, very long time. This species probably has grown in the wild since prehistoric times, so it’s not crazy to think that our oldest ancestors ate them.

It’s also possible that ancient civilizations such as Ancient Egyptians, Romans, and Greeks were able to enjoy these delicious fungi. Experts point out that these civilizations held fungi in the highest regard, claiming they were the gods’ gifts to nobility (4) (5).

However, the first known mention of Agaricus bisporus dates back to the 1600s, when European farmers started noticing these fungi growing underground. They observed that they usually grew in dark, humid areas such as cellars and catacombs. Later, they began cultivating them after theorizing that mycelium could act as “seeds” for these fungi (5).

It wasn’t until the 1890s that the first scientific mention of A. bisporus appears. At the time, a group of mycologists became fascinated by these fungi growing in North America. Charles Horton Peck, a renowned mycologist at the time, named and described it as Agaricus brunnescens. This name is now considered to be a synonym of A. bisporus (6).

In 1926, American mycologist Louis Ferdinand Lambert isolated the genes for white mushrooms. This made portobellos and creminis disappear from markets as white specimens were considered to be more desirable at the time.

However, in the 1980s, marketing professionals rebranded portobellos as the more flavorful variety of A. bisporus. The campaign had a lot of success and led to portobellos being the popular fungi they are today (7).

Health benefits of portobello mushrooms

Agaricus bisporus has historically been largely overlooked regarding its potential health benefits. However, recent research shows that this species not only has several therapeutic properties, but also significant nutritional values.

A 100-gram serving of portobello mushrooms is composed of 90% water. Yet, it also contains 3 grams of protein, 4.5 of carbohydrates, and only 0.5 of fat. The serving only amounts to an astounding 29 calories. It also has several micronutrients, including (8):

• Vitamin A
• Vitamin C
• Vitamin D
• B vitamins
• Potassium
• Calcium
• Magnesium
• Selenium

As for health benefits, it shares the same properties as white button mushrooms. For example, portobellos contain two proteins (ABL and Abmb) that may stimulate the immune system. Researchers theorize that this could slow down cancer growth (9).

These fungi also contain a polysaccharide known as “fucogalactan,” which has anti-sepsis, antinociceptive, and anti-inflammatory properties. This compound could, in turn, help manage and treat tissue damage (10).

More experimental research on mice and rats also shows that portobellos could reduce blood cholesterol and glucose levels. The same article also states these mushrooms could help reduce age-related brain function decline (11) (12).

Still, none of these benefits are fully confirmed. As such, check with your doctor before using portobellos for medicinal purposes.

Where do portobello mushrooms grow?

Agaricus bisporus grows all over the world—its lax growth conditions and popularity have led to it being one of the most widespread fungi we know. Still, surprisingly, there’s very little information about where it actually grows in nature.

Portobellos are usually found in what’s known as “enriched spawns,” including compost piles and manured soil. As such, spotting them in horse stables or grasslands where cattle feed and pasture is common.

The fruiting bodies appear from late spring to early autumn. They seem to prefer growing in tropical areas in the northern hemisphere—although there have been reports of them growing in southern countries as well (1) (2).

Agaricus bisporus is considered a relatively easy mushroom to grow, making portobellos the perfect starting point if you want to start growing your own mushrooms.

What is ethical wildcrafting?

Ethical wildcrafting refers to a set of guidelines that aims to help you reduce environmental damage when harvesting mushrooms from the wild. If you don’t know what wildcrafting is, it’s similar to foraging—but with the vital difference that the former refers to harvesting for medicinal purposes and the latter for eating.

Going wildcrafting without considering these ethical guidelines can lead to considerable damage to your local fungi populations. But don’t worry—keeping the environment healthy is as easy as:

• Conducting some research before heading out and taking note of endangered (or poisonous) species
• Not disclosing patch locations to other people
• Avoiding harvesting lookalikes instead of your desired mushrooms
• Picking the fruiting bodies gently to avoid damaging the mycelium
• Asking for permission from the landowner (if harvesting on private land)
• Checking local harvesting laws (if harvesting on public land)

Following these rules of thumb not only help keep fungi healthy but also the animals and insects that benefit from local mushrooms. If you’re new to harvesting, we recommend looking for harvesting groups in your area to teach you the basics of ethical wildcrafting.

Is it safe to wildcraft for portobello mushrooms?

Unfortunately, it’s never 100% safe to eat wild-picked mushrooms. Portobellos, like all other A. bisporus varieties, have several toxic lookalikes. The most famous ones are the darker varieties of the yellow stainer (Agaricus xanthodermus), which can cause food poisoning.

Even if you’re entirely positive that you’ve picked the right species, wild mushrooms can contain environmental pathogens. In turn, this could lead to indigestion and other gastric problems. As such, make sure to only eat wild fungi with the approval of a professional.

How do you take portobello mushrooms?

Portobellos (and Agaricus bisporus in general) are considered some of the most versatile mushrooms in the market. They can be served on their own, as a side dish, and cooked however you like. Plus, they can be the perfect meat substitute for vegetarian home cooks.

For example, portobello mushroom burgers are a top pick among those who want to reduce their meat consumption. Similarly, stuffed portobello mushrooms and mushroom soups are easy recipes that can be prepared in minutes.

If you don’t have large portobellos, some recipes can also be done with smaller specimens. Imagine some Italian pasta topped with olive oil, fresh thyme (or other fresh herbs), black pepper, parmesan cheese and sliced mushrooms. Sounds good, right?

An even simpler option is to add portobellos to sauteed veggies in canola oil. Then, place the mixture in a tortilla (with a dollop of guacamole, of course!) to make delicious, vegan-friendly tacos.

But they don’t have to be part of your main meal—baked portobellos can also be a great appetizer. Consider these recipes for portabella appetizers and serve them at your next get-together.

Don’t be afraid to experiment. Portobellos are simple ingredients that can be added to almost any dish if you’re creative enough. Even if you don’t feel confident in your cooking skills, the internet is filled with thousands of portobello mushroom recipes.

Portobello mushrooms: The giants of fungi

Portobellos are the biggest variation of the famous Agaricus bisporus. Known for their distinctive brown color and savory flavor, these fungi are the perfect meat substitute for any amateur cook. Plus, they’re among the most common mushrooms in the world, so you can find them at almost any grocery store.

If you want to find out about other types of mushrooms, keep up on shroomer. Here, you’ll get all the details you need about psychedelic and functional fungi from around the world, along with the latest news on medicinal research on edible mushrooms.

References

1. Kuo, M. “Agaricus Bisporus.” (2018). https://www.mushroomexpert.com/agaricus_bisporus.html
2. Paul Stamets, J.S. Chilton. “Agaricus brunnescens Peck.” in The Mushroom Cultivator (1983), 164–167.
3. MycoBank. “Agaricus bisporus.” No date. https://www.mycobank.org/page/Name%20details%20page/708
4. Adel F. Ahmed, Ghada Abd-Elmonsef Mahmoud, Mohamed Hefzy, Zhenhua Liu, and Changyang Ma. “Overview on the edible mushrooms in Egypt.” Journal of Future Foods 3 (2023): 8–15. https://doi.org/10.1016/j.jfutfo.2022.09.002
5. Zeina El-Sebaaly, May Hammoud, Youssef Najib Sassine. “History, health benefits, market, and production status of button mushroom.” Crop Production Science in Horticulture (2021). https://www.cabidigitallibrary.org/doi/abs/10.1079/9781800620414.0001
6. David Malloch. “Agaricus brunnescens: The Cultivated Mushroom.” Mycologia, 68(4) (1976): 910–919. http://www.jstor.org/stable/3758807
7. Specialty Produce. “Portobello Mushrooms.” No date. https://specialtyproduce.com/produce/Portobello_Mushrooms_702.php
8. FoodData Central. “Mushrooms, portabella, grilled.” April 2019. https://fdc.nal.usda.gov/fdc-app.html#/food-details/169243/nutrients
9. Wangsa Tirta Ismaya, Raymond Rubianto Tjandrawinata, and Heni Rachmawati. “Lectins from the Edible Mushroom Agaricus bisporus and Their Therapeutic Potentials.” Molecules, 25(10): 2368. https://doi.org/10.3390%2Fmolecules25102368
10. Andrea C. Ruthes, Yanna D. Rattmann, Simone M. Malquevicz-Paiva, Elaine R. Carbonero, Marina M. Córdova, Cristiane H. Baggio, Adair R.S. Santos, Philip A.J. Gorin, Marcello Iacomini. “Agaricus bisporus fucogalactan: Structural characterization and pharmacological approaches.” Carbohydrate Polymers, 92(1) (2013): 184–191. https://doi.org/10.1016/j.carbpol.2012.08.071
11. Sang Chul Jeong, Yong Tae Jeong, Byung Keun Yang, Rezuanul Islam, Sundar Rao Koyyalamudi, Gerald Pang, Kai Yip Cho, Chi Hyun Song. “White button mushroom (Agaricus bisporus) lowers blood glucose and cholesterol levels in diabetic and hypercholesterolemic rats.” Nutrition Research, 30(1) (2010): 49–56. https://doi.org/10.1016/j.nutres.2009.12.003
12. Nopporn Thangthaeng, Marshall G Miller, Stacey M Gomes, Barbara Shukitt-Hale. “Daily supplementation with mushroom (Agaricus bisporus) improves balance and working memory in aged rats.” Nutrition Research, 35(12) (2015): 1079–1084. https://doi.org/10.1016/j.nutres.2015.09.012