Button Mushrooms
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Button Mushrooms (also known as Common Mushrooms, White Button Mushrooms, White Mushrooms, Table Mushrooms, Cultivated Mushrooms, Agaric Cultivé, Champignon Mushrooms and Champignon de Paris) is the most common mushroom consumed in the United States. The average American eats around 2.2 pounds (1 kg) of Button Mushrooms, each year.

Button Mushrooms are native to grasslands in Europe and North America, where they originally had a pale grey-brown color with broad flat scales. Their flesh is firm and white although it turns a pale pinkish-red with bruising.Button Mushrooms fit the model, of the typical Mushroom (sporophore) and consist of a Cap (Pileus) and a Stem or Stalk (Stipe).

Scientifically, Button Mushrooms are the most immature form of the edible species Agaricus Bisporus. “Agaricus,” refers to “gilled mushrooms” and "bisporus" refers to the fact that White Button Mushrooms have a two-spored basidia lining their gills. If you ever see the scientific term Agaricus brunnescens that is a former name for Button Mushrooms which refers to how Button Mushrooms oxidate and turn brown when exposed to air or bruised. They also turn brown as they age.

Savvy marketers have used this change in coloring to their advantage and today Agaricus, surprisingly, shows up in grocery stores in three forms. Obviously, they are sold as Button Mushrooms, but they are also marketed as cremini mushrooms in their juvenile form and as portobello mushrooms in their mature form. The only difference between the three is age / growth. You have to give the farmers marketing credit for knowing that consumers would pay more for a cremini or portobello, than for a larger Button Mushroom.

The earliest attempts to commercialize Button Mushrooms date back to France in 1707 when French botanist Joseph Pitton de Tournefort transplanted brown Button Mushroom mycelia to beds of composted manure. His efforts were sporadically successful but were subject to Pathogens and failure to thrive. In 1893, the Pasteur Institute was more successful with sterilized growing conditions.

Modern cultivated White Button Mushrooms are a relatively new discovery and almost all are sourced from a single aberrant white strain discovered in Pennsylvania in 1926. At the time, the white color was perceived as more attractive and that same mutant strain has been grown ever since. White Button Mushrooms are small, stark white mushrooms with smooth rounded caps and short truncated stems.

Season

Button Mushrooms are grown commercially all year. Because they are harvested daily, grocery shoppers don’t have to worry about any “seasonality.”

If you had to search for a season for wild Button Mushrooms, it would be late spring through early fall but Button Mushrooms don’t really use seasonal light to time their reproduction anyway. Instead, they rely on moisture and temperature to denote an auspicious time to sprout Mushrooms which would release spores. This is why you may see them sprouting off of the forest floor after a good, cool rain. Commercial growers use similar moisture and temperature cues in a controlled environment to trick Button Mushrooms into sprouting on an established schedule.

Availability

With Button Mushrooms grown in natural and controlled environments throughout the world today, fresh Button Mushrooms can generally be found in American grocery stores year around.

Dried Button Mushrooms, Canned Button Mushrooms, Frozen Button Mushrooms and Mushroom Powders are also year round options.

Cultivation

Button Mushrooms are a fungus and not technically plants. As a distinct organism, with unique characteristics, they require different growing conditions than a run-of-the-mill garden Vegetable we are used to growing.

First of all, Button Mushrooms don’t create their own food from soil and sunlight through photosynthesis like plants. Instead they feed off of decaying matter which makes them “heterotrophs.” In the case of Button Mushrooms there is a wrinkle because they can only absorb nutrients that have already been broken down by bacteria and other fungi. This makes Button Mushrooms secondary decomposers and the bacteria and other fungi the primary decomposers. The practical effect is that Agaricus grows best on composted material.

Though we desire the Mushroom Caps and Mushroom Stems, the bulk of the Agaricus Mushroom fungus organism, the mycelium, tends to grow underground, or at least out of sight. It is there even when we don’t see any Mushrooms sprouting from the earth.

The part that most of us consider a Mushroom is actually only the fleshy fruit of the organism. Basically, when it feels that the time is right to reproduce, the organism sends out spore producers (mushrooms) to fire reproductive spores into the environment. Because of their reproductive role, Scientists call the sprouting, spore-firing, Mushroom a “Sporophore,” which translates from the Greek as a “Spore Producer.”

With the scientific terms it may be a bit confusing. Put more simply the edible Mushrooms that we fancy are analogous to the apples of an apple tree. They are the fruit of the larger fungus. Instead of seeds, Mushrooms have spores.

Mushrooms tend to prefer moist environments (95-100% humidity) and can grow quickly on apparently open ground, especially after heavy rains. With the right conditions, "a mushroom doubles in size every 24 hours” according to Jim Angelucci  General Manager of Phillips Gourmet Mushrooms, one of the iconic Pennsylvania growers. In fact, because of their growth rate, Jim stresses that “It’s imperative that mushrooms be harvested at the proper time."

Button Mushrooms come from two primary sources: indoor trays, and wild harvesting / foraging.  Larger commercial farmers use indoor trays stacked like bunk beds in mushroom sheds. They grow their mushrooms on various composted substrates (wood chips, sawdust, mulched straw, horse manure, corncobs, nut shells, etc.) preferred by the Button Mushrooms. Generally, the ideal substrate has moisture levels of about 50%-75% and contains enough nitrogen and carbohydrates to promote rapid growth.

Insects, bacteria and other fungi can constitute a parasitic risk to growing Mushrooms so cultivators control their growing environment to eliminate such risks. Cultivated Mushrooms are raised in a fairly sterile environment. You will probably want to protect your Button Mushrooms if you choose to grow your own.

Though we discourage it, Button Mushrooms may be foraged as well. There are plenty of guides to help people determine which wild fungi are edible Button Mushrooms. If you decide to take this dangerous route, make sure to have an experienced person guide you. Double-check what you’ve picked before eating it.  For us, good grocery stores with interesting, revolving selections are the perfect foraging grounds, without any of outside time and none of the risks.

Many vendors sell Button Mushroom Growing Kits for home users aiming to experiment. There is also a good book by Paul Stamet called “The Mushroom Cultivator: A Practical Guide to Growing Mushrooms at Home.” If you want to grow Mushrooms in a larger way, Paul Stamet’s other major work: “Growing Gourmet and Medicinal Mushrooms“ is very helpful.

Production

Production of Button Mushrooms is a major part of fungiculture. Button Mushrooms are grown in more than 70 countries and Button Mushroom production accounts for about 40% of total worldwide volume of Mushrooms or about 1.5 million tons.

In the U.S. Button Mushrooms are even more dominant and make up about 90% of our domestic Mushroom business. More than 793 million pounds of Agaricus (Button Mushrooms and Cremini Mushrooms) are grown in the United States each year. Forty three percent of these domestic Button Mushrooms are grown in Chester County, Pennsylvania, in the southeast corner of the state, whose 60 odd Mushroom farmers produce more than 340 million pounds of Button Mushrooms a year worth about $400 million.

There is no special soils geology or topography at work in south eastern Pennsylvania, just synergy and generations of industrious Americans. Sometime around 1885, some local, Quaker carnation growers sought to maximize the dark wasted space beneath their flower beds in their greenhouses. Button Mushrooms which grow well in the dark came to mind. They imported European techniques and spores and started growing Button Mushrooms.

Italian stone workers, laid-off from nearby quarries, were hired to perform the physical labor. The Italians started their own farms. So did their kids and relations. By the ‘50s, Italian mushroom farmers were plentiful around Kennet Square, PA and Chester County was on its way to becoming today’s Mushroom Capital.

The methods for growing Agaricus are vastly different from growing most other sorts of mushrooms. First of all, Button Mushrooms are secondary decomposers, which means that they need compost for sustenance and that cultivating them involves a lot of composting.

The aim of commercial mushroom composting is to provide an optimal growing environment for Button Mushrooms without encouraging other competitive fungi. Some of the bigger farms can have more than 20 acres of steaming, reeking mounds of cocoa shells (from the Hershey chocolate factory), corn cobs, chicken manure, hay, horse manure, etc.

In nature, Mushrooms are typically in a vegetative state. They only go into a reproductive state, sending up Mushrooms (also called fruiting bodies) to spread spores, when they are triggered to do so by cues in their environment such as cold or precipitation. This is why we see so many Mushrooms sprout up after a rain.

Many common Fungi use seasonal light as their signal to form fruiting bodies. Button Mushrooms don’t. They take their reproductive timing cues from the humidity, the barometric pressure and temperature of the casing layer and the substrate upon which they are growing.  Mushroom cultivators take advantage of the Mushrooms’ cycle and manipulate the temperature, the CO2, and the humidity in the environment to artificially scare them into thinking it is time to reproduce.

Consequently, most Button Mushrooms are grown in cool dark places 59 to 64˚ F (15 to 18˚ C) with high relative humidity. Some Agaricus farms are based in underground caves, but more commonly "mushroom houses" are built. They are like small barns, with relatively small rooms (to more easily control humidity and temperature) crammed with “bunk beds” holding trays of growing mushrooms.

Mushrooms grow in repeating 3- to 5-day cycles called "flushes" or "breaks." In commercial production, three to five flushes are picked before the crop is pulled to start over with a fresh crop. During cropping, the casing layer is watered 2 to 3 times per week. A production cycle can take up to 15 weeks from first composting to final harvest. Young Button Mushrooms are picked before the veil breaks and the stem elongates.

Because they are cultivated in a fairly sterile environment to avoid contaminating the substrate with competitive fungi and pesky pathogens, Mushrooms, which are picked by hand, emerge from the ground remarkably clean. Mushroom harvesters grab a handful, pull and twist gently to release the Mushroom. They trim the stumps with a knife and grade them according to size and quality. A good harvester can pick up to 100 pounds (45 kg) an hour.

Varieties

Cultivated Button Mushrooms (Agaricus bisporus) are the most commonly found members of the Agaricus family but there are some other wild relatives, which may end up in a forager’s pack or a farmer’s harvest and eventually on your grocer’s shelf in lieu of actual Agaricus Bisporus. Some of the “cousins” have better flavor but can be hard to identify.  Some of these “cousins” include:

Agaricus Arvensis, nicknamed “The Horse Mushroom,” because it is commonly found near stables, has a licorice odor and is claimed by some to be among the most delicious of Mushrooms. Be careful though it is often confused with the deadly Amanita genus.

Agaricus Augustus, called “The Prince Mushroom,” is larger than the A. bisporus and found more commonly in the western U.S. The Prince has a flavor that reminds one of almonds.

Agaricus Bitorquis, also known as the “double ring” agaricus. The Double Ring is abundant and has a stronger flavor than Agaricus Bisporus. It is also more robust and able to hold up in the distribution system. At times mushroom growers cultivate A. bitorquis instead of A. bisporus.

Agaricus Campestris, labeled the “Meadow Mushroom” or “Field Mushroom” is the closest wild cousin to cultivated Button Mushrooms.

Some of these wild, edible Agaricus have strong and tasty flavor, but some others (not listed here) are poisonous. Smart Kitchen does not advise pursuing wild mushrooms on your own.

Purchasing

Button Mushrooms can be found in most local grocery store in various forms including: Fresh Mushrooms (whole & prepped), Canned Mushrooms and Frozen Mushrooms. Button Mushrooms are not normally sold dried or powdered.

Select young Button Mushrooms in prime condition, with whole, closed, clean, white, caps and no signs of bruising or sliminess. Look under the mushroom cap for the “ring,” the soft covering that joins the edge of the cap to the stem. It should be intact and covering the Gills so that the gills are covered and cannot be seen. If you can see the gills, the mushroom is past its prime.

Because they are very moist (about 90% water), Button Mushrooms should appear and feel “springy,” that is firm and dry, without actually being dry or shriveled. The longer the Button Mushrooms have been sitting on your grocer’s shelf the darker they will be with more brown discoloration.

Aroma can also help you make better Button Mushroom purchasing decisions. Good, fresh Mushrooms will smell earthy. The stronger the earthiness, the more flavor the Mushroom contains. Sour or fishy smelling Mushrooms should be avoided. Mold growth and sliminess are other definite signs that the Mushrooms are bad.

We tend to avoid buying pre-sliced, fresh Button Mushrooms because it is harder to tell how many mushroom caps you are getting. This can be a problem if a particular recipes calls for mushrooms by the count (the certain number of whole mushrooms) not by volume or weight. Also cutting into the product in a factory someplace starts the clock running on moisture loss. We can’t know how long the Mushrooms have been in transit.

Some markets package larger Button Mushrooms together and market them as especially selected for stuffing.

Storage

Within the perishable world of Mushrooms, Button Mushrooms are among the more hardy specimens. Even so, excessive moisture degrades fresh Button Mushrooms and can make them soggy.

When brought home from the store, or farm stand, they should be stored in their original cardboard container on a shelf in the refrigerator. If you want to remove the plastic wrap, if any, and cover the Button Mushrooms with a dry paper towel that is fine. Placing them under wax paper or in a paper bag is good as well.

We don’t recommend using the higher humidity crisper drawer for moisture-sensitive Mushrooms. Stored as described above, Fresh Mushrooms should last about 5-7 days in the refrigerator. Stored at room temperature they will only last a day or so. Because of their moisture content, we don’t suggest freezing fresh Button Mushrooms at home. If you Sauté them first they can be frozen.

If you found a great deal and want to store an abundance of fresh Button Mushrooms, you can Slice them and dry them at home, out or using a dehydrator. Once dried, Dried Mushrooms should be stored in an airtight container in a cool dark place such as a cabinet or pantry. Stored this way they can last up to a year, maybe two. They can last even longer if they are frozen. Don’t forget that Dried Mushrooms will need to be Rehydrated before use.

An apparently older name for this mushroom is Agaricus brunnescens, referring to the oxidative "browning" reaction when the mushroom is bruised. Be careful how you handle them.

Culinary Uses

Button Mushrooms, also known as Open Cap Mushrooms, are sturdy and completely edible* (both Cap & Stalk). Though they are porous, and can pick up surrounding tastes, they can do so without losing their own flavor when cooked. Many chefs think of them as a “universal” Mushroom because they are more forgiving than delicate Mushrooms (Chanterelle Mushrooms or Morel Mushrooms for example) and are easily cooked in almost any recipe that calls for Mushrooms. A secondary reason is because they can be eaten Raw, in moderation. Many national health departments advise against eating more than 4.4 pounds (2 kg) of Raw Button Mushrooms a year.

On Smart Kitchen’s Home Plate Button Mushrooms are Tender, Thin, Moist and Lean (T1, T3, M, L). The actual thickness will depend on how the Button Mushrooms are prepared but the typical Button Mushroom Cap is thinner than one inch. They are moist because they are 90% water and they are lean because they are very low in fat.

Once prepped, Button Mushrooms can be eaten Raw in Salads, Sandwiches, Crudités or Canapés. Raw their flavor is mild but cooking brings out their fragrance and a “meatier” Umami taste. We suggest avoiding eating Raw Button Mushrooms but if you have the need, only eat them in moderation.

We suggest that Mushrooms be cooked for two primary reasons. The first is that Mushrooms can contain small levels of toxins and carcinogens. Cooking heat breaks them down significantly. The second reason is that many of the beneficial nutrients in Mushrooms are locked away behind indigestible chitin in the Mushrooms tough cell walls. Cooking heat weakens the chitin and thus makes the Mushrooms more nutritious.

Cooked Mushrooms can then be eaten by themselves, as a Side Dish, used as a Garnish or added to other already cooked dishes such as Pastas, Hamburgers, Sandwiches, Sauces, and many of the uses listed above for raw Mushrooms.

In the kitchens of America, Button Mushrooms are most commonly found as Pizza Toppings, but you will find them in Quiches, Frittatas, Vol au Vents, Tartlets, CrepesDuxelle, Mushroom Essence, etc., but your imagination is really the only limiting factor.

In Asian Cuisine they are often found Sliced into Miso Soup, in Stir Fry or served Tempura style.

Smart Kitchen’s Recipe Section has a number of Mushroom recipes that work well with Button Mushrooms such as: Crab Stuffed Cremini Mushrooms, Savory Oyster Mushroom Fritters, Batter Fried Oyster Mushrooms, Shiitake Mushroom and Potato Soup, The Hunger Games Mushroom Soup, Oyster Mushroom Baked Rice, Oyster Mushroom Fritatta, Kosher Mushroom Lasagna, Oyster Mushroom Steak Sauce, Mushroom Gravy, Mushroom Clam Bisque, and Kosher Warm Mushroom and Sweet Potato Salad.

* Smart Kitchen only advises using the mushroom Pileus (cap) and the stalk of Edible Mushrooms in the kitchen. They tend to grow above ground and are less likely to harbor, anaerobic Botulism.

Also some people may be allergic to Mushrooms. Use caution when serving them, or when serving someone their first portion of Mushrooms.

Portion Size

Allow 1-2 oz of White Button Mushrooms per person.

Substitutes

Cremini Mushrooms

Nutritional Value USDA
MUSHROOMS,WHITE,RAW
Amount Per 100g
Calories 22
%Daily Value*
 
0%
Total Fat 0g
0%
Saturated Fat 0g
Polyunsaturated Fat 0g
Monounsaturated Fat 0g
0%
Cholesterol 0mg
0%
Sodium 5mg
6%
Potassium 318mg
1%
Total Carbohydrate 3g
4%
Dietary Fiber 1g
Sugars 1g
Protein 3g
* Percent Daily Values are based on a 2,000 calorie diet. Your Daily Values may be higher or lower depending on your calorie needs.
Nutrition

We suggest that Mushrooms be cooked for two primary reasons. The first is that Mushrooms can contain small levels of toxins and carcinogens. Cooking heat breaks them down significantly. The second reason is that many of the beneficial nutrients in Mushrooms are locked away behind indigestible chitin in the Mushrooms tough cell walls. Cooking heat weakens the chitin and thus makes the Mushrooms more nutritious.

Button Mushrooms are low fat and can be a good source of Niacin, Iron, Potassium, Phosphorus, Vitamin B and Vitamin D. In fact, Mushrooms are one of the few natural sources of Vitamin D, but the amount in each Mushroom depends on how much ultraviolet light they have been exposed to as they grow. Most Button Mushrooms only have a small amount, but some Mushroom farmers boost the Vitamin D content by exposing their product to ultraviolet light.

 Mushrooms can be a good source of antioxidants as well. For example, a handful of Button Mushrooms provides twelve times more L-Ergothioneine than Wheat Germ and four times more than Chicken Liver. Protocatechuic Acid and Pyrocatechol are also found in Button Mushrooms.

Overall Button Mushrooms are thought to contain muscle building, acid regulating, immune system boosting, disease-fighting, anti-inflammatory nutrients. Chronic inflammation, to take one case, increases the risks of many health problems, including type 2 diabetes, cardiovascular disease, and certain cancers.

The downside is that eating Button Mushrooms Raw in large quantities may be a cancer risk. Some older studies from the 1990’s show that Button Mushrooms, along with some other edible Mushrooms, contain hydrazine derivatives, including Agaritine (a hydrazine) and Gyromitrin that have demonstrated carcinogenic activity. Administration of uncooked mushrooms to mice, in separate medical studies, caused a marked increase in the number of bone, stomach, and lung tumors in the rodents. Cooking does significantly reduce the carcinogenic compounds and in fact, may help turn the mushrooms into a cancer fighter through apoptosis.

Studies at the Beckman Research Institute of the City of Hope in Duarte, California, suggest that white button mushrooms contain an important cancer-fighting substance called conjugated linoleic acid (CLA). CLA minimizes the effects of the enzyme aromatase, which reduces risks posed by high estrogen levels.

Other studies show a direct relationship between the consumption of fresh mushrooms and a declining rate of breast and prostate cancer growth, as well as the suppression of a compound believed to play a role in cancer tumor development.

Gluten Free

Yes

Low Fat

Yes

Low Calorie

Yes