While many don’t think about the common mushroom too much, it is certainly a wonder of the fungiculture world! While this mushroom is only one species, Agaricus bisporus, many people think it’s various life stages are separate mushrooms!
The Common mushroom is known as white or button mushrooms during it’s adolescence. As it grows it becomes brown on top and is often commercially available as cremini or baby bella mushrooms. Once fully grown the mushrooms are marketed as portobello mushrooms.
This mushroom’s ability to be commercially viable and safe to eat at all stages of it’s life cycle makes it a staple in the industry and has earned it the moniker of the common mushroom.
Habitat, Distribution, and Wild Growth
Another thing that makes this mushroom so common is that it is found world wide naturally from late spring to early fall. In many parts of the world it is collected and eaten from the wild. Like many mushrooms it like humid cool conditions, but being so common there are varieties that are much more tolerant to weather changes and grow in all sorts of odd places.
This mushroom is a manure loving variety and often grows in areas where there will be ample amounts of nutrients for it, such as fields and pastures where animal roam freely.
Appearance and Morphology
Throughout it’s life cycle the mushroom changes size shape and color. Initial adolescent mushrooms are small white caps. As they age they develop a dark brown top and open their caps fully to flatten out with maturity. The gills of this mushroom change from light pink to a dark brown as it ages due to the dark brown color of its spores.
The adolescent forms, or button mushroom, is typically picked while the mushroom is about an inch in diameter. The adult portobello mushroom can grow to 4 inches in diameter.
Taste and Cooking
The common mushroom is what many people ascribe the basic mushroomy taste to. Much like chicken is the staple meat to compare other meats to, the common mushroom is the standard in the fungi world. If you’ve never had a common mushroom before, they have a mild earthy taste and pair well with a variety of flavors.
The common mushroom is so common that it has been used in just about every type of food you can imagine. It’s as at home on a pizza as it is raw on a salad.
Nutritional Value of The Common Mushroom
The common mushroom is a good source of many nutrients and a decent source of protein. They contain a variety of B vitamins, as well as many bio-available minerals such as iron, phosphorus, potassium, and zinc. Because of it’s relatively high nutritional value and low fat and sugar count, the common mushroom is a healthy choice in most diets. Additionally, unlike other mushroom species, the common mushroom poses no natural toxicities in either its raw or cooked forms when eaten in normal amounts.
Look Alike Mushrooms
While the common button mushroom is safe to eat and can be found in the wild, it’s young form looks very similar to the destroying angel mushroom which is extremely deadly if eaten. The destroying angel is a spruce symbiote so avoid collection mushrooms around spruce or wooded areas if you are not certain about their nature.
Another look alike mushroom that grows in grassy areas is Agaricus xanthodermus. This mushroom is inedible and if eaten will cause nausea and vomiting in some people. The mushroom smells like phenol and it’s flesh turns yellow when bruised, so it’s easier to identify, but this is still something to look out when harvesting mushrooms in the wild.
Agaricus bisporus is the most commonly cultivated mushroom world wide, being farmed in at least 70 countries. It’s a top choice for fungiculture because it is hearty, easy to grow, resists contamination, and has multiple commercially viable stages with no toxicity.
Historical Cultivation of the Common Mushroom
While the earliest know cultivation of the common mushroom started in 1707, it wasn’t until the late 1800s that cultivation techniques were improved to the point of consistent growth and output. The change in technique can be credited directly to Louis Pasteur’s name sake research foundation, The Pasteur Institute, where sterile technique and manure cultivation for mushrooms was refined.
Modern large scale common mushroom cultivation is down to a science now. It has been refined over the years, but it is still the least susceptible process to contamination due to the species and improved technique.
Modern common mushroom cultivation starts with compost substrate creation. The typical mix is made in an industrial compost turner which wets and rotates the mixture. It contains ingredients like horse manure, straw, supplemental nitrogen and gypsum. The compost ages under normal aerobic fermentation conditions. In large scale setups most farms will use forced aeration rather than manual aeration techniques to avoid anaerobic fermentation.
Mushroom compost is developed through microbial activity. While many other cultivated mushrooms need a sterile, uncomposted starting medium, the common mushroom has nutritional requirements that rely on other microbes to make compounds they will later need for growth. While this process is microbe heavy, it is important to start with quality materials to reduce the chance of introducing contaminants that could hurt or compete with the mushrooms.
When finishing the compost the whole bulk is pasteurized. This kills insects, nematodes, and other microbes that might compete with the mushroom spawn, but leaves behind nutrients and helpful microbes which can survive the process. Additionally the compost is treated to remove excess ammonia, which is a fungal growth inhibitor.
Once the compost is ready it’s added to large box trays. These trays get inoculated with mushroom grain spawn, typically as they are being filled or just after using a specialized machine. After this process the trays are finished with any other supplemental nutrients that will help increase mushroom yeilds and a top cover layer. The top layer is often refereed to as casing and is typically comprised of peat moss and limestone, this layer acts as a water reservoir to keep the bed moist.
After all this it’s time to let the mushrooms grow! The process proceeds from around 18-21 days until mushrooms form completely. Depending on the setup, mushroom pinning is regulated through ventilation as it was determined that it only occurs when CO2 levels are under approximately 0.04 percent. Because of this ventilation should only occur once a bulk of the mycelium has grown and can be seen permeating the the top casing.
Harvesting of fresh flushes can occur repeatedly every 3 to 5 days and last for up to 150 days in modern commercial environments. That’s a lot of mushrooms! The many mushrooms are stored in breathable containers and shipped to various locations for further packaging and distribution. Harvesting conditions for the common mushroom do not require a clean room or sterile technique as the mushrooms are often strong enough to resist most common pests once they colonize a tray fully.
The common mushroom can be grown at home easily and without any complicated equipment. Detailed instructions on this process can be found here. While you may not have access to the latest and greatest in technology, these mushrooms are easy enough for most beginners and so long as you start with pasteurized compost you will likely be able to get a simple tray growing without much risk of contamination.
Home grown mushroom trays have variable lifespans, but it is possible to continue to spread your grain spawn and essentially keep your mushrooms growing in new trays year after year. Once setup and if managed properly, you can easily maintain a small mushroom garden that will provide you with more than you need continually.