You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

20 KiB

HomeMyco

A homebrewer's take on practical home cultivation of mycelium and their mushrooms. Mycelium are kind of like a mushroom's roots but this is not an exact analogy. The purpose of a mushroom is to release spores as far away from the colony as it can reach.

Creative Commons Attribution-NonCommercial-ShareAlike 4.0

There is Always a Risk of Contamination

Contamination occurs when other microorganisms take advantage of the gratuity you provide for your mycelium. There is always a risk that bacteria and mold will invade, competing with your precious mushroom makers.

Many guides do everything they can to reduce this risk. My approach gives you methods that are still effective but easy and cheap to recover from contamination.

Do it Thrice

As a result of the above hubris we triple our efforts.

  • Make at least two liquid cultures for each sample we wish to test.

  • Make at least two colonization jars for each sample we wish to colonize.

  • Make one extra liquid culture and colonization jar as a control for testing your sanitation.

Bird seed, coconut husk, and sugar water are inexpensive. All other equipment can be reused. Saving a control will help you test for contamination introduced through your technique. If all fares well you can always using it the next time you do inoculations.

Finding Samples

  • mycelium sample

Each section starts with a checklist of what to buy. The end of this document has a combined checklist.

Newbies should start with grocery store mushrooms. This will allow you to walk through the methods without fear of wasting a sample. Finding other kinds of mycelium samples is not particularly difficult but it is frustrating to discover all the sanitary precautions were made in vain when a contaminated sample was the source. There remains the risk that grocery store mushrooms are contaminated.

Online shopping can get you all sorts of mycelium sample types, ranging from spawn grains and liquid culture to spores and dried mushrooms. When paying good money for a sample try to find liquid culture as they have a pretty good colonization rate.

Eventually you will want to make your own cultures from your harvested mushrooms.

Three Stages

There are three general stages to cultivating mycelium.

  1. Culturing, wiki

    • Using simple sugar solution to test a sample of mycelium for viability and contamination.
  2. Colonization, wiki

    • Using grain as food source to promote mycelium growth throughout.
  3. Fruiting, wiki

    • Apply the ideal conditions to fully colonized seed grain to promote the growth of mushrooms.

Sanitize Your Workspace

  • empty spray bottles, chemical resistant

  • star san, sanitizer

The critical time to practice good sanitation is when opening any of your containers and interacting with the spawn medium inside. Spawn medium refers to any nutrient rich growing surface, such as seed grain or simple sugar.

Clean yourself and work area before working with a mycelium sample or spawn medium. All surfaces and tools should be wiped clean then sprayed with a sanitizing solution to soak for at least 2 minute prior to working.

Purchase a new spray bottle that is resistant to chemical reactions for this purpose. These can be found at most hardware stores. While you are at it you should buy a second spray bottle for misting water during the fruiting stage.

If you are working near your living space then a food safe sanitizer like Star San to avoid stinking up the place or contaminating food. It is very concentrate, a couple drops into a spray bottle full of water is enough. You will know if the solution is diluted enough when it sprays easily and creates small bubbles on the sprayed surface.

It is important to note that sanitation is not sterile. Star San does not kill all bacteria or mold. There is always a risk of contamination.

If you have a way to vent your workspace or won't bother anyone else with the fumes you can use 70% isopropyl alcohol instead of star san.

Your face, hands, and tools are the major source of contamination. Tools can be sterilize in a pressure cooker or autoclave. Your face, hand, and the other hand are a little more difficult to contain.

While gloves and a face mask are often recommended, they may be more clumsy to the point of negating any benefit they might provide. Face masks do not work unless they provide respiration filtering. Gloves only work if they begin sterile and remain sterile.

Scrub your hands and forearms with warm water and soap to remove anything that might fall into the spawn medium. Avoid touching your spawn medium directly. Avoid touching the part of your tools that interact with the spawn medium.

Wash and dry your face with warm water and soap to remove anything that might fall off into the spawn medium. Combing your hair and wearing a hat helps to reduce the amount of lose hair that might fall into the spawn medium. Slow or hold your breath when inoculating spawn medium to avoid shaking.

Remember that mistakes happen and they look pretty cool when they do.

Mycelium Cultures

A clean sample of the mycelium you wish to cultivate must be obtained to begin growing the mycelium colonies which produce mushrooms.

Any samples of mycelium are potentially contaminated. Even using a microscope and visually checking the entire sample is tedious, error prone, and impractical. A small culture will allow you to grow a test batch of your sample without for a jar of grain spawn to show signs of contamination.

The preferred culture medium is liquid cultures. Liquid cultures provide a similar micro climate as agar slants with the added benefit of being a much easier for inoculating grain spawn. The disadvantage of liquid culture is they are a little difficult to identify contamination.

You may use agar slants to isolate mycelium from contamination before transferring to liquid cultures. This guide does not cover their use. Skipping testing on agar slants works well enough as long as you give liquid cultures extra time for bacteria to become visible while suspended in water.

Liquid Cultures

A simple sugar like light corn syrup is dissolved in distilled water to provide mycelium calories for reproduction.

  • food scale, grams

  • 16 oz wide mouth mason jars with lids

  • 50 to 100 ml syringes with hollow needles, autoclavable

  • distilled water

  • light corn syrup

  • marbles or magnetic stirring rods

  • aluminum foil

  • electric pressure cooker, stove top, or autoclave

Imperial Metric
16 oz 450 ml
Ingredient Mason Jar Ratio
water 300 ml 100 ml
simple sugar 15 g 5 g
  1. Sanitize Your Workspace.

  2. Fill each 16 oz mason jar with 300 ml water on a food scale.

    • Grams is the same as milliliters of water at STP.
  3. Microwave with a safe cover until boiling, about 1 minute.

  4. Add 15 grams of light corn syrup to warm water.

    • Optionally add no more than 1 gram of diammonium phosphate (dap) with urea for yeast nutrients.
  5. Insert a marble or magnetic stirring rod for stirring the solution once inoculated.

  6. Cover jar opening with aluminum foil and pressure cook for 25 minutes at 70 kPa (10 psi). Allow to cool to room temperature.

  7. Replace aluminum foil with mason jar lid, screwing closed tightly to prevent spilling.

  8. Store in a dark cool place until inoculation.

  9. Daily shake the mason jars daily to release carbon dioxide and oxygenate the water. Unscrew the cap and slightly lift the lid to allow the carbon dioxide to escape.

Autoclave

Autoclave is a generic term for pressurized steam chambers for sanitation and sterilization.

All autoclave duration measurements use electric pressure cookers for convenience.

If you have a stove top pressure cooker or industrial autoclave that provide a continuous 100 kPa (15 psi), you may reduce the time by 1/3 for grain spawn.

Autoclavable tools are safe to bring to 120 celsius for extended duration without damage.

  1. Add the steam rack to the inner pot of the electric pressure cooker.

  2. Add 200 ml of water to the inner pot.

  3. Insert items to be autoclave on to the steam rack.

  4. Press Steam or Canning option and set the appropriate time.

  5. Turn vent valve to close.

  6. Once time has completed allow to passively depressurize.

Culture Inoculation

Once you autoclave your liquid cultures and they have cooled to room temperature it is ready for mycelium.

Depending on the source of the sample there are two ways to inoculate, cloning from a mushroom or using spore samples. Newbies should start with cloning grocery store mushrooms. This will allow you to walk through the methods without fear of wasting a spore sample.

Cloning

Taking mycelium samples from mushroom tissue is called cloning. Piercing the mushroom tissue with a hollow needled syringe is enough to collect a sample.

  1. Sanitize Your Workspace.

  2. Cut the stem off the mushroom with a sanitary knife.

  3. Pull the plunger of a sanitary syringe to halfway out.

  4. Plunge a hollow needle tip of the syringe into the center along the length of the stem to collect a small sample.

  5. Gently push the plunger on the syringe to use air pressure to put the sample into an open liquid culture.

  6. Replace the screw cap on the liquid culture and store in ambient room light at room temperature.

  7. Daily release the pressure within the liquid culture container by unscrewing the cap.

Spore Samples

  • flame or lighter

Spore samples are created by placing a mushroom cap on a flat surface and collecting the spores that are released. These are called spore prints. Spores can then be added to a syringe of sterile water for ease in shipping.

Spore Syringe

  1. Sanitize Your Workspace.

  2. Using a lighter, heat the spore syringe needle until it glows red. Allow to cool.

  3. Place a single drop of water from a spore syringe on the liquid culture.

  4. Replace the screw cap on the liquid culture and store in ambient room light at room temperature.

Spore Print

An inoculation loop maybe useful to apply the spore print samples to a liquid culture. Alternatively use a sanitary sharp knife or scalpel to apply the spore print samples.

  1. Sanitize Your Workspace.

  2. Lightly scrape spores off a print delivery medium with a sanitary sharp.

  3. Heat the loop element of the inoculation loop using a lighter until it glows red. Allow the loop to cool.

  4. Collect spores on the loop by gently rubbing against the loose spores.

  5. Insert loop into an open liquid culture and gently apply spores.

  6. Replace the screw cap on the liquid culture and store in ambient room light at room temperature.

  7. Daily release the pressure within the liquid culture container by unscrewing the cap.

Reading Liquid Cultures

Liquid cultures should show growth within the first week after inoculation and should be monitored for contamination weekly.

Mycelium are snowy white with grey, blue, or brown tints depending on the species.

Colors like yellow, red, green, and black usually indicate contamination.

Dispose of the contaminated solution being mindful of any stirring rods or marbles you might have inserted.

Colonization

Once the mycelium is successfully isolated in liquid cultures, the mycelium wants something a bit more nutritious than sugar water. Most species have special requirements that encourage the growth of mushrooms. Wood-loving species like oyster and shiitake thrive in a mixture of sawdust. This guide does not address these special requirements. I leave it up to you to research your mycelium species.

Mushroom growers have had some success with the much quicker method of inoculating store bought sterilized whole brown rice. These are usually sold as:

Instant Microwavable Whole Grain Brown Rice

For your first time I recommend store bought sterilized whole brown rice to learn the process without worrying about contaminated grain. Simply cut a small hole in a corner of the sterile container and follow the instructions for spawn inoculation. Tape the small hole closed.

You should, however, provide mycelium a variety of grain spawn and substrate between generations of colonies so the strain does not lose it's ability to digest different sources of nutrition. These general instructions are the same for most grain spawn but the most accessible source of grain spawn is wild bird seed.

Grain Spawn and Substrate

Nutrient rich grain treated and sanitized to feed mycelium. Vitamin and mineral rich substrate treated and sanitized to provide mycelium a growing surface.

  • 16 oz wide mouth mason jars with lids

  • wild bird seed with millet

  • coconut coir

  • food bucket and lid

  • aluminum foil

  • electric pressure cooker, stove top, or autoclave

Imperial Metric
16 oz 450 ml
1 cup 250 ml

Wild bird seed is dusty and full of bacteria and molds. Because the seeds are dry the bacteria has likely endosporulated, making it resistant to sanitization. Soaking the bird seed will clean it up a bit and encourage the endospores to reproduce, leaving them weaker to autoclave.

Earlier it was mentioned that mycelium want a variety of grain spawn and substrates between generations of colonies so the strain does not lose it's ability to digest different sources of nutrition.

This guide uses coconut husk (coir) mixed with grain spawn for colonization as a substrate. You can also add coffee grounds, sawdust, straw, and rice husks for variety. Take caution to only change one thing at a time between generations or you risk overwhelming the mycelium.

Be mindful of commercial gardening coir as they are treated with endophyte to protect plant roots. These endophytes do not protect our mushroom roots and will compete for resources like any other contamination.

  1. Sanitize Your Workspace.

  2. Hydrate the coconut coir brick following the packaging instructions.

  3. Mix the coconut coir and wild bird seed in the bucket at a 50/50 ratio.

  4. Fill with water until moisture is visible on the surface of the mixture and soak overnight.

  5. Split evenly to each 16 oz wide mouth mason jar, about 1 cup.

  6. Cover jar opening with aluminum foil and pressure cook for 2 hours.

  7. Lightly screw lid over the foil to secure it in place without sealing the jar and allow to cool to room temperature.

  8. Store in a dark cool place until inoculation.

Spawn Inoculation

  1. Sanitize Your Workspace.

  2. Gently stir the liquid culture and with a sanitary syringe extract 1 ml of liquid culture, replace the screw top.

  3. Inject syringe into the jar of grain spawn by carefully piercing the aluminum foil straight down along the inside of the jar.

  4. Replace the mason jar lid by flipping it so the seal is facing up and lightly screwing on the rim.

  5. Store in ambient room light at room temperature.

Reading a Spawn Jar

Similar to reading liquid cultures, grain spawn should show growth within the first week after inoculation and should be monitored for contamination weekly until it is fully colonized, 2-3 weeks.

Mycelium are snowy white with grey, blue, or brown tints depending on the species.

Colors like yellow, red, green, and black usually indicate contamination. Minor contamination is not the end of the world, many colonies can recover.

If the jar is fully colonized following a contamination and doesn't smell like rotten apples it can still produce mushrooms.

Once the grain and substrate in the jar is covered with feathery white mycelium, give it one more week before fruiting.

Fruiting

If you've ever been walking in the woods after a light rain you've probably seen mushrooms peaking up. This is because mycelium sense that water is evaporating and wish to take advantage of the updraft to spread their spores.

In our fruiting containers we want to mimic that as much as possible without exposing the substrate to contamination.

The mushrooms are light sensitive, to prevent them grow inside the jar we cover the glass with aluminum foil.

Fruiting Chambers

  • clear plastic tubs with lids, shoebox or larger

  • hygrometers

Once the top surface of the coconut coir has been covered by feathery white mycelium it is ready to fruit.

  1. Cover the glass mason jars with a sheet of aluminum foil, remove lid exposing the colony to the air.

  2. Place jar within a clear plastic tub with the jar on its side.

  3. Place a sanitary hygrometer onto the tub where it is visible.

  4. Once tub is full of sideways open jars, replace tub lid and store in ambient room light at room temperature.

Daily

Try to maintain at least 80% humidity within the fruiting chamber. The water soaked coconut coir should provided more than enough moisture to keep the inside of the clear plastic tubs humid.

If needed, gently mist the fruiting chamber with a spray bottle of distilled water until humid.

Each mushroom is different but in general mushrooms should harvest right when their gills are exposed but before they dump their spores and make a mess.

Checklist

  • mycelium sample

  • empty spray bottles, chemical resistant

  • star san, sanitizer

  • food scale, grams

  • distilled water

  • 16 oz wide mouth mason jars with lids

  • 50 to 100 ml syringes with hollow needles, autoclavable

  • electric pressure cooker, stove top, or autoclave

  • light corn syrup

  • marbles or magnetic stirring rods

  • flame or lighter

  • wild bird seed with millet

  • food bucket and lid

  • aluminum foil

  • coconut coir

  • clear plastic tubs with lids, shoebox or larger

  • hygrometers