HomeMyco

A homebrewer's take on practical home cultivation of mycelium and their mushrooms.

Always a Risk of Contamination

Contamination occurs when another microorganism takes advantage of the gratuity you provide for your mycelium. There is always a risk of bacterial and mold contamination when it comes to mycelium.

While many guides do everything they can to reduce this risk, my approach is to make the methods quick, cheap, and simple. Contaminated spawn is easily discarded and replaced.

Do It Thrice

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

• When making colonization jars make at least two for each sample we wish to colonize.

• When making agar slants or liquid cultures make at least two for each sample.

• Make and save at least one of the above as a control for testing your sanitation.

It is OK. Seed spawn, agar, and sugar water are inexpensive.

Saving a control spawn medium, both grain spawns and culture mediums, will help you test for contamination introduced through your technique. If all fares well you can always end up using it.

Finding Samples

• mycelium sample

At the beginning of each section is a checklist of what to buy. At the end of the document there will be a combined checklist.

Newbies should start with store bought mushrooms. This will allow you to walk through the methods without fear of wasting a sample. Getting other samples should not be difficult but it is quite frustrating to discover all if the sanitary steps were made in vain when a contaminated sample was the source. Of course, there is always the risk of a contaminated store bought sample.

Online shopping can get you all sorts of 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 the spores of your harvested mushrooms.

Sanitize Your Workspace

• empty spray bottles, chemical resistant
• star san, sanitizer

Prior to working with a mycelium sample or spawn medium you should clean your work area. All surfaces and tools should be wiped clean then sprayed with a sanitizing solution at least 2 minute prior to working.

Purchase a spray bottle 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.

If you are working near your living space a food safe sanitizer like Star San avoids stinking up the place or contaminating food. It is very concentrate so just a couple drops into a spray bottle full of water be 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 sanitization is not sterile. Star San does not kill all bacteria or mold. There is always a risk of contamination.

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

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

Scrub your hands with warm water and soap to remove anything that might fall off into the spawn medium. Avoid touching your spawn medium and 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 the look pretty cool when they do.

Three Stages

There are three general stages to cultivating mycelium.

1. Culturing, wiki

   • Using simple sugar and agar as a surface to proof sample 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 grain spawn to promote the growth of mushrooms.

Culturing

Any sample of mycelium is potentially contaminated. Aside from using a microscope and checking the entire sample, using a small culture will allow you to grow a test patch of your sample without risking a whole jar of grain spawn.

The two culture mediums preferred are agar slants and liquid cultures together.

While petri dishes are part of the usual trappings of cultivating the growth of microorganisms they are fairly high maintenance and better suited for a laboratory environment. Agar slants provide the same functionality without the need to seal and re-seal with parafilm.

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 being unable to isolate mycelium from contaminations.

You should use agar slants to isolate mycelium from contamination then sample the mycelium from the agar to liquid culture.

Culture Mediums

• food scale, grams
• 16 oz wide mouth mason jars with lids
• distilled water
• 50 to 100 ml syringe with hollow needle, autoclavable
• 30 to 50 ml test tube with screw cap, autoclavable
• electric pressure cooker, stove top, or autoclave

Agar Slants

• malt extract agar

Agar agar is a plant gelatin used to provide a physical surface that mycelium can colonize. This is mixed with a simple sugar like malt extract to provide mycelium calories for reproduction. Malt Extract Agar (MEA) is available in a premix fairly cheap online. Mixing 2:3 grams ratio simple sugar to Agar powder is good for saving money in bulk.

Scale the following recipe as needed to fill 1/3 of each test tube or 10 ml:

0. Sanitize Your Workspace.

1. Fill a 16 oz mason jar with 100 ml water on a food scale.

   • Grams is the same as milliliters of water at STP.

2. Microwave with a safe cover for 1 minute or until 50 celsius or higher without boiling.

3. Add 5 grams of MEA to warm water and stir for 1 minute with a sanitary utensil.

4. While the MEA solution is still warm, fill a sanitary syringe with the solution.

5. Fill a sanitary test tube one third (1/3) capacity and replace the screw cap.

6. Place test tubes in an empty mason jar and autoclave for 1 hour.

7. Carefully remove each test tube and place on a flat surface with the screw cap slightly elevated on a dish towel.

   • Once cooled the agar should solidify into a slanted surface for inoculation.

8. Store in a dark cool place until inoculation. Do not freeze.

Liquid Cultures

• light corn syrup

Mixing liquid culture is similar to agar slants without needing to cool in any particular position. A simple sugar like light corn syrup is dissolved in distilled water to provide mycelium calories for reproduction.

Scale the following recipe as needed to fill 2/3 of each test tube or 20 ml:

0. Sanitize Your Workspace.

1. Fill a 16 oz mason jar with 100 ml water on a food scale.

   • Grams is the same as milliliters of water at STP.

2. Microwave with a safe cover for 1 minute or until 50 celsius or higher without boiling.

3. Add 5 grams of light corn syrup to warm water and stir for 1 minute with a sanitary utensil.

4. Fill a sanitary syringe with the solution.

5. Fill a sanitary test tube one third (2/3) capacity and replace the screw cap.

6. Place test tubes in an empty mason jar and autoclave for 1 hour.

7. Store in a dark cool place until inoculation.

8. Once inoculated, shake the test tubes daily to oxygenate the water and break up the mycelium.

Autoclave

Autoclave is a generic term for a pressurized steam chamber for sanitization 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), reduce the time by 1/3.

Autoclavable tools are safe to bring to 250 celsius for extended durations without damage.

Use the following durations as they make sense to sanitize and pasteurize.

• 2 hours

  • Spawn grain should be autoclave for 2 hours prior to inoculation. Bulk grains are particularly susceptible to contamination during the commercial farming process.

• 1 hour

  • Cultures do not need to autoclave for as long as spawn grain since there is less volume that needs to get to temperature.

  • Add your autoclavable tools if there is space. If you do not plan to use them soon after autoclave, soak in Star San solution and store covered.

• 10 minutes

  • Quickly bring test tubes and tools to temperature for cleaning out old agar or liquid culture.

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

1. Add 200 ml of water.

2. Insert items to be autoclave.

3. Press Steam option and set the appropriate time.

4. Turn vent valve to close.

5. Quick release once time has completed if needed, working with agar warm is easier.

Culture Inoculation

Once you autoclave your culture mediums 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 store bought mushrooms. This will allow you to walk through the methods without fear of wasting a spore sample.

Cloning

• paring knife or scalpel

Taking a mycelium samples from the stem of a mushroom is called cloning.

The collection of a sample for cloning is relatively trivial using a syringe with a hollow needle.

0. Sanitize Your Workspace.

   • Sanitize the outside of each culture medium.

1. With a sanitary knife, cut the stem off the mushroom then half down the length.

2. Using the hollow needle tip of the syringe, plunge along the length of the stem collecting a sample of the core of the stem.

3. Gently use air pressure from the syringe will push the sample into an open culture medium.

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

Spore Samples

• inoculation loop

• 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 further be added to a syringe of sterile water for ease in shipping.

In either case, an inoculation loop is used to apply the spore samples to a culture medium.

Spore Print

0. Sanitize Your Workspace.

   • Sanitize the outside of each culture medium.

1. Using a lighter, heat the loop element of your inoculation loop until it glows red. Allow the loop to cool.

2. Scraped spores off a print delivery medium with a sterile sharp.

3. Collect spores on the loop.

4. Insert loop into an open culture medium and gently apply spores.

5. Replace the screw cap on the culture medium and store in ambient room light at room temperature.

Spore Syringe

0. Sanitize Your Workspace.

   • Sanitize the outside of each culture medium.

1. Using a lighter, heat the loop element of your inoculation loop until it glows red. Allow the loop to cool.

2. Place a single drop of water from a spore syringe on the loop.

3. Insert loop into an open culture medium and gently apply spores.

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

Wood Plugs

• tweezers

Mycelium samples are often sold as colonized grain or wood plugs. Usually these can be used to inoculate grain spawn directly but we can also make cultures to store these samples long-term.

With sanitary tweezers place a sample in an agar slant, liquid culture, or grain spawn.

Reading an Agar Slant

Agar slants should show growth within the first week and should be monitored for contamination weekly.

Mycelium are snowy white with grey and blue tints as normal.

Any other colors and you are dealing with contamination. Contamination is not the end of the world. Mycelium can be isolated from a contaminated sample.

If enough mycelium growth has occurred that a sample can be collected without touching the contamination then it can be transferred to a fresh culture medium.

0. Sanitize Your Workspace.

   • Sanitize the outside of each culture medium.

1. Using a lighter, heat the loop element of your inoculation loop until it glows red. Allow the loop to cool.

2. Gently scrape some of the mycelium onto the loop.

3. Insert loop into an open culture medium and gently apply spores.

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

Colonization

Once the mycelium has been successfully isolated and grown in a liquid culture 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 wood chips. This guide does not address these special requirements. I leave it up to you to research your mycelium species.

Grain spawn is a common source of nutrients and the most accessible source of grain spawn is wild bird seed.

Grain Spawn

• 16 oz wide mouth mason jars with lids
• wild bird seed with millet
• colander
• ladle
• boiling pot
• aluminum foil
• electric pressure cooker, stove top, or autoclave

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

0. Sanitize Your Workspace.

1. Fill 16 oz wide mouth mason jars with 1 cup of bird seed per final jar of grain spawn.

2. Cover bird seed with tap water, lid jar, and soak for 12 to 24 hours.

3. Strain the bird seed with a colander and rinse with water.

   • Pick out any unwanted bits like twigs or mush.

4. Bring a pot of water to a rolling boil.

5. With a ladle, carefully add one scoop at a time to the boiling water.

6. Once all the bird seed is added let the water return to a boil.

7. Strain again with a colander for 1 hour to dry, stirring occasionally.

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

9. Cover un-lid jars with aluminum foil and autoclave for 2 hours.

10. Carefully screw lid over the foil and jar and allow to cool to room temperature.

11. Store in a dark cool place until inoculation.

Spawn Inoculation

• 50 to 100 ml syringe with hollow needle, autoclavable

0. Sanitize Your Workspace.

   • Sanitize the outside of each jar of grain spawn and liquid culture.

1. With a sanitary syringe extract 1 ml of liquid culture and replace the screw top.

2. Inject the liquid culture into the jar of grain spawn by piercing the aluminum foil straight down along the side of the jar.

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

4. Store in ambient room light at room temperature.

Reading a Spawn Jar

Similar to Reading an Agar Slant, grain spawn should show growth within the first week and should be monitored for contamination weekly until it is fully colonized, 2-3 weeks.

Mycelium are snowy white with grey and blue tints as normal.

Any other colors and you are dealing with 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.

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 with a spray bottle and a light breeze.

This can be accomplished with an open and fully colonized grain spawn jar and a daily spray bottle misting.

However, if there is more surface area for the mushroom pins to sprout from then there is a higher chance of successful fruiting.

Fruiting Chamber

• medium plastic tubs with lids
• coconut coir
• personal fan

Coconut husk (coir) as casing layer and flooring in our fruiting chamber to hold moisture better than the mycelium cake we created in the grain spawn jar.

0. Invert an open and fully colonized grain spawn jar and firmly but gently tap cake out.

   • If the cake breaks up that is OK, place the pieces back together if possible.

1. Soak the mycelium cake in water for 12 to 24 hours.

2. Soak coconut coir brick following the packaging for the amount of water, about 15 minutes.

3. Gently roll the mycelium cake in the hydrated coconut coir to form a light casing.

4. Layer the bottom of the tub with an inch or more of coconut coir.

5. Place the mycelium cake on the layer of coconut coir away from the sides.

Daily

The goal is to maintain a 90% humidity within the fruiting chamber.

0. With a water spray bottle gently mist the coconut coir and mycelium cake until the coir is moist but not soaked.

1. Place the medium plastic tub lid upside down, slightly ajar, and rest for 1 hour.

2. Point a personal fan nearby to blow towards the ceiling above the tub for 1 hour.

3. Replace the lid upside down and slightly ajar.

4. Harvest mushrooms before they dump their spores.

Checklist

• mycelium sample

• empty spray bottles, chemical resistant

• star san, sanitizer

• food scale, grams

• 16 oz wide mouth mason jars with lids

• distilled water

• 50 to 100 ml syringe with hollow needle, autoclavable

• 30 to 50 ml test tube with screw cap, autoclavable

• electric pressure cooker, stove top, or autoclave

• malt extract agar

• light corn syrup

• paring knife or scalpel

• inoculation loop

• flame or lighter

• tweezers

• wild bird seed with millet

• colander

• ladle

• boiling pot

• aluminum foil

• medium plastic tubs with lids

• coconut coir

• personal fan