HomeMyco

A homebrewer's take on practical home cultivation of mycelium and their mushrooms. You don't have to follow every step in this guide but you should because it's fun.

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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 contaminated spawn.

Do It Thrice

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

• Make at least two agar slants or 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 of the above as a control for testing your sanitation.

It is OK. Bird seed, agar powder, 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 end up using it.

Spawn medium refers to any nutrient rich growing surface, such as grain spawn or culture mediums.

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.

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.

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 with 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 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 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.

Three Stages

There are three general stages to cultivating mycelium.

1. Culturing, wiki

   • Using simple sugar and agar as a surface to test 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 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.

Agar gives mycelium and contamination a surface to grow in large enough colonies to view with the naked eye. A week of growth is usually long enough to produce colonies which can be identified and transferred to liquid cultures. While petri dishes are part of the usual trappings of cultivating 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.

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 contaminations.

You may use agar slants to isolate mycelium from contamination before transferring to liquid cultures. 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.

Culture Mediums

• food scale, grams

• distilled water

• 16 oz wide mouth mason jars with lids

• electric pressure cooker, stove top, or autoclave

• aluminum foil

imperial	metric
16 oz	450 ml

Liquid Cultures

• light corn syrup
• diammonium phosphate with urea (optional)

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

ingredient	mason jar	ratio
water	300 ml	100 ml
simple sugar	15 g	5 g

0. Sanitize Your Workspace.

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

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

2. Microwave with a safe cover until boiling, about 1 minute.

3. Add 15 grams of light corn syrup to warm water and stir for 1 minute with a sanitary utensil.

   • Optionally add no more than 1 gram of diammonium phosphate (dap) with urea for yeast nutrients.

4. Cover un-lid jar opening with aluminum foil and autoclave for 1 hour.

5. Allow to cool and replace aluminum foil with mason jar lid, screwing closed tightly to prevent spilling.

6. Store in a dark cool place until inoculation.

7. Once inoculated, shake the mason jars daily to oxygenate the water and break up the mycelium.

Agar Slants

• agar

• light malt extract

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

• 50 to 100 ml syringe with hollow needle, autoclavable

Agar agar is a plant gelatin that solidifies at room temperature, providing a physical surface that mycelium to colonize. When mixed with a simple sugar like malt extract this provides mycelium calories for reproduction. Malt Extract Agar (MEA) is available premixed fairly cheap online. Mixing 2:3 grams ratio of malt extract to agar powder is good for saving money by buying in bulk from a homebrew shop.

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

ingredient	mason jar	ratio
water	300 ml	100 ml
agar	9 g	3 g
malt extract	6 g	2 g

0. Sanitize Your Workspace.

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

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

2. Microwave with a safe cover until boiling, about 1 minute.

3. Add 9 g of agar and 6 g of malt extract to the warm water and stir well 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.

Autoclave

Autoclave is a generic term for pressurized steam chambers 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), you may 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.

10 minutes	Quickly bring test tubes and tools to temperature for cleaning out old agar or liquid culture.
1 hour	Cultures have less volume to get to temperature. Add your autoclavable tools if there is space.
2 hours	Bulk grains are particularly susceptible to contamination during the commercial farming process.

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

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

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

3. Press Steam option and set the appropriate time.

4. Turn vent valve to close.

5. Once time has completed allow to passively depressurize. Venting the valve early may be necessary for working with agar.

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 cloning grocery store mushrooms. This will allow you to walk through the methods without fear of wasting a spore sample.

Cloning

• paring knife or scalpel

• 50 to 100 ml syringe with hollow needle, autoclavable

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

0. Sanitize Your Workspace.

   • Sanitize the outside of each culture medium.

1. With a sanitary knife, cut the stem off the mushroom.

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

3. Using the hollow needle tip of the syringe, collecting a sample of the core by plunging into the center along the length of the stem.

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

5. 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 then be added to a syringe of sterile water for ease in shipping.

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 to heat the loop element of the inoculation loop until it glows red. Allow the loop to cool.

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

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

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. Cultures are used to store these samples long-term.

Use sanitary tweezers to place a sample in spawn medium.

Reading an Agar Slant

Agar slants should show growth within the first week after inoculation 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. If enough mycelium growth has occurred that a sample can be collected without touching the contamination then it can be transferred to fresh agar slants and tested again. Otherwise, a successful agar slant colony is used to create liquid culture.

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 off of the surface of agar onto the loop.

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

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

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.

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

imperial	metric
16 oz	450 ml
1 cup	250 ml

0. Sanitize Your Workspace.

1. Fill 16 oz wide mouth mason jars with 1 cup of bird seed for each 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 jar opening 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 syringe into the jar of grain spawn by carefully piercing the aluminum foil straight down along the inside 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 after inoculation 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.

Once the grain in the jar is covered with mycelium give it one more week before moving the cakes to fruiting chambers.

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 by opening a fully colonized grain spawn jar and misting the mycelium cake with water daily.

However, exposing more surface area give the mushrooms more room to sprout.

Fruiting Chambers

• 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. Open and invert a fully colonized grain spawn jar and firmly but gently tap the mycelium cake out.

   • If the cake breaks up that is OK, place the pieces back together when they are rolled in coir.

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

2. Soak to hydrate the coconut coir brick by following the packaging instructions, about 15 to 30 minutes.

3. Layer the bottom of the tub with 5 cm or more of coconut coir.

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

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

Daily

Try to maintain 90% humidity within the fruiting chamber.

0. With a spray bottle of water, 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 on the tub slightly ajar and rest for 1 hour.

2. Place a personal fan nearby to blow upwards 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

• agar

• light malt extract

• light corn syrup

• diammonium phosphate with urea

• 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