Growing materials at home: Hard Mycelium Materials Manual


#1

We wrote this manual to share our knowledge on mushroom materials and it is based on our experience and own experiments. We hope you build on this knowledge and share it as well. The manual is to be used under a Creative Commons license, as detailed below.

Use of this document. If you have questions about the use of this manual you can address them to: winnie@glimps.bio. You can also add comments and questions to the document online, so others can share in the insights. This manual is a work-in-progress and can be adjusted.

License. Fungi Materials Manual by Magma Nova is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

Creative Commons License

Content

1. Introduction

2. Equipment and ingredients

3. Step by step

4. References


1. Introduction

Climate change, waste and the resulting pollution are among the biggest challenges of our time. This realisation motivated us to start experimenting with sustainable and biodegradable materials. We focus on materials that are directly grown by micro organisms.

Mushroom materials are one of the materials we work with. They offer tremendous potential as a building material in manufacturing of furniture, architecture and packaging. The material consist of fibres that are glued together by the roots (called mycelium) of a fungus.
Below we have made a simple guide to making your own material at home or in a local DIY biolab (see www.diybio.org).

The following manual describes general instructions and the practical steps you need to take to make an object. Start from step 13 if you took home a fungus growing in a mold. Read all the steps before you begin, to prepare for them. You cannot pause for very
long once you’ve started as this would compromise the sterility and thus the outcome of the experiment.

1.1. Summary description of the process

There are five phases for growing an object made from mushroom material. First, we need to prepare everything we will use. This means sterilising or pasteurising all the tools and resources. After that, we will make the mixture in which the mycelium will grow, the substrate, and put it in a mold. Third, the mycelium will grow in the mold for about 10 days, depending on several conditions. Next, there is a second growing phase outside of the mold. Lastly, we will harvest the object and dry it.

1.2. Sterility

First off, it is important to note that you need to work as hygienic as possible. This means you must disinfect everything the material will touch. You can disinfect things with rubbing alcohol (70%) or other products sold for this cause, like disinfecting wipes. To sterilise them, rub the bowls and spoons etc. you use with alcohol, as well as the table you work on. Wear gloves and rub the gloves with alcohol. Whenever you touch a non-disinfected surface, you must disinfect your hands again. Sterilise your hands before every ‘action’ you do.

Try not to lean above the materials with your hands or face, so that particles like dust can’t drop on your experiment.

2. Equipment and ingredients

Depending on your location, you might or might not have access to this. Usually, you will find all the necessary hardware in a DIY biolab.

  • Mold of your choice. You will need a foil to cover it if you don’t have a lid. The mold has to be metal or plastic, else you will need to cover the inside with plastic foil (eg. a wooden mold)
  • Mixing bowl
  • Coffee grounds (It’s actually better to skip coffee grounds unless you work 100% sterile as it increases chance of contamination)
  • Woody substrate (hemp, saw dust, fine straw…), enough to fill your mold
  • Cooking pot
  • High pressure cooker (or better, an autoclave)
  • A vertical gas fire, like a camping fire (or better, a bunsen burner)
  • Cloth bag (like a white pillow case)
  • Mushroom spawn (seeds), buy at local supplier or at www.mycelia.be
  • Stove
  • Water
  • Plastic gloves
  • Alcohol (70%) or other disinfecting product
  • Thermometer
  • New, fresh plastic bag

3. Step by step

3.1. Preparation

Sterilising and pasteurising the materials and resources. For simplicity, we will be using hemp fibres throughout this manual. The recipe is the same if you switch it with sawdust, fine straw or other woody substrates.

Step 1: Mix hemp fibres with coffee grounds (Leave out coffee grounds if you’re working at home or anywhere not in a lab) in a bowl. The amount of coffee you will need is about 1/10th of the volume of your bag. This does not need to be precise.

Step 2: Fill a cloth bag with the substrate (mixture of hemp and coffee), put it in the cooking pot and fill it with water. The hemp needs to be fully submerged, so don’t use too much hemp. The hemp will absorb some of the water, so make sure it stays submerged.

Step 3: Put the cooking pot on the stove and bring it to a boil. This can take a while due to the large amount of water to be heated. Let it boil for 30 minutes.

Note: if you’re using a pressure cooker or autoclave, you should soak the fibers in water first (ideally overnight, but you can get away with 30-60 min). Then, place the fibers in a heat resistant bag inside the autoclave or pressure cooker and operate them as long as needed (usually 20 min at 121°C.)

Step 4: After 30 minutes, remove the cooking pot from the stove and pour away the water. If it’s still too hot, let it cool as soon as possible. From this point onward, the substrate is pasteurised. In other words: most micro-organisms are dead, except for the most temperature resistant ones. This means that you should keep the substrate closed off from the air as much as possible (keep the lid closed) and avoid contact with surfaces (hands, utensils, …) that are not disinfected.

Step 5: The substrate will cool off faster if you remove it from the cloth bag. Try to remove the bag without exposing the substrate to the air too much and do it calmly, but fast. Close the lid and let them hemp sit in the cooking pot to cool off.

Step 6: The next steps will need to be done in rapid succession to avoid unnecessary risk of contamination. If you need to place foil in your mold or need to put certain materials within reach, now is the time. Read the steps before you start.

3.2. Making the mixture

Be more aware of disinfecting hands and materials whenever you use them from now on. Don’t leave lids open unnecessarily, to avoid contamination. See pictures below.

Step 7: Working sterile: put on your gloves and disinfect them whenever you touch the substrate or mycelium mixture. Anything you use from now on has to be disinfected. When something disinfected touches something that is not disinfected, you must disinfect it again. Anything you do from now on where a lid is off or when something that was previously sterilised or pasteurised is in contact with the air, you should do in the vicinity of a vertical flame. The reason for this is that the flame creates an upward air flow which prevents organisms from falling into your experiment. Ignite the flame 5-10 minutes before you proceed, to allow for a steady airflow to form.

Step 8: When the substrate have cooled down until about 30-35 °C, we can prepare the mixture. Disinfect the thermometer if you will directly touch the substrate to measure the temperature! Disinfect your mixing bowl and place it in the vicinity of the flame.

Step 9: Prepare the mold in the vicinity of the flame. Cover the inside of the mold with foil, this helps a lot with removing the object from the mold later on. Disinfect the mold and foil and make sure you have everything you need, sterilised, within your reach, including some foil to put on top or the lid if your mold has one. Every inside surface of the mold has to be disinfected. From now on until step 12, you must keep going without pause, because of the exposure to bacteria and fungi in the air.

Step 10: Place enough substrate to fill your mold in the mixing bowl. Add mushroom spawn at 10% of the wet-weight. Mix everything well and make sure to break the mushroom spawn chunks into little bits. The more homogenous the mixture, the better. Don’t take too long, because the risk of contamination rises the longer you are mixing.

Step 11: Put the mixture in your mold. You might consider to add sterilised plastic foil in the mold before, in order to easily un-mold, because the mycelium can sometimes stick to the mold. Press it gently, but not too much. If the mixture is packed too tightly, the mycelium can choke and die. It can also produce too much heat and effectively cook itself.

Step 12: Cover the mold with plastic foil or lid (sterilised!). This ensures no dirt or unwanted guests get inside the mold and it helps to prevent evaporation of water. If too much water is allowed to escape, the substrate will dry out. Use painters’ tape to shut off any holes in between the foil and the mold, to prevent insects from getting in.

3.3. First growth phase: in the mold

Step 13: Place the mold in a dark environment at 20-30 °C. The ideal temperature is about 27°C, but if you feel you have made some mistakes working sterile, a lower temperature might be more suitable. The mycelium will still thrive at 20 °C (although it will take a little longer) and contaminants will be slowed down in their growth. The mycelium is very receptive to his surroundings. In your home that circumstances are different, so it is also normal to allow some time to the mycelium to adapt to his new habitat. Therefore, don’t move your object too often, and make sure the growing conditions remain as constant as possible.

Step 14: This growth stage will take anywhere between 5 and 14 days depending on a long list of conditions. Light, temperature, amount of spawn, species, type of substrate, nutrient additives and moisture all have an impact on the growth stage. There is no clear end of this stage. If you can see mostly white, with no more brown spots (or whatever colour your substrate was at the start) it’s likely time to remove your object from the mold. The mycelium will have formed a nice white layer of fluff. If there are brown or yellow spots or wet spots on your white layer, you have waited for too long. If there are not too many, nothing is lost though, just proceed to the next step.

3.4. Second growth phase: outside of mold

Step 15: There is no need to work sterile at this point. Washing your hands is enough.

Step 16: Open the mold and carefully remove the object. The object is probably still quite fragile (that is the point of the second growth phase). All the water makes it heavier and unable to support its own weight. If you covered the inside of your mold with foil, you should be fine. Get a new, clean plastic bag and place the object in it. Close the bag.

Step 17: Let the object grow under the same conditions you used during the first growth phase. This will take another 5-7 days.

Step 16-17: This cast of a face shows the difference before (left) and after (right) the second growth phase

3.5. Harvest and drying

Step 18: After about a week or when you see the object is completely white, you can open the bag. The object will still be fragile, but a little less than when you first opened it. Be careful and support it with your hands.

Step 19: Put the object on a grill or a plate and put it in the oven at 60-80 °C. Depending on the thickness of your object, this can take 2 hours to a long time. Turn the object around every hour or so to allow water to evaporate from every side. If you cannot dry it in one run, you can leave the object sitting in a cold oven for a day or so. Just make sure there is a way for humidity to escape, or other organisms will start growing on your object.

Step 20: Some objects that are quite thin, can just be dried in the open air at room temperature or close to the central heating.

Step 21: There are a few ways to check if your object is completely dry. The surface cannot be springy, but must be rigid. The air in the oven or around the object must be dry, not humid. The smell will change from foresty, food-like to musty when you heat the object. When the object is cooled down, all smell should disappear.

Step 22: Congratulations, you have your very own biodegradable mushroom material object!

Share your results here below :slight_smile:

4. References

Manual made by:

  • Elise Elsacker (researcher)
  • Kristel Peters (shoe designer)
  • Winnie Poncelet (bio-engineer)

Websites:

Facebook:


#2

this is simply wonderful. a new person at Hackuarium has just begun some mycelium, and we are hoping his recently built ‘rack’ and our old hood will be sufficient for growth and sterility. I will share this with him as extra inspiration!!
best,
Rachel


#3

we actually autoclaved a big bag of left-over malt from beer making to use as a substrate/nutrient source, and the starter mycelia are growing already. do you think the malt is a good idea?? (Hi, Elise and Winnie!)


#4

It’s definitely a good idea to use malt :slight_smile: let us know how that went.
I’m trying to put our manual in wiki format here. A nicer version with pictures is here: https://docs.google.com/document/d/1uRifizJav72kHglFgek2zZZUOKyDP63I4idw2--VEdY/edit

The forum here is new, so will add the pictures etc. here soon :slight_smile: Also expect more guides and manuals from others who join the forum.


#5

Our following two manual pages will help you doing that:

To get the formattings across automatically, I propose you export from Google Docs as a HTML page, copy the HTML source code into a web-based HTML-to-Markdown conversion service, and copy the Markdown into your post above. Some manual polishing will be needed, but I it saves a lot of manual work for sure.


#6

What is the reasoning behind the oven temperature of 60-80°C to dry objects in step 19? This is in general a good base temperature to “kill” the mycelium and thus stop growth?

Does the drying temperature affect the rigidity of dried mycelium?


#7

It’s a temperature that is not too high, because otherwise it might burn in the oven. Also then the object does not become so brown like it’s been baked. It is enough to kill the mycelium and also to dry it out.

The drying process can definitely affect the rigidity, but I have not found correlations. It can sometimes crack, but I don’t know what are the underlying causes.


#8

Elastic moduli of live samples are smaller compared to the dried samples. So, yes, drier samples are stiffer.

When completely dried the filaments are not supported anymore by the internal hydrostatic pressure and for this reason the hyphae is more flatten and that might affect the rigidity of the material.


#9

#10

it’s 10% of the weight. Will not make so many difference but weight is easier to measure :wink:
Can I change the post?


#11

And maybe indicate that for complicated moulds it is better to put a plastic foil in it before, for an easier unmoulding.


#12

Thanks for asking, but since it’s a wiki, feel free to improve it at your own discretion :slight_smile: Good remarks!


#13

Hey there,

I wanted to share the size reduction after drying phase.
According to my observations:
5.5% less of its original size with oven
3.7% less by drying naturally


#14

That’s less than I thought! Thanks for the input.

Is there anyone else who has estimates for shrinkage? Ping some growers @Elise @BabetteHendryckx @Leen @barbaradb @MalteLarsen


#15

@LumiFungi @winnieponcelet
It depends on the type of fibres, the fibre size and direction. We have shrinkage ranging from 0.2 to 9 (or more).
I have no conclusions to make yet on exact %, because by changing the preparation method it also seemed to reduce the shrinkage.


#16

Thanks very much for the guide!

In the equipments section, you wrote:

but I don’t see it in the protocol, is it necessary? or cooking pot is enough?


#17

Thanks for your feedback @Francois

You make a good point. A cooking pot is enough for pasteurization. High pressure cooker or autoclave are for sterilization.

I edited the text to make it clearer. Works like that? :slight_smile:


#18

Here is a standard protocol that I’ve developed for the production of mycelium-materials:

https://www.dropbox.com/s/n2lhhav44g64nr4/Protocols%20-%20%20Standard%20protocol%20for%20mycelium-material%20samples.pdf?dl=0


#19

thanks


#20

Hi all, thank you for sharing those good tips.

I am wondering which kind of spawn is best to create mycelium materials. Currently I’m doing with pleurotes but what about shiitake and trametes versicolor (and others…)? I guess different types of mycelium can change the final properties of the material.
Maybe there is already a specific discussion about this topic on the forum?