How To Make Agar Plates.
This is what we are going to be making:
Why Make Agar Plates?
The benefits of using agar are numerous. To name a few:
- You can conserve mushroom strands for later use.
- For growing mushrooms you get the benefit of seeing whether you have any contamination before innoculating your substrate. Even if there is some contamination going on you can cut out the healthy mycelium and discard the rest.
- You can also use a wedge of agar from one petri dish to propagate further agar plates.
I hope this is enough to convince you that it is well worth doing!
Time To Make Some Agar Plates
To make 20 agar plates you are going to need:
- a pressure cooker that can reach 15 psi
- an Erlenmeyer flask or glass bottle that can hold at least 750ml of liquid.
- 23 grams of your Malt Extract Agar (MEA) mix – You can get this here.
- Sterile Petri dishes – You can get these here.
- Parafilm – You can get this here.
- 500 ml of Water.
- Latex gloves
- Disinfectant solution or alcohol wipes
- Clean working area – Still air box (you can learn how to make one of those here) or flow hood
As the sterile petri dishes come in packs of 20 it is worth making up the whole lot at once as once the bag of sterile dishes has been opened, it will be hard to keep them sterile. You can always wrap them up with the parafilm and store them for later use if you are not able to use them straight away.
To make 20 agar plates you are going to need about 23 grams of your MEA mix. Weigh this out on your scales and mix with the 500ml of water in your flask or bottle. You can cover the top and give it a good shake. Then cover the top with some tinfoil so that no condensation can get into your mix while it is being sterilised like so:
Once your agar mix has cooled down enough to comfortably pour, start pouring in a quick and efficient manner, keeping the amount of time the inside of the petri dishes are exposed to the air to a minimum. Work your way from the bottom of each stack, lifting up from the lid of the first petri dish, pouring, lowering the stack back down and lifting up from the lid of the second petri dish, until you have worked your way up the stack to the top. Do this until you have used all your petri dishes.
Once all the plates have been poured leave them to fully cool before going on to use them or parafilming them up for later use. They can be stored for up to 1 month. You can learn how to use parafilm here.
And that is pretty much it.