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Sporeworks'
Basic Agar Tek
How
to prepare agar and pour in petri dishes.
by Compiler
There are innumerable formulas for making agar
to grow mushroom mycelium on. Here we will discuss
the basics and let you experiment to develop your
own favorite recipe for your favorite mushroom.
Remember this mixture is designed as a rich food
source for your mycelium to grow on and it will
also support many other organisms. First you must
have a recipe to follow. Let's keep it simple
for our example. Of course ingredients can be
added, deleted, or combined at different ratios.
For many mushrooms malt based agar is sufficient.
| 1.
For this ultra simple example we will use
a 50 - 50 mixture of agar
and malt
extract. |
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| 2.
To fill 20
Petri dishes we will need approximately
500ml of solution. We will need 10 grams of
agar and 10 grams of malt extract mixed with
500ml water. An acceptable container is an
ordinary quart jar with matching plastic
lid and synthetic
filter disc fitted inside the lid. |
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| 3.
After stirring contents, loosely fit the
lid with the filter disc fit inside the lid
and secured on the jar. |
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4.
Place in pressure
cooker and add 3000 ml water to the
pressure cooker (less water should be used
for smaller pressure cookers, achieving
one inch of standing water on the side of
the jar).
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Sterilize
for 30 to 45 minutes at 15 pounds pressure.
NOTE:
Make sure not to exceed this pressure or
time frame or the sugars in the malt will
caramelize thus promoting mutations or cottony
growth, which is not a good thing.
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5.
After cooling and returning to normal pressure
open sterilizer unit in front of a HEPA
filtered air stream or remove jar into a
clean and sterilized glove box.
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6.
As soon as jar is just cool enough to hold
but while the contents are still molten,
pour just enough in to each petri dish to
cover the bottom. Fill all 20 dishes in
the sleeve.
NOTE:
With experience you will be able to do this
filling process quickly. Open dishes for
as short a time as you can and remember
when you open a dish air will 'spill' in
and potentially contaminate your agar before
you even start so be careful.
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7.
Allow filled dishes to cool and
solidify in the air stream. Once the agar
is solid the plates can be stored or used.
Seal dish edges with Parafilm.
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