I used to sterilize in bulk and pour into petri dishes for many years, but I became tired of purchasing sleeves of plastic pre-sterilized petri dishes that could only be used once. They do make glass petri's that can be used more than once, but since I had so many jars, I never wanted to spend the money on them. And since I am just a hobbyist, I don't need 20 plates for my grows. That being said, my style and recipes are geared for smaller grows and allows me to make just enough agar for the size of my grows. My recipes make about 6-8 4 oz jelly jars of agar.
I mix up my dry ingredients and add to jars of water, stir then sterilize. This is easier and cleaner IMO, due to the fact that you do not need the added step of pouring. Note: I use food grade agar agar purchased from health food stores so the amount in the following recipes may need to be tweaked if using commercial grade agar agar. But a general rule is 20 grams of agar agar for 1 liter of water.
Recipe 1 PDA (powdered):
5 grams (2 tablespoon+ 1 teaspoon) of agar agar
5 grams (1 tablespoon+ 1 teaspoon) of instant potatoes
2 grams (1 teaspoon) of dextrose sugar (also known as corn sugar and can be found at a brewery store). You can also use 1/4 teaspoon of honey or karo distributed as evenly as possible into each jar, but make sure the water is piping hot. This will allow the honey or syrup to dissolve properly.
Recipe 2 PDA (potato water):
Cut up approximately 300 grams (3 small potatoes or 1 large baking potato) of potatoes and place in a pot with 4 cups of water and boil lightly for 45 minutes. Then take out the potatoes and eat or throw away. Finally, pour into a jar or something similar to use as your water. This can be frozen and taken out later for making more plates:
The same recipe as above can be used.
Recipe 3 MEA:
5 grams (1 teaspoon) of light malt extract (also can be found at a brewery store)
4 grams (a heaping teaspoon) of agar agar.
Recipe 4 Cornmeal Agar:
5 grams (1 and 1/4 teaspoon) of corn meal (yellow or white)
4 grams (a heaping teaspoon) of agar agar
Optional: 1 gram of dextrose or 1/8 teaspoon of honey or karo
Recipe 5 BRF Agar:
5 grams (1 + 1/2 teaspoon) of BRF ground fresh (preferred) or packaged flour
5 grams (2 tablespoon+ 1 teaspoon) agar agar
Optional: 2 grams of dextrose or 1/4 teaspoon of honey or karo
I mix all dry ingredients, add 15 ccs of water, add a heaping teaspoon of agar mix for each jar. I then stir and sterilize at 15 pci for 30 minutes. I personally do not use holes or micro tape on my jars, but a lot of growers like using either/or. So use whatever you feel comfortable with.
Once sterilized, I take all jars out of the PC and place them in a sterile tub or similar and allow to cool and solidify. If condensation becomes an issue, wait about 2-4 hours and invert the jars and allow them to continue to cool until you inoculate. Upon opening the jar for inoculation, remove the lid upside down and with a quick motion, shake off all condensation from the lid onto the surface of whatever you using, before returning the jars up right. Then you should be able to inoculate/streak the plate normally.
Any recipe will work for long term storage in slants. I fill my tubes about 1/2-3/4 full of water, add a teaspoon of dry agar mix using a paper funnel, shake very well, wrap in foil, and sterilize at the above psi and time. After it is done, it is important to get it out of the PC before it solidifies. You want to get it solidified on an angle. I use a computer stand for my angle, but you can use a block of wood or something similar. My advice would be to pour the above amount of water in one and test different angles to give you the right thing to use. And of course, you want the slants to cool and solidify in as sterile of an environment as possible.
Edited by peacefrog, 31 October 2015 - 01:40 PM.