How to Make Agar

Agar Formulas

Malt Extract Agar

  • 30 Grams Agar
  • 20 Grams Light Malt Extract
  • 1000 Milliliters of Water
  •  2 Grams Nutritional Yeast (optional)

Potato Dextrose Agar

  • 25 Grams Agar
  • 20 Grams Dextrose (corn sugar)
  • 5 Grams Dehydrated Potatoes or, 5 Grams Potato Starch
  • 2 Grams Nutritional Yeast (optional)
  • 1000 Milliliters of Water

Coconut Water Agar

  • 20 Grams Agar
  • 15 Grams Glutinous Rice Flour
  • 1000 Milileters Coconut Water

Directions For Use

  1. Put your water in a pot and add your ingredients
  2. Turn heat to medium high
  3. Stir frequently!!!
  4. Bring agar mixture to a boil
  5. Turn off heat

Plastic Petri Dishes Directions

  1. Pour your agar in to a heat resistant container. A flask, beer bottle or bottles, whatever will fit in to your pressure cooker. 
  2. Plug the mouth of the bottle with pollyfill (you can use paper towels in a pinch)
  3. put 2-3 layers of aluminum foil over the top of the bottle
  4. Pressure cook at 15 psi. for 30 minutes
  5. Be sure not to overheat your agar mixture, or you could caramelize the sugars and your mushroom fungus will be stunted

No Pour Method

There are many heat resistant containers that can withstand being pressure cooked, but plastic petri dishes are not one of them. You could use glass or pyrex petri dishes, baby food jars, or you could use any food grade plastic container that is made to heat food in the microwave. Surprisingly, these containers will withstand being pressure cooked. Most plastic containers have a rating symbol on the bottom. It is a triangle with a number in it. If this number in the triangle is 5, then it is heat resistant, also called pp5. If you look around at things, probably in your cupboard or at the store (tupperware,) you will start to notice this pp5 symbol. I myself like to use 8 oz deli dishes. The type you get your macaroni salad in from the local grocery store. You can usually find these at a restaurant supply store or online.

No Pour Directions

  1. Pour 1/8 to 1/4 inch of your still hot, well stirred agar in to each container
  2. pressure cook at 15 psi. for 20-30 minutes
  3. Be sure not to overheat your agar mixture, or you could caramelize the sugars and your mushroom fungus will be stunted
  4. Let pressure cooker cool!!!
How to Inoculate your agar
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