Preparing Agar – Growth Medium for Bacteria

To demonstrate that this experiment can be done at home, we prepared agar ourselves. We followed the advice from the Institute of Molecular Biology, Slovak Academy of Sciences, and the instructions provided here.

What We Needed:

240 ml distilled water
7 g agar powder (we bought it here)
8 g sugar (we used powdered sugar; pure glucose would be better)
1 cube beef bouillon
Petri dishes or containers to pour the prepared agar into
A cooking pot
A measuring cup

Step 1

First, we sterilized all the tools. We set the oven to 170°C and placed all the tools inside. We left them there for 3 hours. We also sterilized soil from a pot by wrapping it in aluminum foil.

Step 2

In the measuring cup, we mixed:

1 cube of bouillon
8 g of sugar
240 ml of distilled water
7 g of gelatin (agar)

Step 3

We heated this mixture and let it boil for 1 minute.

Step 4

e allowed the agar to cool to 49°C and poured the mixture into the Petri dishes (containers).

Step 5

We closed the Petri dishes (containers) and, after they cooled, stored them in the refrigerator so we could later draw on them in the glove box. The dishes should be stored with the agar side up to prevent condensation from dripping onto the agar.

Page updated

Google Sites

Report abuse