Measure the appropriate amount of agar and beef or chicken stock for the amount of Petri dishes needed and add to the beaker. Every 5 Petri dishes require 100 mm of stock and 2 g of agar.
Sterilize the clean glass stir rod with the Bunsen burner flame, and stir the mixture until it melts. Use heat-resistant hand protection and hold the beaker over the Bunsen burner. Boil the mixture for one minute while constantly swishing or stirring the mixture. Allow the substance to stand for two minutes
Pour the agar one-fourth inches deep into the sterile Petri dishes and immediately reapply the lid to avoid contamination. The mixture should cover the bottom of the dish evenly. Allow the agar plates to cool to room temperature. The agar should become a smooth, gelatinous mold when completed.