1 A do-it-yourself approach for basic basement steps starts around $250-$350 for materials, and takes about 3-4 hours. 2  That's with standard lumber, such as pine; costs can go much higher with more expensive wood, such as oak.
Pour enough melted agar into each sterile plastic petri dish to cover the bottom - about 1/8 to 1/4 deep. Replace the lid immediately. Place agar plates on a counter top to cool and set. Agar medium will set like stiff gelatin at room temperature. The agar medium is now ready for storage or use.
Cool it by: 1  leaving it in a cool place. 2  taking it out of the original cooking container. 3  using a fan to circulate cool air. 4  cooling foods like rice and pasta by running them under the cold tap. 5  putting the container in cold water. 6  breaking down the food into smaller quantities, which will cool much quicker than large amounts.