As Debbie stated, the temperature of the plate matters. We are using PYCa media and pull out plates to warm to room temperature before lab starts, but sometimes students need additional plates. We ask them to let the cold plates warm a bit before using. However, if they are in a rush or impatient and place top agar on the too cold plate (usually with some condensation forming on it), their top agar slides around because a layer of water forms between the cold plate and the hot top agar. When they re-do it with room temperature plates, everything works as expected.
Edited 14 Sep, 2018 06:30