I tell people that are interested that's it's not hard so long as you follow the 3 cardinal rules. Watch your temp, humidity and airflow. Yes, being sterile is important, but only until the substrate has been totally seeded. By the time you take the cakes out of the jar to give them a water bath they are fairly resilient. The fungus has it's own immune system. Granted, you still can't be exceptionally dirty, you just don't need to be extra sterile.