I just watched the video of RoadKill about grain to grain transfer and I learned that you need to be very sterile when you transfer the colonized rye grain to the non-colonized grain. But then I started to watch Lets do straw and he just open the jar and empty it in the straw without anything sterile. (makes sens since the mycelium should be  strong enough to defend itself. So then why is it important to be sterile when transfering rye grain to another jar?!?!!?!?! :?