If you are going to shake, this would be the appropriate time to do so.
I personally never shake during colonization. If you shake too hard, you could damage the mycelium to a point where it won't recover.
What I do is PC the jars.... right when it finishes PCing....I open the pc, shake the hell out of the jar and let cool.
When I inoculate, I tip the grain on a 45 deg angle and shoot in spores right down the middle of it, so it hits just about everything in the center. Then I shake the ever loving shit out of it again.
Doing this, I have found that colonization is pretty uniform (covering all sides of the jar) during incubation and I don't need to shake again.
