recently opened a tube of white labs calif ale yeast (wlp001) in order to dump it in a starter. I shook it, not like an animal, but shook well. There was no CO2 pressure release like the other tubes i've opened. in fact there was none at all. I know i need to wait and see if the starter builds up CO2 (bubbles) or any activity, but should i be worried that there didn't seem to be any build up from the tube??