While fermenting, is there any reason why I shouldn't shake my primary fermenter occasionally? I have a batch right now that seems like the yeasties are lazy. After 3 weeks The gravity went from 1061 og to 1030. So I shook it up, and a day later there was activity in the blow off. A week later blow-off activity had pretty much ceased and the gravity was 1021. Yesterday I shook it again and the blow-off had some activity again. Is there anything wrong with rousing the yeast occasionally? This batch is using white labs 550 which is supposed to provide high attenuation.