We've recently started noticing a bit of a wet, old grain funk coming out in our latest on-grain fermentations. I'm not sure poor sanitation is the issue, but I'm not ruling it out, either. It started when we went up to 2.5 lbs/gallon grain bill. I'm thinking periodic agitation during the 5 day ferment might help make the yeast more mobile and able to out-compete the bad bugs? Does anyone have experience with this issue? Our fermenters are closed to the atmosphere and vent through a blow-off tube.