What is the appropriate consistency? Well that's down to test and error. Yet I would certainly state that on getting in the water, you want the mash to begin breaking up instantly. If you are angling in much faster water or it's ice-cold, after that you can make it merely a little stiffer, so that it begins to damage down nearer all-time low, which is where the chub are likely to really want to feed in severe sub-zero disorders.
My personal inclination is to then fish a piece of bread crust in between 1-4 inches off the bottom. Used combined with a feeder or simply some try on the line, crust is a deadly chub lure. With a few adjustments to bait as well as hook dimension, it can after that be relied on for roach or even barbel. Try this winter season.