Originally Posted by 77bawls
I want to reuse the yeast from them for the other flavors. I wanted to just add the new stuff on the trub (forget what it's called for mead). Do I need to worry about getting the krausen out of the jug?
It is called lees. And in batches where you have fruit pulp, what forms in the bottom is referred to as gross lees. The problem with just adding more must on top of gross lees is that the gross less may develop sulfur odors. That doesn't happen in every case, but it certainly can, and that can ruin a batch. If you take some of those lees and aerate them well and pitch them in the next batch that may reduce the problems with sulfur.
In a batch made with apple juice, there won't be a lot of fruit particles in the lees and it may be OK. However, apple batches frequently produce sulfur odors and if these batches are stinky at the end of fermentation, you may not want to pour more must onto stinky lees - at least not when a fresh packet of yeast costs all of $1.