OK here it is i have a pale ale in a 5 gal carboy started at 1042 and finished at 1010, i also have a DIPA in a 6 gal carboy og 1076 fg 1010. I'll be brewing an RIS within next week or and i want to ferment it on the yeast cake of one of the two. The problem is, im going to need more space than 5 gal will allow me, and i fear the other cake is not reusable because it was feremented so high. So is it safe to dump the yeast cake from the 5 gal (pale ale) to a new clean and sanitized 6 gal carboy then lay the RIS on top of that? Or should i just buy some new yeast? *note i have no intention of harvesting/washing yeast
safale 04, i thought so too, but ive never transfered yeast, dont know what the infection rate would be.
I don't think infection is as much of an issue as the yeast quality to beer style. From what I've read (I always just buy new yeast since I'm doing small batches it saves me time) the yeast will start to become comfortable which ever beer you pitched it last and acclimate to it's surrounding. Such as if you brewed a big DIPA then tried to pitch it to a blond you might have some issues, especially if you leave some trub. My yeast knowledge is fairly spotty but that's how I understand it. I wouldn't worry if I were you though.
Sanitize the mouth of the old carboy and whatever transfer equipment (funnel?) you'll be using. The probablity of infection will be about the same as if you pitched from a vial or starter flask, i.e. very close to 0.
