I plan to brew a big barleywine in the upcoming weeks and would like to use the 2nd runnings for a mild with the idea of using the mild as my yeast starter for the barleywine. Currently, I'm thinking of letting the mild go for ~72 hours before pulling off of the yeast to spund in a keg and racking the barleywine wort onto the mild's yeast cake. In those 72ish hours I'd keep the barleywine wort in a CLEAN and sanitized carboy, or maybe a keg. I've never done anything like this, but I know there are some that have waited up to 48 hours with good results. I feel pretty confident about my current sanitation process, but of course everything can always be improved on and in this case I'd probably do an extra step to keep my nerves at bay. So aside from potential contamination from poor sanitation, am I really risking much here? Has anyone else waited this long to pitch into wort? Would I be better off just making a separate, giant starter for the barleywine and pitching both beers on brewday as I normally would?
Yes. Early in my brew-life some liquid yeast I pitched never started in the primary (only time I never made a starter, grrr). It took two days of worrying, plus another two days to get new yeast shipped (only time I never had "spare" yeast on hand, grrr again) before the wort had yeast that was actually alive. It worked out okay. IMO, absolutely yes . . . worth it for peace of mind.