So I've got a classic american pilsner that's been sitting for about 84 hours now with no signs of fermenting. No bubbles in the air lock, no krausen. It was aerated with an aeration stone, and I cold pitched (50 degrees) two packs of wyeast pilsen lager yeast. This morning I took a hydro reading. The reading said I had dropped .002. So I guess it has done something, but a lot less than I would hope after almost 4 days. This morning I gave it another 30 minutes of aeration and am warming it up from 50 to 60ish. If I don't see anything more happen soon I think I'm going to pitch a packet of S-05. This was a really awesome all-grain wort that I spent a lot of time on and I'd rather turn it into an ale than have it spoil by sitting around for a few more days.
My worry is that whatever remaining lager yeast there is will make some funky flavors at the ale temperature. Should I attempt to kill them off with some campden tablets before warming up and pitching the ale yeast?
Thanks for your ideas.