Or is it both? I was reading up on esters and I came across two different threads, one stating that 05 gives of peach esters at lower (50-60) temps and the other stating that it was higher (70-75 I think) temps.
From what I understand it (supposedly) gives off a subtle peach ester at temps under 60 and can throw all sorts of spicy/fruity esters above 72 or so. I've fermented it low and don't think I got peach, but I wasn't looking for it. Currently fermenting a rye IPA at around 60 and will be interested to see if I pick up on it this time.
Last winter I had to leave town for a week and came home to a 57 degree fermenter. I don't generally need a heater here! I just immediately cold crashed since it was done, I didn't think to check if it had soiled itself.
There was definitely peach, and a hint of diacetyl. I think the diacetyl is quite uncommon for US-05, but I have definitely heard about the peach. I didn't like it.
It is a sin in my brewery to let ANY non Belgian get above 66, so I can't comment on the high side.
I don't have a huge amount of experience, but, I've used US-05 more than anything else. I've found it to be nice and clean in the 62-66 range, but if you're not careful, it'll get good and hefeweisen-esque on the warm side.
Can't say exactly where "the warm side" cuts in, as it was pretty much a question of "why the hell does my IPA taste like a hoppy hefe ... oh, huh, there's this thing called temperature control, maybe I should do that," but you'll get some nice banana and clove if you just let 'er ride.
I have used 05 many times and for me, I would get the peach from it when fermenting in the low 60s. It wasn't necessarily a bad flavor, but it did seem to take over the beer. I find 05 to be at its cleanest between 66-70 (beer temp, not ambient).
What I thought was strong peach smell, a somolier who tried it said she got lychee on the nose. So who knows. I think the citra excentuated the aroma. I wouldnt be upset if all my IPA's smelled like peaches
I've used 05 at 66-70 F with no peach esters. Like others, I've read other's threads who've gotten the peach at lower temps. For what its worth, though, I've about stopped using 05 in favor of BRY-97. No off flavors at all and seems to ferment cleaner and crisper than the 05.
I've fermented S-05 at temps between 63 and 69, and never got any peach. Did taste an APA brewed by a fellow homebrewer that was fermented at 60° that had some peach flavor to it. I've split batches and compared S-05, WLP-001, and 1056 all fermented at 65°, and did double blind taste tests with a group of beer snob friends. Nobody could tell the difference, and people who thought they could weren't able to choose the same beer twice in a row.