Originally Posted by Paulielow
I choose s.04 accidently and the LHBS said I would work fine so I just went with it,
It wasn't till I got home home(30km away) that I realised that I had grabbed a different
Yeast. The room its in now sits at about 21 degrees ambient and the brews at about
24 degrees, so should I try to cool it down or will it be ok
You've probably got more brewing experience than I, up to my sixth batch now starting beginning September, but here's what I'm understanding from advice and threads I've read. The S-04 will handle fermentation temperatures from between 19-25*C. The wort, whilst in the attenuation phase, is generally going to be a couple to a few degrees above ambient temp. If you can keep the wort down close to 19-21*C for the first few days after pitching you'll get less chance of forming some of the off flavours caused by higher fermenting temps.
My first batch was done in the beginning of September and the temperatures were soaring, hitting 35*C in the daytimes. Even though I was using a swamp cooler the fermometer was sometimes up around 26-28 degrees. So, first few days I really blew it on fermentation temp BUT at least it was pretty constant, I wasn't getting huge, extreme, swings in temp, that might possibly stress the yeast. Tasted my first bottle from that batch back on Sunday and it wasn't too bad really, considering. It'd been warm conditioning for two weeks and I just pulled it straight from the box without chilling in the fridge at all.
Anyway, if you're not already using some method, such as a swamp cooler and rotating bottles of ice, to keep fermentation/wort temp down at the lower numbers of the yeast's range, that'd definitely be a good place to start for getting consistency, quality and better flavours in your brewing.
Having said this, when the wort is more in the conditioning phase (after the really active initial fermentation frenzy, high krauzen) , a slightly higher temp might help the yeast do their "clean-up".
With the most recent batch have managed to keep fermometer showing somewhere between 18 to 21*C since, last Sunday, the beginning of fermentation. Probably try to keep there for about another 10 days then let it get up to about 23*C over the next week or two.