Originally Posted by iansbrew
Are you guys speaking from experience or stating conventional wisdom?
Try it for yourself. Ferment two identical beers with one at 64 degrees and one close to 80. The difference will be almost shocking side by side.
And I know from experience because I made the same mistake almost all new brewers make and fermented many beers way too warm when starting out. It was still beer and most were drinkable, but they were hardly in the same league as even a mediocre commercial beer. As soon as I had a way to control fermentation temps and keep them below about 66 degrees even the same recipes I made before came out like a completely different beer.
You can have the best equipment in the world and an award winning recipe, but if you can't keep fermentation temps under control none of it matters. It is probably the single most important aspect in making good beer. It's right up there with time and making sure the beer isn't rushed.
At any rate, in the end you'll still make beer, and it will probably be pretty good to boot. But it won't turn out as good as it could if you were able to keep your temps in line.