I'm posting this because I often see new brewers posting on the forums about foul smells coming from their fermenters. Obviously, when you're hoping that the beer you made is going to taste like the nectar of the Gods, smelling rotten eggs coming from the airlock can be bothersome to say the least. But if you're following good brewing practice; having good sanitation, pitching enough healthy yeast and following a good recipe, the first thing you should do if your fermenter stinks is to RDW and HAHB.
Case in point: On Monday evening my neighbor and I put together an extract pale ale kit. We did everything as I normally do, in fact, I probably paid extra attention to detail because I'm teaching my neighbor to home brew. I rehydrated s-04, pitched at ~63 degrees and threw the fermenter in the swamp cooler. It's been happily gurgling away at ~64 degrees since late Monday night/early Tues. morning.
Fast forward to this morning. I come downstairs and the first thing I smell is what I think is dog $hit. We have a 13 year old pooch who's getting a bit "old", so things like that happen here and there. I woke the happily snoozing dog up and put the poor guy outside before coming in to find the mess. Nothing. He must've had gas.......
Nope, after continuing to smell rotten eggs, I finally had a lightbulb moment. Fermenter. Like I love to do when I'm alone, I went to sniff the airlock. GAG!!! Like I threw up in my mouth a little.
I've used s-04 many, many times. I've been fermenting it (and most English yeasts) at 64-65 degrees most every time I use it and I usually get wonderful, fruity and bread-y aromas coming from the airlock. Not today, today I have a rhinoceros with a bad case of gas living in my swamp cooler.
Poor dog, too bad the ol' guy doesn't like beer.
The moral of my story; fermentation can be downright rank smelling. Even if you're familiar with a yeast, or that yeast is known to be clean, it can flat out reek during fermentation. Don't sweat it. If you know you've done everything right, that stink should be a thing of beauty, because it means that the yeast are doing their job.