I just pitched two 11.5 gram packets (dry sprinkle) onto 5 gallons of 1.095 wort (specialty stout) after aerating (first time using a aquarium pump and stone that I boiled and then soaked in starsan solution). I’m literally amazed… the airlock has started working after only one hour. :o ;D
I know S04 is fast but it has to have something to do with the aeration, I’ve never seen it start this fast.
S-04 is fast. Expect it to chew through that 1.095 Stout in 3-4 days tops, at least the bulk of the fermentation. Watch the temps too. That much/fast of a fermentation will create some heat! Let it sit for at least 3 weeks to clean up. You’ll be amazed by how the yeast packs. The high sedimentation is one of its strong points.
Update: A quote for their web site:
A well-known, commercial English ale yeast, selected for its fast fermentation character and its ability to form a very compact sediment at the end of the fermentation, helping to improve beer clarity. This yeast is recommended for the production of a large range of ale beers and is specially well adapted to cask-conditioned ales and fermentation in cylindro-conical tanks. Sedimentation: high. Final gravity: medium.
S-04 is my go to yeast for stouts. It’s good, it’s easy, it’s fast, it’s an incredible floculator, it’s cheap!
Some have mentioned an undesirable “bready” character . . I’ve not noticed . . or maybe it just compliments the style. Regardless, I like it.
What was your previous aeration technique?
I’ve always just let the cooled wort flow as fast as it could, splashing as much as possible into the fermenter, sometimes I used to shake the fermenter after (when using a bucket).
Its definitely giving up some gas, not a whole lot but still I’m surprised that it is at all. The airlock wobbles about once every couple of minutes. I’m supposing it will start rocking pretty decent sometime in the early morning. I guess time will tell. I hope it finishes as good or better than the wort tasted… I’ve always thought the wort never tasted nearly as good as the beer but this time the wort is more than I expected tastewise. 8)
Just a thought but you might want to trade the airlock for a hose. Just talkin’ from experience… 
Move that fermenter to a cool place (low to mid 50s IMO) ASAP! If you haven’t already, that is.
And +1 to the blowoff hose
**HA! I Laugh in the face of danger!.. ** :
Really though I AM prepared and plan to keep a vigilant eye on this one. 
The wort is 61*F and its only 5 gallons in a wine carboy… and I’ve got some fermcap if it looks like its gonna rock and roll anytime soon. I haven’t tried the fermcap yet and I’m kinda leary on it. A friend (great welder) doesn’t like anything “un-natural” in anything he consumes so I’m trying not to use it… I’m kinda hoping for a favor down the road.
I don’t use an airlock or a hose until the fermentation settles down. Just a loose piece of foil. I don’t even snap the lid down for a bucket. That usually keeps the foam in check (from lack of backpressure maybe.?).
+++1 on the blowoff tube! Unless you like black colored walls and ceiling. Speaking from experience…
I’ve got a nice cake of krauzen on top and there is plenty of head space in the carboy but I’ve got a blow off hose ready if it looks like I’m going to need it.
Pretty fast start for not rehydrating, and pitching into that heavy of a wort. I like S04, I use it in my common bitter. I got the limited edition 1026 (I think thats it) and used it for awhile but it really wasn’t much different than S04, and dry yeast is just so easy to use.