Faster than sound fermentation

[yourlastchance89]

Background :

So this past weekend I brewed a smoked porter. For reference it is the recipe in Brewing Classic Styles. OG called for 1.065. I do BIAB and managed to achieve a 1.073. The recipe calls for 2.5 liquid packets(which I equate to 250 billion cells), but I made a starter using Thames Valley yeast using a stir plate, and adding enough DME for 300 billion count when finished. I do not oxygenate. I aerate by stirring and whirlpooling with this bad boy
https://youtu.be/TmMpEkOHboo
(not the exact paddle but same line of products). I do that periodically as it cools to pitching temps, which from boiling takes about 45ish minutes to get to 64° F. As this goes on I decant my starter and put it back on the stir plate to losen up the yeast at the bottom of the flask. I then dump the entire contents of the wort in the fermenter(absolutely everything) and pitch. This time my blow off tube started to bubble in about 2-3 hours and I let it climb to 66°F and have held it steady. Is this bubbling indicative of the beginning of fermentation? If it is, is there anything wrong with it taking off so fast? Could it possibly result from overpitching? And what percentage over an intended yeast population count actually counts as overpitching?(I see numbers for underpitching all the time never overpitching)

 

[plazola86]

This isn't uncommon. The lag phase your talking about is just the yeast reproducing to start fermentation. Since you pitched a big enough starter, fermentation started almost immediately since there was no need to reproduce.

 

[SlitheryDee]

It's just a low lag time. I seem to see similar lag times when I pitch slurry, and yeast from a starter should be more active than that. I brewed a cream ale yesterday, pitch from a jar of warmed up slurry at about 3:30 P.M., and a krausen had already formed by nightfall some 5 hours later. That one was dangerously close to the top of the fermenter, so I'm holding the temp at 62F to hopefully keep the krausen tame.

You might have overpitched by a little, and that probably is part of the reason you're seeing such a short lag time, but I wouldn't worry about it. You don't see as much about overpitching simply because it's just not as big of a concern. You'd have to overpitch by a truly gross amount to have it negatively impact your beer IMO.