Adding yeast to fermenting beer

[ImperialStout]

Should I add a second packet of yeast to this beer? Despite the activity, (see photo) am concerned there won't be enough yeast to produce 10% ABV.

Didn't see 2 packets of yeast were required. One fresh packet of dry Nottingham, re-hydrated, produced these results in 12 hours. Fermenting at 70 F. Have changed blow-off bottle twice so far. The plug blew off once due to a plugged tube. Tube in photo is (was) clean.

Making a barleywine that should come in at 10% ABV. SG was 1.070, after boil was 1.104, looking to get FG of 1.030.

Any thoughts?

 

[dcbw]

One packet probably won't do much since there isn't much O2 left and the yeast won't reproduce much. What I would do is make a starter from the new packet and pitch that, since it would have grown a bunch of new yeast already and the yeast will be healthy and active too. They'll be able to help out much more than just one packet alone.

 

[j1n]

Mistake #1, using 1 packet of yeast, Mistake #2, using Notty at 70*.

1 packet re-hydrated, at that gravity, will certainly stress the yeast out and dont be surprised if you have off flavors. Also best to keep Notty under 65*.

 

[ImperialStout]

Thanks,

Not sure if lack of oxygen or fermenting at 70 F is a problem. I inject pure oxygen into cooled wort in the carboy for 90 seconds. Use a .05 micron SS diffuser at low pressure so there are no large surface bubbles.

Nottingham fermentation temp from the Danstar web site is 57° to 70°F. With relatively high alcohol tolerance, Nottingham works well in imperial beers. I usually ferment at 68 F but a LHBS owner just recommended 70.

With so much activity, (the wort in the carboy looks like a snow globe someone just shook up) I am concerned adding a 2nd packet of yeast will over pitch and ruin the beer.

Any other thoughts?