Imperial stout fermentation question

I don't have much experience with big stouts, having done only one last year. I also don't have experience using WLP002 either. I brewed a 3 gal batch of a 1.110 OG imperial stout 7 days ago and pitched WLP002 off of a 1.8L starter calculated from yeastcalculator. As per usual, I used yeast nutrient and aerated with pure oxygen and a diffusion stone. I gave it ~80 seconds at pitching per BrewCipher and 30 additional seconds 13 hours later. I noted how little krausen it had during the first several days, max maybe 3 in, but thought it was probably the yeast. My experience with other yeasts and beers with higher gravities, albeit <1.100, has been a much more aggressive fermentation. Anyway, my curiosity led me to get a quick sample tonight to check on its progress. It read 16.1 Brix for an SG of 1.057 and AA of 45%. The anticipated FG is 1.032. So the question is, does this seem appropriate at this stage only 1 week in for a big stout or for this yeast? Or should this be further along at this point? One way or the other, I'll certainly let it sit for another couple weeks before doing anything.

 

Sorry, forgot the temps. I pitched and had it at 65F the first 3 days. Brought it up to 69F over two days, so it's been there for 3-4 days now.

 

I am using a 5 gal carboy. I wanted plenty of headspace, thinking the fermentation would be very vigorous. I learned my lesson on headspace a few years ago when I did a small 3 gal batch of a hefeweizen in a 3 gal carboy!

 

I usually let any style go for at least 2 weeks before doing anything. Curiousity got to me given the relative lack of krausen and never having used this yeast before. Probably a mistake.

 

So a little update on this beer. I checked the gravity a few days ago and it was unchanged, still at 16.1 Brix. I therefore added yeast energizer and continued to swirl the carboy twice daily. Now tonight, 3 days after the yeast energizer and a total of 2 weeks after pitching, it is officially a stuck fermentation - still at 16.1 Brix, corrected for an OG of 1.057. Again the FG is supposed to be 1.032. It's been at 70-71F for the last week as well. At this point, based on some reading, it appears my only option to save this will be to add actively fermenting yeast from a new yeast starter. A couple questions first.

1) How much would you add? Do you add a whole vial of yeast or a half? Do you make a 1L yeast starter or some other size? And do you try to up the gravity of the starter to match the wort currently or still shoot for 1.040?

2) What yeast strain would you add? I used WLP002. Do I add that again or try something like WLP007 for better attenuation? Or would you go with a high gravity Trappist strain or even something clean like WLP001?

 

I wanted to update this, not so much because anyone cares, but in case someone searches these threads with a similar question. Hopefully this will help. I did some research and decided to make a 1L starter with WLP001. I went for a standard gravity starter of 1.040 and put it on a stir plate for 24 hrs before pitching. It showed minimal activity for a day at most with barely any krausen or airlock activity. I checked the gravity tonight after four days and it dropped from 1.057 to 1.037. The expected FG was 1.032, so it's almost there and certainly will be drinkable and not the dreaded drain pour.

 

Yep. I chose WLP001 because of it's neutral profile (allowing the English Ale to dominate the flavor), it's high alcohol tolerance, and it's not as flocculent as WLP002. I think that's why this beer got stuck in the first place, the high flocculation of 002.