Champagne yeast or wpl099 to finish a 1.102 IIPA?

[Brewmex41]

I was wondering if using champagne yeast would finish off an IIPA with an OG of 1.102 if the pacman yeast doesn't get it below 1.020
I brewed a 5 gallon batch of 1.090 starting, then added a gallon of white grape juice bringing my OG up to 1.102
If it finishes above 1.020 I wanted to add champagne yeast to get it dryer, but will the champagne yeast be able to eat anything that's left or should I give the high gravity yeast a go? It's still fermenting, as I just added the second half gallon of juice this morning, but if I need to build some yeast id like some thoughts.

 

[Fionnbharr]

Let me start with the disclaimer that I haven't added fresh fermentables after I started fermentation. The addition of the white grape juice makes this question both excellent and moot.

What I do know is that most of the flavors contributed by yeast happen at the beginning of the fermentation process. If one starts with a high-gravity wort, the primary yeast does the bulk of the fermenting and flavor-contributions, and any high-gravity workhorse yeast may be added as a secondary to bring the FG down to where it should be.

Champagne yeasts are generally 'high-gravity' yeasts, and would do a good job of finishing the fermentation. Dry yeasts are cheap, but should be primed in water before adding. High-gravity beer yeasts (pick your favorite), do the same thing, and if already a liquid slurry won't add as much liquid. In either case, you need to think about cell count, and add appropriately.

I think it's a brewer's judgment call; the biggest unknown is the quality of grape juice (including preservatives if you're using a commercial juice), or other yeasts the grapes might bring to the party.

Keep us informed. I'd like to know how it turns out.

 

[Brewmex41]

I already bought the champagne yeast, but I didn't realize it wouldn't be effective at eating anything other than simple sugars that might be left if the primary yeast didn't get to them. I can usually get 80-84% AA from pacman, but that's usually brews at 1.070 or less, never tried one this big. I don't really want a sweet Ipa. I used half pound corn sugar at the end of the boil, and mashed at 148 for an hour, but I added carapils which I got the idea from Pliny the elder, which I clones a while back.
That and juice which should mostly ferment out will hopefully bring the fg way down, but we shall see.

I made sure to buy juice with nothing but grape juice and added vitamin c, since its added to almost all juices, and none of the potassium meta...whatever it is they add to most non organic juices.