Birch Beer carbonation troubles

Is anyone aware of something in Birch Root Beer extract (Old Fashioned Homebrew brand I believe) that could be toxic to yeast? I've made many successful batches of root beer, naturally carbonating with yeast - but I've tried 4 batches so far with this Birch Root Beer extract and it just doesn't happen. I've tried waited 2 weeks @ 70 degrees, adding more yeast, warming it up, agitating the bottles daily - everything else about the recipe is the same except for the extract. Anyone else had the same problem?

first guess would be sanitation. how did you sanitize and sterilize the bottles?

second guess is seals. is there an airtight seal? did the bottlecaps get fouled in some way?

third guess is yeast. how old is it? how was it stored? was it hydrated properly before using?

i doubt its the extract. since they are meant to be used with yeast recipes.

good luck

I use Iodophor and sterilize exactly the same way I do with root beer and beer. Everything is exactly the same as other successful batches, it just doesn't work when I use that particular extract. I've tried it 4 separate times now...with successful root beer batches in between. At this point there's really nothing else it could be but the extract. Never had a soda batch fail before and I've made it for several years.

Odd, the one time I made birch beer it carbonated, not heavily, but then I don't want much carbonation with birch beer. I'm certain it was "Old Fashioned Homebrew" extract that I used.

If you have some of it still around, why not pour a bottle into an open container and let is sit at 80F for a few days? Check to see if the gravity changes.

I don't need it as heavily carbed as root beer, but it's barely doing anything. Last 3 batches had almost no discernible carbonation after 2 weeks @70, and usually my root beer is carbed within 4-5 days.

As an update, I added some extra yeast to the bottles (PET) last night and they're gaining a little bit of pressure as of this evening. Basically I doubled the amount I would normally use, we'll see if they get anywhere.