DocBrown
Well-Known Member
It appears that I do, in fact, have a stuck fermentation. I brewed a 5 gallon batch of AHS' Cannonball Stout (extract recipe) back on March 28. I measured the OG at 1.115. However, I realized later that my reading was probably inaccurate. I took my sample from the spigot at the bottom of my ale pail (I know, I'll get a turkey baster before my next batch!) after doing a 2.5 gallon boil and pouring additional water on top of the wort in the fermenter. I don't think I mixed it very well, as the recipe sheet from AHS predicts an OG of 1.100, and the only place I deviated from their recipe was in the addition of the BrewVint yeast fuel (in hopes of preventing what I have now!) and a whirfloc tablet to the boil.
In any case, I knew up front that this would take quite a while to finish. I had very active fermentation for a while and got a decent amount of foam coming through the blow-off tube. I didn't see any obvious signs of continued fermentation after a week, but I've read enough of Revy's cut-and-pastes to know that the level of airlock activity doesn't tell you much at all. After two weeks my SG was down to 1.040. Unfortunately, it's barely moved from that point. At 3 weeks it had only dropped to 1.039. I sanitized my brewing spoon and gently stirred the wort at least to the point where I saw bits of the trub floating back up to the surface. However, it's been another full week (the wort has been in the primary for a full month now) and the SG is still 1.038. The wort sample does have a sweet syrupy kind of taste indicative (at least in my very inexperienced judgment) of plenty of remaining sugars.
I did check and verified that my hydrometer is accurate. At worst it's off by about 0.002 depending on how pure my tap water is. I originally pitched two vials of White Labs WLP007. My fermentation temperatures have not been especially stable as north Alabama has gone from 85F down to snow and back over the last month, and my brewery closet is not especially well insulated and has no room for a swamp cooler setup. However, the temperature of the air around the fermenter has ranged from about 65F to 72F.
So I'm wondering what my next step should be. A number of threads I've read in here have implied that additional yeast may not really help since there should be plenty of yeast cells remaining. However, with the wort already at 8+% ABV, should I consider pitching some yeast with high alcohol tolerance to finish this off? Alternatively, is there a good yeast enzyme I can add to get things going again? Would 1oz or so of corn sugar give the yeast something a bit easier to work with to get going again?
Thanks for the help.
JB
In any case, I knew up front that this would take quite a while to finish. I had very active fermentation for a while and got a decent amount of foam coming through the blow-off tube. I didn't see any obvious signs of continued fermentation after a week, but I've read enough of Revy's cut-and-pastes to know that the level of airlock activity doesn't tell you much at all. After two weeks my SG was down to 1.040. Unfortunately, it's barely moved from that point. At 3 weeks it had only dropped to 1.039. I sanitized my brewing spoon and gently stirred the wort at least to the point where I saw bits of the trub floating back up to the surface. However, it's been another full week (the wort has been in the primary for a full month now) and the SG is still 1.038. The wort sample does have a sweet syrupy kind of taste indicative (at least in my very inexperienced judgment) of plenty of remaining sugars.
I did check and verified that my hydrometer is accurate. At worst it's off by about 0.002 depending on how pure my tap water is. I originally pitched two vials of White Labs WLP007. My fermentation temperatures have not been especially stable as north Alabama has gone from 85F down to snow and back over the last month, and my brewery closet is not especially well insulated and has no room for a swamp cooler setup. However, the temperature of the air around the fermenter has ranged from about 65F to 72F.
So I'm wondering what my next step should be. A number of threads I've read in here have implied that additional yeast may not really help since there should be plenty of yeast cells remaining. However, with the wort already at 8+% ABV, should I consider pitching some yeast with high alcohol tolerance to finish this off? Alternatively, is there a good yeast enzyme I can add to get things going again? Would 1oz or so of corn sugar give the yeast something a bit easier to work with to get going again?
Thanks for the help.
JB