johnsnownw
Well-Known Member
I did brew the extract recipe exactly as is.
I did the reading pre bottling - so de-gassing wasn't the issue.
This was actually my first yeast starter, active fermentation was great. I live in Boston in an apartment so I don't have enough space to control temperature but I know it's been consistently at 64-66 degrees.
There is C02 in suspension, after primary and secondary. It's why you have to de-gas wine prior to bottling. So, that could have been a factor.
As to the starter, it depends on your procedure. If you pitched an older vial of yeast, and the starter hadn't propagated enough yeast, you would have under-pitched. This can cause the beer not to fully attenuate. Yeast health is difficult to determine if you're using air-lock activity as an indication. I'm not saying you didn't have healthy yeast, but if your measurement was correct, then something is causing the lower than expected attenuation.
If it was an ambient temperature in the room of 64-66, then the temperature of the wort could have risen by a factor of 5-7 degrees. This is because the yeast are exothermic. Though, generally warmer temperatures, if not too warm, aid in attenuation. So I do not believe the temperature was a factor here...unless you pitched the yeast warm or something.
Now, something you need to pay attention to. If your measurement was correct, and the yeast stalled, there is the possibility that during priming the yeast will continue where they left off. That is, they may eat all the priming sugar, and then move on to the sugars it didn't finish before. This could create an over-carb issue, and possibly lead to bottle bombs. I would suggest putting those bottles into a rubber/plastic tote, in case this does happen. You do not want to clean up a bunch of beer off the floor. Make sure to be careful when opening as well.