No headspace extending fermentation

I have 2 brews

Both brewed at the same time, 6 weeks ago. 2 weeks into fermentation I added sanitized wort to the one on the left. It krausened again and left the carboy almost filled up to the neck.

Beer A finished bubbling 4 weeks ago, about when I added wort to beer B. Beer B is still bubbling slowly, 4 weeks after the addition of new fermentables...4 weeks.

I assumed 2 weeks ago that it must be infected. Ths SG suggested that it was not done fermenting, and the sample tasted good but sweet.

Another sample last night tasted really good and not as sweet, SG still too high to be done.

Is it possible that the lack of headspace is slowing fermentation?

I dunno but I am interested to find out.

Why are you adding wort to already fermenting/ fermented beer? I doubt the lack of headspace is slowing the fermentation, more likely your yeast is crapping out. The healthy happy good yeast have fermented your beer and then flocced out, you add more wort and only the unhealthy slow yeast are still putzing around in your beer.

Those bottles look like regular 5 gallon water bottles and your adding wort after its completed primary?
I think I would recommend attaching a blowoff to address the main inquirey.

Cheers
BeerCanuck

Can you explain why you are adding additional wort after fermentation is complete? Are you trying to make a very high alcohol beer?

RichBrewer said:

Can you explain why you are adding additional wort after fermentation is complete? Are you trying to make a very high alcohol beer?

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That would normally be it, but with this one I just wanted it to be a little bigger than it was. I am a fan of experimentation, so if this makes it a little worse, so be it. I am glad to know of the results. It will be good regardless, and I firmly believe that it tastes better after the dark addition,

The more I think about it, Co2 will blow the side out before it is slowed by a lack of headspace, tired yeast is probably the culprit.

So, is the dark layer what you added or just an optical illusion? I ask, because if the former, the only fermentation occurring would be at the interface of the layers. Some rousing & mixing might be in order.

david_42 said:

So, is the dark layer what you added or just an optical illusion? I ask, because if the former, the only fermentation occurring would be at the interface of the layers. Some rousing & mixing might be in order.

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Excellent observation. The picture was taken 2.73 seconds after the addition. (give or take 3 millionths of a second)

The entire batch is now a very dark brown. Separation would be astounding. It is not so. It has slowed since.
The yeast, I might add, is White lebs Irish Ale yeast. One that I have personally found to be incredibly vibrant and resilient. It once (through similar step fermentation) coaxed an imperial stout to over 12% ABV, well beyond it's advertised ability.
So I am skeptical that an experiment like this one would "poop it out". But who knows. Temps are lower by 4F than that experiment.