Fermentation without visible CO2 production?

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Sep 10, 2011
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I'm experimenting with a barleywine recipe. It started at a very high gravity wort (1.114), and before the ale yeast stopped doing its thing, I added 4 lbs of inverted sugar. The fermentation kept on strong for another two weeks, using US-05.

In the mean time, I added another 4 lbs of inverted sugar to a starter of super-high-gravity champagne yeast (22% tolerance). I left both casks to mature for about a week and a half, when I added the original fermenter's contents to the champagne yeast "starter".

After this, I did not notice much CO2 bubbling at all, out of the now 6-gallon fermenter jug. I took a sample of the beer, and it was like tasting quite syrupy. I was worried that I went too far, too soon (for the yeast).

Three weeks later, after trying to stir up the yeasts at the bottom of the fermenter many times, and letting them settle, I took another sample.

Despite my witnessing ZERO bubbling out of the airlock for weeks, this beer went from tasing like cane syrup, to tasting like pure ethanol.

I ask you, my homebrewing brethren...how can yeast make so much alcohol without bubbling the hell out of their environment?

This isn't necessarily a bad thing...but did I miss something?