Degassing and it's effects on yeast

I'm wondering if degassing and removing the suspended CO2 (a part of, and a percentage of the wine) changes the totals for ABV% as it applies to yeast tolerance. It seems that by degassing you would inherently increase the existing ABV% because there is less total parts then when you started off before degassing. Even if 1% of the mead/wine is CO2, and it's released through degassing, that would mean the ABV would increase.

On the flip side, by removing one of the two toxins(ethel alcohol CO2)from the yeast, does this give them more room and less stress to ferment further? Since CO2 is toxic to yeast, does it inhibit the yeast's ability to fully ferment the larger amount of sugars in wine/mead?

Topic degassing co2 wine mead yeast homebrew

Category Mac

1
answered at

ABV is Alcohol By Volume. Carbonation does not change the volume. So it would not effect the ABV.

c02 is dissolved into the liquid. Meaning that the c02 molecules fit in between the liquid molecules and do not change the total volume of the liquid. As long as the c02 is trapped the liquid volume is unchanged, once released (bubbles) the gas displaces liquid volume making a larger total volume which can cause issues with volume calculations during this phase of release.

1
answered at

I have tested this personally and have not been able to record any perceivable differences in SG readings. Sometimes degassing will invigorate a slow ferment but nothing more than a good stir would. I do see your math behind the ABV increase and I still believe that to be true as well.

Degassing is something you should be doing throughout primary and into secondary. CO2 can be toxic to yeast, stressing them out, and potentially producing some off flavors and aromas. Keep in mind, degassing is different than aeration; you're just trying to get the dissolved CO2 out of solution, not to whip the crap out of it. Basically, do it a few times during primary, before each SNA addition. Adding nutrients and then degassing is a sure way to end up with partially fermented honey all over your floor. I repeat: Degas and THEN add nutrients. I then tone it down a bit for the secondary until fermentation is over and CO2 stops being released from the process.

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