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[Flamewhisperer]

I wish I'd found this site when I first got started brewing about three years ago. It's been a slow climb from a kit with LME and a five-gallon bucket in the closet to all grain brewing in a corny keg with a kegerator for temp control.

I am however gonna try fermenting under pressure now and I have a question.

Is the final gravity affected by the carbonation, and if so, would that be overcome by using a prismatic gravity test instead of a hygrometer?

 

[VikeMan]

Is the final gravity affected by the carbonation, and if so, would that be overcome by using a prismatic gravity test instead of a hygrometer?

Yes, CO2 will cause a hydrometer to float higher than it otherwise would. You can pour the sample back and forth between two cups (or whatever) several times to de-gas it.

By prismatic gravity test, do you mean a refractometer? If so, I'm pretty sure dissolved CO2 can affect the refractive index of the beer, but I think the effect is small. If you do use a refractometer, be sure to use a refractometer calculator to adjust the readings.

 

[Flamewhisperer]

Yes, CO2 will cause a hydrometer to float higher than it otherwise would. You can pour the sample back and forth between two cups (or whatever) several times to de-gas it.

By prismatic gravity test, do you mean a refractometer? If so, I'm pretty sure dissolved CO2 can affect the refractive index of the beer, but I think the effect is small. If you do use a refractometer, be sure to use a refractometer calculator to adjust the readings.

Thank you. I'll do both tests on this first keg and see how they differ. I just got the refractometer for Christmas so I can test OG with both and then FG after pressurized fermentation. Thanks again.