Gravity Reading

When taking a gravity reading, will there be a different reading if beer is carbonated compared to non carbonated?

You need to degas the beer before taking a hydrometer reading. If you don't, the reading won't be accurate due to the bubbles attaching to the hydrometer.

What is "to degas" ?

Stir vigorously until the carbonation is gone. Allowing it to rise to room temperature helps as well. When you no longer see any effervescence after agitating it has been degassed.

There is no reason to take a gravity reading after carbonation. As Bob said, the bubbles will come out of solution and attach to the hydrometer, affecting the reading.

The only reason we take gravity measurements at all is 1) to tell when fermentation has finished and 2) to estimate the alcohol percentage in the finished beer. For 1)  the measurements should be done before carbonation. For 2) the alcohol percentage will not change after carbonation. As a result I don't see any reason to measure the gravity after carbonation. Measure it just before carbonation and it tells you everything you need to know.

--GF

The reason i asked this question is because i'm the new owner of a fermentasaurus, awesome fermenter. I made my first batch with it,  and the only way to get my final gravity was when the beer was carbonated. The fermenter ferments under a controlled pressure and the beer ends up carbonated. You can check out this fermenter at morebeer .com  .  I did end up with a lower f.g. reading than normal 1.008 carbonated. Next time i will stir to degas like Bob357 said.

OK, I understand now. That looks like a very interesting fermenter. I have seen similar ones advertised, with yeast collection bottles that attach to the bottom and the claim is that you can drop out your yeast/trub without exposing the beer to any oxygen. Is there a way to purge the  bottle of oxygen first? Otherwise a bottle full of air will bubble up through your beer when your yeast drops into the bottle.

--GF

GigaFemto said:

OK, I understand now. That looks like a very interesting fermenter. I have seen similar ones advertised, with yeast collection bottles that attach to the bottom and the claim is that you can drop out your yeast/trub without exposing the beer to any oxygen. Is there a way to purge the  bottle of oxygen first? Otherwise a bottle full of air will bubble up through your beer when your yeast drops into the bottle.

--GF

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There are 2 ways to do it. 1 put water in the bottle. 2. And how I do it. Is put CO2 in it for a couple seconds and put the cap on. When I get to the fermentor I just screw it on and then open the valve. It does bubble up to the top but i figure it breaks loose some things as well to get more stuff falling down. You can also put hopps in the bottle and then put co2 ontop then dry hop. the hops will float to the top then when saturated fall back into the bottle. I am a new brewer but bought 2 of these at the reccomendation of my home brew store and have been happy so for. only 1 pressure kit at this point but will be buying a second.