Can I measure the specific gravity of finished beer?

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Beerbeque

Beerbeque

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Will a hydrometer reading measure the specific gravity of finished and carbonated beer or must I first decarbonate ( is that a word?) the beer.
I ask because I would like to measure some commercial beers and compare them to my homebrews.
 
I think the bubbles sticking to the hydrometer would throw things off, but if you flatten the beers first it should work.
 
Does this mean that taking a hydrometer reading early (before fermentation has finished) will skew results? There is often some carbonation when I do a reading.
 
doulovebeef said:
wait, if you want to take hydrometer readings on commercial beers, wouldnt you have to have an OG first?
Click to expand...

Only if you wanted to know what the ABV is, which, I assume, is not the case here. You could want to know what the final gravity is to help build a clone. For example, to choose the proper yeast and starting gravity in your recipe.
 
Dauntless said:
Does this mean that taking a hydrometer reading early (before fermentation has finished) will skew results? There is often some carbonation when I do a reading.
Click to expand...

If you take a hydro reading before your beer has finished fermenting, then yes your FG would be skewed. However, you should be using your hydro to determine if your fermentation is complete. You take separate hydro reading a couple of days apart. If they are the same, then you know you have the true FG, and it's time to bottle.

I'm guessing when you say you take a hydro reading when there is still carbonation you mean that the beer is still producing some CO2 in the fermenter. This will almost always be the case. Hence, the reason you take the hydro readings to be sure fermentation is complete.
 
A trick to speed up degassing is to pour the beer back and forth in between glasses, do this 50 times. You can degas a sample of beer in a couple of minutes this way. :mug:
 
Post fermentation and pre-carbonation your homebrew beer is already ballpark half carbonated, yet this is the environment in which homebrew FG's are taken. Fully decarbonating a commercial brew in order to determine its FG for comparison purposes is by this standard clearly a mistake.
 
In order to reduce chances that bubbles will nucleate on the surface of your hydrometer, you can clean it with salt. The abrasiveness of salt will remove most tough residues that would precipitate nucleation.
 
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