Forgot to take FG reading. Anything I can do?

[nigel31]

Hi,

I was helping a friend bottle his first brew recently and got distracted, forgetting to take a final gravity (FG) reading. Boooooooo.

Would degassing a bottle and pouring it into a hydrometer test jar work for a semi-accurate reading at this stage? If not, is there some other way to get him a good-enough FG reading so we can calculate the ABV?

Thanks.

 

[Jaysus]

You could always just drink it and not worry about it

 

[tchuklobrau]

+1 rdwhahb

 

[nigel31]

Yeah, okay, we're not worried about it or anything; he's just curious--for curiosity's sake, as it's his very first brew--what the ABV is, and I was wondering if taking a degassed reading would be accurate enough. Tanks fer nuttin'.

 

[BeerEagle]

+1 rdwhahb

Sorry, I'm a newbie to the forum, but what does RDWHAHB mean?

 

[tchuklobrau]

Relax dont worry have a homebrew. Nigel degassing would probably work. would never be totally right cause of the priming sugar and all. but go for it. if nothing else u get to drink more samples.

 

[BeerEagle]

never be totally right cause of the priming sugar and all. but go for it. if nothing else u get to drink more samples.

I've done this. Priming sugar will have increased the ABV by a fraction of a percent - maybe .3 to .6 depending on how much you added. So take the OG and the FG from your bottle work out the ABV and then add on a correcting .5 or so.

I always found this confusing on kits when they quote the estimated ABV on the pack. Could never get that number from my SG readings until I saw a hint on this forum about the little extra alcohol created by the bottling/kegging sugar.

 

[MalFet]

To figure out how many points the priming sugar added to the gravity:

(Amount of sugar in pounds) x 46
Divided by (volume of batch in gallons)

Typically, priming sugar will raise your gravity by 2-3 points. If you figure out exactly how much, you can determine what your FG was before adding the priming sugar (assuming you just bottled).

 

[dcp27]

The net difference from the sugar after the bottle is carbed should be negligible. The increase to OG is already very minimal and sugar is 100% fermentable so you could probably just take the de-gassed FG at its value.