LiquidLunch5211
Well-Known Member
Is it possible to calculate ABV after beer has been carbonated if I have OG?
Abv
- Thread starter LiquidLunch5211
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forstmeister
Well-Known Member
LiquidLunch5211 said:
If you have the OG and feel you can safely assume the FG then you can calculate the ABV. Most of my beers finish around 1.010 unless I am aiming higher.
LiquidLunch5211
Well-Known Member
forstmeister said:
The pre boil was 1.105
OG 1.062
I measured FG at 1.035
If my calc is right it's only roughly 3.4%
I was just wondering if I could take another reading but its already carbonated
I would pour a beer and let it go flat (you could help it along through agitation), then measure the gravity of the now flat beer.
Will it be perfectly accurate, not sure. Will it get you close, I would think so.
Will it be perfectly accurate, not sure. Will it get you close, I would think so.
This.
Just make sure you account for temperature, if the sample is still cold then you must adjust for the difference (there's calculators out there for this) as hydrometers are set for 60f or 65f. Otherwise your reading will be out (too high, if it's below 65f).
LiquidLunch5211
Well-Known Member
Psych said:
I use a refractometer does temp make a a difference?
forstmeister
Well-Known Member
LiquidLunch5211 said:
Refractometers do not measure fermented wort accurately. You need a hydrometer for that.
LiquidLunch5211
Well-Known Member
forstmeister said:
Ok thanks is my math accurate for final ABV
cluckk
Well-Known Member
LiquidLunch5211 said:
It looks right.
(( (OG-FG)*105)*1.25)=ABV
forstmeister
Well-Known Member
cluckk said:
I am so lazy. I haven't calculated abv in forever. Once I put brewing software on my phone and computer I gave up doing actual math.
No. Not if measured with a refractometer.
A refractometer works because of the way light refracts in it. When alcohol is in the mix, this is completely inaccurate. There are some calculators that you can use to estimate actual FG with some formulas that should account for alcohol in the mix (which skews the reading), but I've never had one that was accurate.
LiquidLunch5211
Well-Known Member
Yooper said:
All these numbers were from the brew day with refractometer. I just thought this beer had more ABVs then what I came out with and wanted to double check.
But your FG, if taken with a refractometer, is wrong. Not even close to accurate. Unless you did take it with a hydrometer- then it would be correct.
LiquidLunch5211
Well-Known Member
Yooper said:
I just measured the brew with a hydrometer and its says 1.037 carbonated but flat and room temp. I am sorry if theses are poor questions but can u explain how to calculated the final gravity accurately to me please I think I am doing something wrong. Thanks
If it's flat, the 1.037 is the FG. That's awfully high, but that's another issue.
With 1.037 as the FG and 1.062, the formula is (1.062-1.037) x 131= ABV
so, that's 3.28% ABV
With such a high FG, there was something wrong with the fermentation. It's too late now to fix it, but please be aware of the possibility of bottle bombs.
for next time, make sure you don't rack or bottle the beer until it's actually finished and at an acceptable Fg.
LiquidLunch5211
Well-Known Member
Yooper said:
Ok it was in primary for 7 days and secondary for 14 days and in the keg conditioning for 7 days before I put it on tap. I gues from what your saying is it was not finished fermenting?
Or, if it was, that something caused it to be stuck. Depending on the type of beer, I'd expect a FG of 1.010-1.016 or so. For some sweet stouts, 1.020 would be ok.
LiquidLunch5211
Well-Known Member
Thank you for the info
You can do this with MATH?! What the what!
