Final Gravity 1010??

[clives-online]

Greetings,
I am still trying to get my head around this hydrometer readings.

The original gravity of my Imperial Stout was OG Gravity ==> 1.080
The final reading when I bottled some beer was on the black line..
Is that 1010 or 1001??..

If the reading is 1010, do I multiply 0.70 in the alchol calculator app??

Looking forward to words of wisdom..

 

[Leon103]

That's 1.010

 

[johncrobinson]

Cant really tel from the pic but looks to be 1.010 giving a total drop of 70 points or 9.9%abv
very strong for beer.

 

[DavidDetroit]

Yeah, as above.
Does anyone here just do (OG-FG) X 131.25?
that would put your ABV at 9.19%.

 

[DavidDetroit]

9.9%abv

What formula do you use?
I know mine, (OG-FG) X 131.25, has flaws but it's what I learned. It would give 1.080-1.010 X 131.25
an ABV of 9.19%.
thanks.

 

[clives-online]

Thanks,
Much appreciated.
Bottled for as long as possible, before opening.

 

[johncrobinson]

Its a table which is supposed to take into account the effect of dissolved substances other than sugar.
Is it more accurate than the standard formula,????????
Thats a good question.

 

[Rodcx500z]

In the brewers friend calc it is 9.19%

 

[johncrobinson]

There is another thread going about hydrometers and calculating abv this very moment .
Its worth a wee look.

 

[DavidDetroit]

Its a table

It sounds like if it's a table/not static, it may account for a sliding scale kind of thing as gravities go up or down and therefore be more accurate.
Doesn't matter too much. I'm in the ballpark, I know that.

 

[foxbat]

What formula do you use?
I know mine, (OG-FG) X 131.25, has flaws but it's what I learned. It would give 1.080-1.010 X 131.25
an ABV of 9.19%.
thanks.

The relationship is non-linear therefore that multiplier of 131.25 isn't the same for all strengths. The multipliers used by HMRC when calculating ABV for the purposes of tax are provided online which are as close to a standard as we've got in the UK. In case the link disappears, here it is:

30.2 Calculating the alcoholic strength

1. Measure the OG within one hour of collection*
2. Wait until fermentation is completed - for cask-conditioned beer this will be after secondary fermentation in the casks, then
3. Measure the present gravity (PG) (also known as the specific or final gravity)*
4. When you’ve taken your readings, calculate the alcoholic strength using the formula, (OG - PG) × f = a% ABV, where: * OG is the original gravity of the beer * PG is the present gravity of the beer * a is the beer’s alcoholic strength * f is the factor connecting the change in gravity to alcoholic strength. The value of ‘f’ is not constant because the yield of alcohol is not constant for all fermentations. In lower strength beers, more of the ‘sugars’ available for fermentation are consumed in yeast reproduction than in producing alcohol. The table at 30.3, produced by the Laboratory of the Government Chemist, shows the changing value of ‘f’ depending on the alcoholic strength of the beer

*Use a suitably calibrated saccharometer adjusted for the temperature of the representative sample.

30.3 Value of factor ‘f’ for various alcoholic strengths

(OG - PG)	% ABV	Factor
Up to 6.9	Up to 0.8	0.125
7.0 - 10.4	0.8 - 1.3	0.126
10.5 - 17.2	1.3 - 2.1	0.127
17.3 - 26.1	2.2 - 3.3	0.128
26.2 - 36.0	3.3 - 4.6	0.129
36.1 - 46.5	4.6 - 6.0	0.130
46.6 - 57.1	6.0 - 7.5	0.131
57.2 - 67.9	7.5 - 9.0	0.132
68.0 - 78.8	9.0 - 10.5	0.133
78.9 - 89.7	10.5 - 12.0	0.134
89.8 - 100.7	12.0 - 13.6	0.135

The table indicates that for the majority of popular UK beers, the factor for calculating the estimated strength would lie in the range 0.129 and 0.130. For strong beers (exceeding 6% ABV), the factor would be in the range of 0.131 - 0.133. Whilst it is important that the correct value for ‘f’ is used, you should be aware that this table is primarily for your guidance. Some brewing methods and materials can affect the factor. If in any doubt you should seek more advice - see below.

 

[MrRook]

I'm not sure where I came up with it but I take the amount of gravity drop and decide by 7.5 which in this case comes out to 9.33%: close enough for government work.

 

[DavidDetroit]

In the brewers friend calc it is 9.19%

That's what I got with this: (OG-FG) X 131.25.
I've asked numerous times if someone has a formula that doesn't require a lot of steps and may be more accurate but nothing so far. As I said above, I'm aware that my formula has flaws.
It's mostly curiosity.