hungupdown
Well-Known Member
Doing a brew where sugar has to be added as ferment progresses, and wondering if anyone knows a good way to find the corrected FG(SG) from brix ?
Brew is a strong imperial stout, Target 14.3% ABV, post boil gravity 1130. Up to 2kg dextrose is gradually added as ferment progresses, that's up to around 5% of the alcohol. This is so yeast is not stressed by an extreme OG, and you can quit additions if fermentation stalls, before reaching 14.3% (rather than ending with something far too sweet).
I normally use the brewersfriend calculator, that takes figures for OG brix, and FG brix, to give the corrected FG(SG) & ABV, but don't think it will give valid results directly, where sugar is added between the readings entered.
Can the calculator be made to work, by increasing the OG entered, by the SG change the added amount of sugar would give?
eg:
OG - (Brix WRI): 31.4 ; Wort Correction Factor: 1.04 ; OG - Corrected 1.130
2 days: brix 17.6% ; Wort Correction Factor: 1.04 ; FG - Corrected 1.035 ; ABV 11.86% ☆
Dextrose addition 185g ; Fermentation volume 20L ;
Dissolved sugar 9.25 (g/L) ; would give Specific Gravity 1.00362 (or 3.6 gravity points, round up to 4). Vinolab gravity-density-sugar converter
Then putting OG 1.130 + .004 = 1.134
5 days: brix 17.5% ; Wort Correction Factor: 1.04 ; FG - Corrected 1.034 ; ABV 12.40%
A hydrometer reading on day 5, was close at 1.035 (inc. temperature correction), so looks promising.
The second sugar addition, 200g, is now in.
So for my next readings, I'd calculate for the total added dextrose 385g; 19.25(g/L) ; SG 1007.47 (or 7 SG points) ; OG =1.130+.007 =1.137
☆ At high alcohol levels, an uncorrected brix conversion is way off: 2 days, brix 17.6% : uncorrected conversion SG=1.072 (Vinolab); vs 1.035 corrected (brewersfriend).
Brew is a strong imperial stout, Target 14.3% ABV, post boil gravity 1130. Up to 2kg dextrose is gradually added as ferment progresses, that's up to around 5% of the alcohol. This is so yeast is not stressed by an extreme OG, and you can quit additions if fermentation stalls, before reaching 14.3% (rather than ending with something far too sweet).
I normally use the brewersfriend calculator, that takes figures for OG brix, and FG brix, to give the corrected FG(SG) & ABV, but don't think it will give valid results directly, where sugar is added between the readings entered.
Can the calculator be made to work, by increasing the OG entered, by the SG change the added amount of sugar would give?
eg:
OG - (Brix WRI): 31.4 ; Wort Correction Factor: 1.04 ; OG - Corrected 1.130
2 days: brix 17.6% ; Wort Correction Factor: 1.04 ; FG - Corrected 1.035 ; ABV 11.86% ☆
Dextrose addition 185g ; Fermentation volume 20L ;
Dissolved sugar 9.25 (g/L) ; would give Specific Gravity 1.00362 (or 3.6 gravity points, round up to 4). Vinolab gravity-density-sugar converter
Then putting OG 1.130 + .004 = 1.134
5 days: brix 17.5% ; Wort Correction Factor: 1.04 ; FG - Corrected 1.034 ; ABV 12.40%
A hydrometer reading on day 5, was close at 1.035 (inc. temperature correction), so looks promising.
The second sugar addition, 200g, is now in.
So for my next readings, I'd calculate for the total added dextrose 385g; 19.25(g/L) ; SG 1007.47 (or 7 SG points) ; OG =1.130+.007 =1.137
☆ At high alcohol levels, an uncorrected brix conversion is way off: 2 days, brix 17.6% : uncorrected conversion SG=1.072 (Vinolab); vs 1.035 corrected (brewersfriend).
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