**thread**:

In answering, I compared my calculation against thejust curious -- which ABV calc method do you tend to use?

**FermCalc Javascript**page, and found a few problems. This topic is worth exploring on its own.

My answer to Bmd2k1's question is that I use the following formula. I created an worksheet function in Excel, which round the answer to 3 decimal places, which Excel displays as a decimal.

ABV = (InitialGravity - FinalGravity) / 7.36 * 10

For OG = 1.100 and FG = 0.994, this produces 14.4%.

Using the Javascript FermCalc page, I get:

14.5% Berry

14.4% Duncan & Acton

14.1% Balling

14.6% Cutaia, Reid, & Speers

I checked

**FermCalc's formula description**-- the formula I use is Berry, which they list as: av = (sgi – sgf) / 0.00736. In English, sgi = InitialGravity, sgf = FinalGravity

This formula produces the same answer as the one I use, the difference is the decimal place is in a different location. I verified FermCalc's formula in a calculator, to ensure the results are not affected by Excel or Javascript. This produces 14.40217391304348, which rounds to 14.4%.

However, FermCalc's Javascript page produces the wrong answer, 14.5%.

Since I found one error, I checked Duncan & Acton. This is more complicated, as it requires 3 formulas, as the results of #1 are used in #2, and the results of #2 are used in #3:

sgc = sgi – 0.007

F = 7.75 – 3000(sgc – 1.0) / 800

av = 1000(sgi – sgf) / F

Executed in Excel for the above values, I get 14.3. Instead of being high like Berry, this one is low.

Ok, on to the next 2. Balling and Cutaia are not wine formulas, they are beer formulas. I've read in numerous places that different formulas are required for different ABV ranges, as the curve is not an even one. Beer formulas (ABV in the 4% to 8% range) are supposed to be different from the wine ranges. This may explain why these two produce low and high results, respectively.

At this point, I have no trust in FermCalc, as the Javascript calculators produce wrong answers. This is very sloppy programming.