Brix to ABV/Proof Plot

[Blackbeard83]

Hello all, I couldn't find a quick-reference resource that correlates an ethanol + water Brix reading to a corresponding ABV/Proof, so I made the attached plot. Plot was validated against tests with a floating alcohometer. Inspired by viewtopic.php?t=70357

This plot was developed using lookup tables from various online sources that correlate sugar and ethanol to refractive index (UNIQUAC standard), and a table of alcohol by weight vs alcohol by volume at the standard temp of 20C. Conversion is: Brix -> Refractive Index -> Ethanol by weight % -> Ethanol by Volume. I used trend lines to interpolate the table data so it's not perfect, but the center section should be really close (ethanol regression line is 6th order so ends were inaccurate and I had to hardcode 0 Brix and 21 Brix refractive index values). Spreadsheet is included so you can see the methodology.

I've seen some refractometers made for distilling have this scale built in, but this chart should help people who only have a refractometer with the Brix scale.