ABV from one SG?

The most common way to calculate ABV (Alcohol By Volume) is through some correlation between Original Gravity (OG) and Final Gravity(FG).

Is there any way to calculate ABV just from the current specific gravity reading?

Example - a week into fermentation you can read an sg of 1.038. Is it possible to deduce the current ABV from this using just a hydrometer and as much fancy math as you can imagine?

Topic specific-gravity original-gravity alcohol-content fermentation homebrew

Category Mac

1
answered at

As Evil Zymurgist said, you can estimate OG and ABV based on uncorrected refractometer reading and final gravity, more precisely :

The formula is the following : calculation formula

Complete explanation can be found in : http://www.moundtop.com/alcohol/Alcohol-via-Refractometer-Hydrometer.pdf

which is based on the papers :

Rogerson, F. & Symington, C. (2006). A method for the estimation of alcohol in fortified wines using hydrometer Baumé and refractometer Brix. American Journal of Enology and Viticulture, 57, 486-490.

Son, H.S., Hong, Y.S., Park, W.M., Yu, M.A. & Lee, C.H. (2009). A novel approach for estimating sugar and alcohol concentrations in wines using refractometer and hydrometer. Journal of Food Science, 74, C106- C111.

1
answered at

Actually there is a way to estimate the OG on finished beer. Then calculate ABV normally.

However it needs both a hydrometer reading and a refractometer reading, and some fancy math.

A couple programs have this formula built in.

Brewzor Calculator for free app Androids. Beer Smith for PC ( possibly in mobile versions IDK)

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