View Full Version : Potential Alcohol Conversion calculator seems inconsistent

10-15-2010, 11:44 AM
Maybe I am using the "green box" Potential Alcohol Conversion calculator wrong, but I don't get consistent results.

Using the SG and %ABVC options
Enter 1.147 OG
Enter 1.005 FG
This calculates %ABV to 18.03

Now, Type 18.02 into %ABV. I'd expect the OG to be recalcuated but the change to be so small as to not make a difference. But the OG changes to 1.137. That's a substantial change. By entering %ABV, I do not get an OG of 1.147 until I enter 19.1.

Am I doing it wrong?

Medsen Fey
10-15-2010, 12:40 PM
I see the same thing. I'm not quite sure why that is occuring.

10-16-2010, 02:21 AM
It seems to me like this is going on:

When you type in an OG/FG pair, it calculates the %abv. When you type in a %abv, it gives you an OG to achieve that...if it ferments totally dry (below 1.000). Basically it is ignoring the input in the FG box if you enter a %abv.