How to calculate ABV Options

[Vinman]

On my hydrometer, it says to simply subtract the FG from the OG and that will give me the ABV. I have also heard to subtract FG from OG and multiply by 131. Which is correct?

My last batch of all-grain had an OG of 1.05 and a FG of 1.00. According to the hydrometer's instructions, that is 5% ABV. If I multiply by 133, the ABV is 6.55. Based on the taste, I think the 5% is correct. Anyone know?

This post has been edited by Vinman: Mar 13 2013, 09:59 AM

[BardsBrew]

On my hydrometer, it says to simply subtract the FG from the OG and that will give me the ABV. I have also heard to subtract FG from OG and multiply by 131. Which is correct?

My last batch of all-grain had an OG of 1.05 and a FG of 1.00. According to the hydrometer's instructions, that is 5% ABV. If I multiply by 133, the ABV is 6.55. Based on the taste, I think the 5% is correct. Anyone know?

You must multiply the difference in gravity readings by 131. Gravity readings should be taken @ 60 degrees or you must adjust those also.

Cheers!

[pilsenhammer]

If your last batch had a 1.050 OG and a !.000 FG then you might want to check the accuracy of your mashing thermometer. 1.000 on any beer is a really fermentable wort. You may be mashing at lower than desired temp. BTW, if your gravity measurements are correct, the beer is 6.57% according to ProMash.

[organicbrewer]

Using specific gravity. {(Starting gravity) minus (Finishing gravity)} divided by 7.5=alcohol by volume