Alcohol Calculations

[B_Bear]

I have noticed that there is 2 ways to calculate alcohol percentage.

eg.

OG 1075
FG 1018

Diff 57

Which is more accurate?

57/7.36 = 7.745%

or

57 x 0.135 = 7.695%

Or am i just being picky?

Cheers

:beer:

 

[mika]

Who cares...drink it

 

[Josh]

I don't know the answer. But you could just split the difference and divide by 7.4 = 7.70% in your example.

From memory, I use /7.4 for my crude calculations.

 

[bconnery]

I did a bit of reading on this once as family and mates would keep asking me.

You'd never guess but there are a lot of different ways that people use (go figure)!

The minusing of the various g's and dividing will get you in the ballpark. I played around with a few formulas until I found one that I liked, maybe because it gave slightly higher percentages without being way out of the ballpark like some I've seen.

Anyways, here's mine...

(OG-FG)/1000)*127.5

This is the basic one.

I also factor in a little for grams of sugar per litre used for priming...I got these figures from somewhere, I think it was an old thread on the aussie homebrewer digest or whatever it was called.

+(IF(g/l = 6,0.18,g/l=7,0.23,g/l==8,0.3,0.35))

I can't vouch for the accuracy but it seems to work OK. The milds come out mild and the strong beers come out strong abv wise...