National Homebrew Club Ireland

Brewing Discussions => All Grain Brewing => Topic started by: hassettbrew on August 13, 2014, 01:39:54 PM

Title: Calculate estimate gravity
Post by: hassettbrew on August 13, 2014, 01:39:54 PM
I am trying to figure out how to get the estimated gravity, any help would be great thanks
Title: Re: Calculate estimate gravity
Post by: ferg on August 13, 2014, 01:50:17 PM
Original Gravity you mean?? I would normally use the calculator on BeerSmith which you can get a free one month trial of.. or use online calculators (BeerSmith can be VERY complicated on first use). Just plug in the weight and type of fermentables, assume your efficiency is 75% and it should give you an approximate OG. Plug in what yeast you plan on using and it will have figures for the attenuation of that yeast which will give you and approximate Final Gravity.
Title: Re: Calculate estimate gravity
Post by: LordEoin on August 13, 2014, 01:54:22 PM
(OG-FG)/7.46 + 0.5=ABV%

Original gravity reading less final gravity reading (in whole numbers), devided by 7.46. Add half a percent if bottle conditioning (because of the extra sugar)

Eg:
OG - 1.040
FG - 1.010

(1040 - 1010)/7.46 + 0.5
= 30/7.46 + 0.5
= 4.02 + 0.5
= 4.5% ABV

there are many calculators also like http://www.brewersfriend.com/abv-calculator/ (http://www.brewersfriend.com/abv-calculator/)
Title: Re: Calculate estimate gravity
Post by: hassettbrew on August 13, 2014, 02:55:11 PM
Good stuff, thanks for your help
Title: Re: Calculate estimate gravity
Post by: winstonia on August 13, 2014, 03:20:01 PM
Quote from: LordEoin on August 13, 2014, 01:54:22 PM
(OG-FG)/7.46 + 0.5=ABV%

Original gravity reading less final gravity reading (in whole numbers), devided by 7.46. Add half a percent if bottle conditioning (because of the extra sugar)

Eg:
OG - 1.040
FG - 1.010

(1040 - 1010)/7.46 + 0.5
= 30/7.46 + 0.5
= 4.02 + 0.5
= 4.5% ABV

there are many calculators also like http://www.brewersfriend.com/abv-calculator/ (http://www.brewersfriend.com/abv-calculator/)

Which one is right I was wondering as using the link with those numbers shows 3.94%
Title: Re: Calculate estimate gravity
Post by: MisterBurns on August 13, 2014, 03:36:08 PM

Which one is right I was wondering as using the link with those numbers shows 3.94%
[/quote]

The link isn't accounting for the sugar used for priming the bottles which is the +0.5% in Lord Eoin's calculations so in reality it's only 3.94% vs 4.02%
Title: Re: Calculate estimate gravity
Post by: LordEoin on August 13, 2014, 03:44:01 PM
yeah, I wouldn't worry about 0.1% difference.
There'd be more of a difference with incorrect hydromoter readings, wort temperature, etc.