specific gravity contribution formulas - need help
Posted: Sat Nov 29, 2014 12:32 pm
by brewinhard
I recently added 64 oz of carrot juice (measured 1.0298 specific gravity with refractometer) to a 5.0 gallon batch of beer for a total of 5.5 gallons of beer/juice blend. For some stupid reason I am having trouble calculating how many specific gravity points this juice addition will add to my beer. Any help would be greatly appreciated.
Re: specific gravity contribution formulas - need help
Posted: Sat Nov 29, 2014 2:52 pm
by BDawg
64 oz == .5 gallons
What you want to do is figure out how many gravity points per addition, add those values together, then divide by ending volume.
gravity points = volume of the addition x gravity portion of that addition (ie, 1.050 -> 50)
Assuming your base beer is 1.050 for 5 gallons:
5 gallons x 50 = 250
.5 gallons x 1.0298 = 29.8/2 = 14.9
Add the gravity points together: 250+14.9 = 264.9 gravity points
Now divide by the end volume:
264.9 / 5.5g = 48.1637 or back into specific gravity format = 1.04816
So, you actually diluted the wort a little by adding the carrot juice because you added more water than sugar to the mix.
HTH-
Re: specific gravity contribution formulas - need help
Posted: Sat Nov 29, 2014 3:48 pm
by brewinhard
Thanks for the walk through tutorial Bdawg! After doing a little research myself I was able to come up with this answer but in a backwards sorta way. I now have a better understanding of juice additions and what they do to overall final gravity. You rock!
Thanks for sharing...
Cheers -
Brewinhard

Re: specific gravity contribution formulas - need help
Posted: Sat Nov 29, 2014 9:12 pm
by Klickitat Jim
brewinhard wrote:Thanks for the walk through tutorial Bdawg! After doing a little research myself I was able to come up with this answer but in a backwards sorta way. I now have a better understanding of juice additions and what they do to overall final gravity. You rock!
Thanks for sharing...
Cheers -
Brewinhard

He's rock on the outside but soft and cuddly on the inside
Re: specific gravity contribution formulas - need help
Posted: Sat Nov 29, 2014 9:35 pm
by BDawg
Ha!
