About This Calculator
All of the formula’s used in this calculator have been derived from the following Formula from Ray Daniel’s book, Designing Great Beers.
Beg Volume * Beg Gravity = End Volume * End Gravity
**It should be noted that in the following formula’s, ‘Gravity Points’ are used in place of the beers actual Specific Gravity. (IE – 1.055 = 55)
As already mentioned above, the dilution formula is simply a derivitive of Ray Daniels formula modified to find our target gravity.
End Gravity = (Beginning Volume * Beginning Gravity) / End Volume
The above formula has been modified slightly to accommodate multiple additions to your starting wort volume.
To do this, we simply find our final volume from all 3 additions and then apply the above formula for each and combine them together to find the average gravity of wort after all 3 additions have been made.
To help illustrate how this modified formula is applied, Let’s run through a quick example using the default values from the above calculator.
Volume 1 Gravity = (3 * 70 gravity points) / 5
Volume 1 Gravity = 42
Volume 2 Gravity = ( 2 * 0) / 5
Volume 2 Gravity = 0
Volume 3 Gravity = (0 * 37) / 5
Volume 3 Gravity = 0
All we are doing with the above calculations is trying to find the weighted averaged for each addition.
From here, simply add the results together and then convert that number back to proper Specific Gravity format.
End Gravity = 42 + 0 + 0
End Gravity = (42 / 1000) + 1
End Gravity = 1.042
The Boil-Off formula is used to calculate what your ending gravity will be after you boil it down to your target volume.
Ending Gravity = (Beginning Volume * Beginning Gravity Points) / End Volume
Volume Change Formula
The volume change formula will calculate your target volume if you have a desired gravity you are aiming for.
This formula and the calculator above can be applied for both water top-off and dilution scenarios.
New Volume = (Beginning Volume * Beginning Gravity Points) / Ending Gravity Points