I have long wished (as have many others I am sure) that there were an easy way to calculate actual ABV of a finished product but always believed it required more complex lab equipment than I am willing to get involved in.
Recently a friend came across a couple of different sites offering a calculation that should yield ABV based off of Hydrometer and Refractometer readings of the finished brew. VinoCalc has one here
It seems too good to be true
Does anybody understand the science behind this enough to endorse it? Are there any caveats such as only working for liquids with little to no residual sugars?
Ultimately I would like to use on off-dry ciders as well as dry wines.
Thanks for any insight.