Is it possible to estimate final alcohol value from the orginal gravity of the wort? Is apparent attenutaion involved in the estimation?
I guess if I know OG and FG this is the answer. What if FG is not know?
Alcohol is the product of anaerobic respiration, the consumption of sugars by yeast. If you had access to a chemistry lab, you could measure the alcohol directly, but most calculate their alcohol by calculating the quantity of sugar that has been consumed. For the most part, this is done by comparing the OG to the FG.
In other words, the OG by itself will not tell you how much alcohol there is. You need to either measure or estimate the FG. If measuring is not an option, you can use your expected attenuation to estimate it.
FG = (OG - 1.000) * (apparent attenuation) + 1.000
From there, you can use any of the ABV estimation formulas.