Quote:
Originally Posted by helgibelgi
Am I right in thinking that the final gravity reading, using a hydrometer, will be skewed? Because the solution is now not only water and sugars, but also alcohol which is lighter than both water and sugar.

You are absolutely right.
Quote:
Originally Posted by helgibelgi
So I understand that by comparing OG to FG you get Apparent Attenuation. But that number seems to me to be useless.

Stand by on this for a moment.
Quote:
Originally Posted by helgibelgi
What you want is Actual (or Real) Attenuation. That way you can know exactly the amount of sugars that have been converted into alcohol.

Yes, that is what you want if you are willing to do the extra work to get the true extract. Reunited with my library now so
ABW = (.48394 +0.0024688*p + 1.5609E%*P*P)*(Pn)
where P is the original extract and n the true extract.
But if you don't have the true extract another, even more approximate, formula is available which take into account the effects of alcohol on the AE measurement
ABW = (0.39661 + 0.0017091*P + 1.0788E5*P*P)*(Pm)
where m is the apparent extract.
The formulas for the difference multipliers are fits to "Ballings Table", Table 15, DeClerck Vol II p 428