Originally Posted by Walker
Extract should not be affected by efficiency.
This is correct but the Brew Builder does not have the ability to ignore that rule when extracts are concerned. To compensate for this the potential gravities of all extracts have been adjusted so that when 75% efficiency is chosen the values of the OG will be correct.
Example: 1 pound of Pilsen Liquid extract at 75% efficiency yields 1.038 per gallon which is correct value for that extract. If you change the efficiency from 75% your OG will be off.
So the bottom line is if your an extract/PM brewer do not change the 75% and everything will be correct. If your a PM brewer that gets higher or lower than 75% the corrected value is 2-3 points for every 5% you are higher or lower than 75%.