I just started doing forced fermentation (FF) tests with each batch I make. I know that the final gravity of the FF beer will be lower than the final gravity of the beer fermented normally in the carboy -- but how much lower? Is there a normal range, or is it going to vary wildly?
For example, I just finished a batch of ESB. The FF beer has an FG of 1.013 and the beer in the carboy stopped at 1.016 - 1.017. Is that a normal range, or is that an indication that the beer in the carboy didn't ferment fully?