Originally Posted by Bad_Horse_Brews
Can you elaborate?
The potassium sorbate is going to inhibit the growth of mold and yeast. This will prevent things from growing in your unfermented wort. That will prevent the build up of alcohol.
Campden tablets, which are sodium metabisulfite, will inhibit yeast from reproducing and pretty well inactivate them. Since sulfites will dissipate relatively quickly (think 12 to 24 hours for typical brewing applications), any yeast still left viable MAY start to ferment again.
The addition of some potassium sorbate will help to prevent this from happening, but is not likely to stop the yeast levels that could be present before the addition of the Campden tablets.
Think of the sulfites as being REactive - offing little buggers already there - and sorbate a as being PROactive - prevent little buggers from growing in the future.