Originally Posted by borderless
If couverture chocolate mustn't contain any fat other than cocoa butter, then lecithin as an ingredient breaks the rule.
Lecethin, derived from soy, is usually added in amounts of less than 1%. It has two jobs to perform.
Firstly it does act as an emulsifier. Chocolate is a suspension (not emulsion) of cocoa particles and sugar solids in cocoa buter.
Secondly in quantities of under 1%, it mimics the addition of almost 10% cocoa butter, that is, it increases fluidity.
I'm not a chemist, but I don't believe that lecethin is actually a fat.
Lecethin free chocolate is available, but you will pay for it. I believe Cluizel doesn't use it, and then ther are various higher end makers who don't use it either, but these are "tasting chocolates" with prices well over the $30/kg range