Our government - not always known for its romantic tendencies - lovingly calls couverture "industrial chocolate," and refuses to define it in its all-important chocolate Standard of Identity list. "This standard is an unnecessary category," it bluntly says. We think those are clear grounds for a congressional hearing*.
Couverture is a candy-maker’s term for high-quality chocolate. They also refer to it as fine chocolate.
The blend of cocoa beans used to produce couverture must include at least 40% "high quality" beans, which make up less than 10% of each year's harvest. It also has a high percentage of cocoa butter (generally 31% to 38%), so that it flows easily when melted. This makes it ideal for molding and coating candies and other confections (the word couverture comes from the French "to cover"). Couverture includes only chocolate liquor, added cocoa butter, sugar, vanilla, and lecithin, an emulsifier most often derived from soybeans.
The number everyone is fixated on with chocolate these days - the percentage of chocolate liquor it contains - has no bearing on whether chocolate is classified as couverture or not. We have seen couverture with a chocolate liquor content as low as 36%, ranging up to 80%, which is very bitter. It can be dark, bittersweet, semisweet, milk, or white (although, as mentioned elsewhere, white chocolate contains no chocolate liquor).
When it’s tempered correctly (melted and maintained at a certain temperature) couverture will harden with a beautiful glossy shine.
It is possible to purchase couverture in specialty shops, chocolate shops, and perhaps in very well-stocked, upscale supermarkets. (We, occasionally being a little cynical, are not convinced that everything labeled couverture is actually couverture, but hope it is of reasonably high quality). People in some parts of the country are going to have to look online to find it.
If a recipe just calls for couverture, it is a suggestion that you use the best-quality dark chocolate you can find and/or justify paying for in the recipe.
*Yes, we realize how much congressional hearings generally accomplish. We're not stupid, you know....