A way of making the sugar in the coffee bean caramelize so that the coffee tastes stronger in a weak brew. This way you can make coffee with less beans or beans of a lesser quality. A trick used in the fast food industry and by Starbucks. If you drink it pure you will taste a burned, charred flavor, but if you mix it with steamed milk and add lots of corn syrup it will taste better and stronger and thus fooling the client letting him/her believe he/she is drinking a better coffee than he/she actually is.
Gourmet coffee doesn't need overburned coffee beans.