Back to the old days when we used to suck seeds of ripe cacao fruit to remove its mucilage. For all we knew it is the easiest way to do it. Some folks are forcefully scrubbing it with sand and achieving very nice results. A very clean looking cacao beans when dried. Otherwise, intact mucilage will cause clumping of beans and some ugly dark brown looking spots.
Later, I discovered, the mucilage need not be removed. The fermentation process is doing a good job of breaking it down. Plus, removing too much bitterness and creating flavor precursors.
Usually non fermented beans has typical brown color. It taste very bitter. On the other hand, fermented has a shade of black and covered with white looking mold growth. The latter may smell slightly acidic due to inclusion of partially fermented beans. While the latter may smell medium to strongly acidic. A visiting fried lately said my newly delivered cacao beans tasted like macadamia nut. No one has ever said the thing to my old raw mats.
Based on experience alone, the strong astringent flavor of the ordinary retains after roasting. The fermented has a an acidic flavor which fades after. The remaining sourness is further removed during grinding and conching process.
I have been working with cacao beans for years but it was only recently I got a very deep interest to it. I was using erratic pan roasting before but later switched to oven roasting to improve quality. I still have very little knowledge to share and so much to learn.