A distinguishing characteristic are the sediments that settle to bottom. Sediments vary from very fine to rough depending on grinding machine used my the manufacturer. Very little fine to no sediments at all is indicative of highly processed product. Perhaps not healthy.
Oil spots are visible on surface. Those oils are cocoa butter. The absence of emulsifying agent, such as lecithin, never prevent rising of oil to top.
The two above mentioned characteristics if unwanted could be remedied by filtering after cooking, adding milk and blending in waring blendor. Opting for a commercially available chocolate bars is an alternative.
It is similar to wine to some extent. The flavor further develops during storage. In choosing tabliya for tsokolate, we prefer those that were made at least one month ago.
Usually, white spots on surface are not molds. They are called fat blooms. Them appearing never affects flavor in anyway. They are not good looking though.
It is also prone to mold growth. I am not sure about the specific conditions which would encourage such during storage. It never occurred on our stock while on hold. However, one customer did ask for replacement. The product he returned smelled bad and had evident of molds.
Old folks recommend stirring the mildly boiling tabliya solution with a batirol. Many think it is more delectable when prepared that way. I don’t think it is different against mixing in electric blender after cooking.
Many are drinking plain tsokolate without sugar. I couldn’t understand why they are able to drink it sugarless. Maybe they think the same way to me. I drink strong black coffee without any drop of sugar.