Machine and method for preparing beverages based on coffee beans

method for preparing coffee-based beverages starting from coffee beans by means of a machine having a hopper configured to contain said coffee beans, a grinding member associated with said hopper to grind said coffee beans and obtain a coffee powder, brewing means configured to subject said coffee powder to brewing and hydraulic means configured to supply water to said brewing means, wherein said method comprises an identification step in which one or more actual characteristics of said coffee beans are automatically identified by means of identification means, and one or more functioning parameters for at least one of either said grinding member, said brewing means or said hydraulic means are automatically associated with said one or more actual characteristics, characterized in that wherein said identification step provides to acquire at least two images of said beans contained in said hopper, illuminated on each occasion by one of at least two lighting elements configured to emit respective light beams that have different wavelengths from each other, and to process said at least two images in order to identify said one or more actual characteristics.