Classification should be more than colour based since most roasters don't even use standardized colour scales. I agree that solubility should count but at the same time I have no problems extracting very light filter roasts, especially those coming from a Loring. Ambiguous roast descriptions like "we roast to preserve the origin caracter", can be very misleading since it leaves everything up to the roaster. I've had the same coffee, in 2 consecutive years, from the same roaster that was delightfully light one year and disapointgly medium dark the next. This kind of situation makes recommendations quite a challenge.