We start with only the highest grade possible of raw coffee beans. To find the best beans, we evaluate the following: bean size, bean color, uniformity of size and color, occurrence of any "defects", and most importantly the flavor of the roasted coffee when brewed.
Defects found in raw coffee beans can be anything from unripened beans, to broken or discolored beans, to stones, twigs, or any foreign matter. The greater the number of defects found in a random sample of a lot of coffee, the lower the grade that lot is assigned. Higher quality coffee is more carefully sorted to remove all of the defects. This additional sorting takes more time, and as we all know, time is money, which is why higher grade coffee costs more.
Coffee from a single country is known as an Origin or Varietal. Coffee from any single origin will be available in several different grades of quality, we choose only the best beans which may cost a little more but it produces a better cup of coffee.