After I tested the Colombian and Guatemalan, I wondered if I dare try a three-blender. What would it be like if I added Sumatra to the mix? After several attempts over a period of two weeks, I have found the correct blending ratio and degree of roast for each one. Roast the Colombian to a Full City, just before the 2nd crack. I then roast the Sumatra to a Full City. The Guatemalan I take to a light Vienna, but just barely. I hear one tiny snap of the second crack and I hit the cool down. I let these beans sit in a sealed container for 24 hours. Now you have a coffee that is bright and fruity, with a slight earthy taste, and a sweet and clean well-balanced cup. There are so many subtle differences in this blend that it is difficult to pass up!