Dave's right. It really is that simple. I've watched in awe as our winemaker took out 4 bottles of different single grape wines, various sized graduated cylinders, a wine glass, and a spit bucket. He then went to town blending. Now, of course he knows all the varietals, their characteristics, and what he is aiming for so he knows which will be the base wine, and then what the other three will do and about how much to add.