OP, I think some of this talk was in one of my threads. My issue with your experiment is your use of a refractometer and the direct comparison to conversion.
You are measuring wort dissolved organic solids with the refractometer, which will certainly include protein and lipids (albeit in low levels), in addition to sugar. These are additional variables that make your measurement less accurate. Of course, these components exist when measuring brix during any other brew day, but the correlation to conversion is inaccurate. The concentration of some of these components will also be increasing over time during the mash.
However, the use of an iodine based conversion test will provide a more accurate measurement of the actual process of conversion that is occurring over time, instead of including a number of assumptions based on brix. My guess is that actual conversion does occur pretty quick.
Kaiser's experiments suggest mash thickness has a greater impact on conversion efficiency than all the other variables (pH, time, crush). The problem with most of these other experiments is that they are not directly translatable to general brewing practices; they only hold true for the specific experiment, are difficult to replicate, and contain many assumptions and uncontrolled variables.
That said, I very much appreciate your idea. The more people we get to carefully and repeatedly measure aspects of their brew day, the more interesting and appropriate the discussions become.
