I think the 630 micron sieve is removing too much from the coffee for 2.5 min pourover to produce a flavorful brew. I would try a full-immersion style brew where you can more easily extend the dwell time, like French Press or Abid Clever. Or find a finer sieve in the 100-200 micron range.
Also, what kind of coffee are you using and how was it roasted?
Thanks for the reply. The screen is certainly removing a lot of material. It is an interesting comparison to the distribution graphs at the start of the post and it shows that the cheap grinders have huge partical distributions and no tight peaks. I also have a 24 mesh screen which is about 800 microns. So, I know my particals are somewhere between 630-800 microns. Based on the chart on page 37 http://www.mpechicago.com/coffee/images/uploads/pdfs/SCAA_2009.pdf
the brew time is 3-5 min for particles in this range. I will try a longer dwell time (when I get some fresh beans) as you suggest and see how it changes. The beans are from intelligentsia.
My preliminary experiment was interesting to show just how important the GRINDER is in producing a cup of coffee because the distributions of particles are very very different from a cheap grinder to expensive.
Hopefully the longer dwell time/fresher beans brings me closer to the store brewed taste. The only thing that still doesnt make sense is that the refratometer reading (calibrated with distilled water) showed that the cup should have tasted strong/flavorful based on the amont of dissolved solids.