Awesome Mark thanks for the response! To continue.
Given assertion 1, then I don’t really see the point in competitions taking TDS measurements.
My own experience has been that agitation in the beginning is a “good” thing, agitation at the end is “bad”. Anytime I have lifted the dripper with water remaining, has always been a sub-optimal experience. For anyone who has a Sette grinder, you know what I’m talking about.
My own non-scientific “feely” argument has been that toward the end, the coffee grinds have been fully penetrated and expanded by the water. So any agitation, has a stronger impact on extraction meaning that the timing “window” for the optimal brew becomes much shorter with agitation at that time.
Ilustration by extreme, would be to heavily agitate the entire brew continuously, with same TDS as above experiment and determine “quality” of the varying cups. While certainly subjective, might provide some hints of agitation extracting the “better” at the right time and possibly minimizing the “bad”.
Of course, without the water fully penetrating and expanding the grinds, efficiency of extraction likely affected. Flip side, agitation might accelerate water penetration and expansion so that further slow and controlled flow rate efficiency is maximized. For Good or Bad… dunno.
For me, my brews have greatly improved by stronger pours initially and low force pours at the end. What doesn’t work as well, is maintaining a constant rate of pour for the different pulses. This method assumes a certain inherent “goodness” around uniformity, which while helpful for hitting the mark for consistency(a good cafe goal), is a meaningless goal for the home if the opportunity for the “perfect” cup is sacrificed for cafe efficiency goals.
Also, with the Barista Hustle subscription, I am now exposed to coffee that can really push extractions with great results so the rules for those types are different for the usual (but Great!) coffee roasters I have access to in SoCal.