points taken. gives me a lot to think about. really, thank you peter. here is what jay wrote on coffeetec, related to cast iron and Probat 12 kg vs. Joper 15 kg:
"Roasting technology is actually returning to the most friendly contact material considering expansion stability, bean friendliness and a warm moist heat that is gentle against the raw coffee . . . Cast Iron. There are other very good roasters out there - but Cast is different and probably desirable. Both of these roasters are the same in function and while I have been a part of the Probat family for years . . . the Joper is catching my attention as it is doing some nice things that may make it a Best Buy choice. While Probat needs to be congratulated for returning to their cast iron roots, the Joper Foundry has simply created a little thicker and more technically friendly configuration on bearing and gear drive motor mounting that allows it to run cooler and more quiet. They look alike and take up the same footprint and finally the Probat has put it's chaff collection outside too (long needed) . . . both have adopted the double-wall-drum method to allow an air space between the bean contact and the flame contact - this is fantastic on both machines and long, long overdue. Joper has a low-nox burner with more range in control. Also Joper has a timer in the dashboard - nice addition. While you can't lose with either . . . I am well pleased and you will be too, with the Joper and when I really saw them side by side . . . I am giving Joper a slight edge over the Probat. Remember too, the Joper's drum size allows more production over the hour."
i found the above quite interesting, as jay gives the nod to Joper. bottom line, i understand that the best roasted beans come from a roast person/master who understands his/her equipment well, and with great intentionality, brings out the maximum flavor of the beans. i've seen it so many times written here and elsewhere... the most important component affecting a quality roast is on the human side of the equation, not the brand of the roaster.
sidebar: as i type this, i am enjoying a very delicious cup of guat drip brew from a roast 4 days ago, of which i thought i botched (pulled too early after 1C). by the time i could get back to tossing the beans back and forth to get them cooled down enough to stop the roast, and after burning my right thumb twice just trying to get the beans dumped out of my dog-gone roaster, they actually entered 2C. after they cooled and sat for 4 days, i have a little bit of heaven to enjoy. best roast yet on my low-tech weber set-up! now, if i could just repeat it. hah!