The various devices used to roast coffee beans provide heat to roast the beans in different ways. The three methods are convection, conduction, and radiation. Listed in the chart below are some of the differences in the effect of these devices.
There are at least three ways to determine the differences in the heat transfer process in coffee roasting.
WAG, EG, and SP.
WAG, aka wild ass guess, is perhaps the least reliable but gives one at least a starting point to understand the heat transfer process.
EG, aka educated guessium, is an assessment of a WAG after having thought at length about it and researching the internet extensively until one’s eyes will not focus any longer to find an answer. SP, aka scientific process, is the most reliable, but it is a little too time consuming and costly in order to collect enough data to be accepted as a valid presumption.
The chart below is EG certified.