Only one way to find out. We need empirical data. Fire that baby up and roast a couple dozen batches. Let us know what happens.
Some people might say that you should stop using a Sears electric weed whacker when it starts to smoke, but I know from experience that it will keep on whacking weeds up to (and actually about 15 seconds past) the time it bursts into flames. No way I would know that if I followed the manual.
If you find yourself with too much coffee after running the experiment, feel free to send it to me. I’ll do my bit to help.
I’ll do the control side of the experiment. Already have, by the book. About two years, hundreds of roasts, and it’s showing it’s are but still works just fine. With a little babying.
But here you go; mmmcoffee
About $13/lb shipped for the best coffee you ever tasted.
Downside, you’ll stay from Starbucks. But that’s an upside, isn’t it?
There are competing factors at work here. The stresses of heating up and cooling down come primarily from the expansion of the components when they’re heated and the contraction when they’re cooled. A temperature difference of 230-330 F isn’t enormous, but over time it can cause problems, particularly because it’s made of different materials, which will most likely expand/contract at different rates.
The other factor is mostly associated with the plastic. If you heat plastic or any other polymer up, the rate at which the polymer bond break increases, and can increase pretty dramatically. Whatever plastic is used for the iRoast will be able to withstand the design temperatures for a reasonable lifetime, but eventually, it will lose some of its characteristics as the plastic breaks down because of the heat. If the plastic behaves like most plastics, the vast majority of degradation will occur at the highest temperature. So the big factor is the total time at which it stays at the peak roasting temperature. If you leave it on for, say 20 minutes, to roast two batches, and the time at peak temperature using the cool/heat cycle is only 16 minutes (for 2 batches), then you’ve kept the roaster at peak temperature an extra 4 minutes.
Whether this extra 4 minutes of peak temperature does more damage than the cycling is impossible to say. I’d say that the roaster is probably designed for a lifetime that takes into account a fair amount of “off-spec” operation, so it’s probably not going to crap out on you, at least before the warranty runs out.
The other issue that can come into play is the outside temperature of the roaster. I’d expect that the heating system is tied to a thermostat that maintains the temperature on the inside at the desired point. If the roaster isn’t designed to handle much more time than the 8 minutes at peak temperature, you might start getting into a situation where the outside of the roaster begins to heat up considerably, causing a serious safety issue. All that heat has to go somewhere, and if it’s left on continuously, then you start working toward thermal equilibrium between the inside temperature and some steady-state outside temperature. That steady-state outside temperature will depend upon how much air is flowing around the outside, and how well the outside radiates heat to the surroundings. If it stays on long enough, that could be pretty darned hot, to use graphic engineering terminology.
Thank you, Public Animal No. 9, that’s exactly what I was asking.
I’ll continue to use it as directed in appreciation of it’s good service and your well thought out analysis.
