There's a difference
One of the most common questions I get is, "How many minutes on the (insert your roaster here) should I go on these beans to get a good roast?". And it's a question I can never answer. There are so many factors that contribute to a degree of roast that there is almost never a constant. Different voltages (did your son turn on that electric heater in his room? Or did your neighbor flip on their AC?) on your circuit, differences in ambient temperature and humidity, different lots of the same style of bean, and different starting temperatures of the roaster can all cause dramatically different roasts.
In the lab
I did a little experiment here (see the chart above) with the i-Roast 2 , which the chart above demonstrates. I monitored the temperature of the roast with a room temperature i-Roast 2 and then again, right after the first roast (the roaster was a good 30 degrees warmer to start). You can see how dramatic the difference was. The preheated roast finished a good 74 seconds quicker than the cold start roaster and although they both heated up at about the same pace, the preheated roaster ran about 20-50F degrees hotter throughout the roast. The preheated roaster also had a max temperature 20 degrees higher than the cold-start roaster.
This is something to keep in mind when you are trying to duplicate roasts or want to "set it and forget it" with your roaster. Slight differences in temperature can make big differences in roast times. That extra 74 seconds could turn your nice brown beans into dark oily charcoal briquettes in a roaring second crack. |
Learn more about the roasting process with our MoreCoffee! Home Roasting Tutorial!
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