Steve: where do you "shoot" the HG relative to your bean probe? Mine is shooting directly at the bean probe, which is placed around 15mm from the bottom of the pan, so under the bean mass, but still affected by the HG.

Getting thermocouples to give a readout via Artisan is done via attaching the probes to a compatible device that plugs into your computer's USB port. Then you can watch the temps and profile curves developing in real time. Also my Corretto roaster has a soup can I cover with a steaming cup so I can lift the cup as a baffle. Air also circulates out through venting holes in the lid.

My heat gun is positioned through a hole cut the bottom left of the baking tray cover. The thermocouples are effectively top right as far away from the gun as possible. The gun points directly down and both probes are not in line with the gun.

These connect to a laptop via Artisan software. Works really well as you can see the curve and ROR in real time but I do get occasionally the odd spikes in readings due to a communication glitch between the two. Doesn't affect the graph once the roast is done though.

Again with the caveat that I don't use a heat gun...I see several problems. First, that charge temp looks way too high, if it is anywhere near accurate for BT (probably not). Second, there appears to be insufficient BT drop, which indicates a probe placement problem; it should go way down on drop. Then, you have nearly no upward motion through the roast, as the curve is way to flat (not sure if this is real or due to probe...probably both. Finally, right after 1C it looks like a stalled roast, as the temperature is going down somewhat.

In my drum, I charge at around 200 C. BT drops like a stone, turns back up at about 1:30, then yellow ends (~150 C) at about 4 to 4:30. From there on, I follow a rising curve right through to drop at about 200 (my probes read a little low so this might be a bit higher...it's all relative). The point is, there is always upward temperature development on the BT right through to the end, even though the rate of rise drops slowly through the middle part of the roast.

In my air roaster, which might be closer to heat gun roasting, I start the roast without much warm-up (no point in a small air roaster) and the heat on low for a couple of minutes, then go to high until the beans go through yellow, which would be about 150 C. I turn the heat to medium at this point, then back to high after 1C has just started, as I like to drop just after 2C just starts for most of my espresso (leaving on medium would take too long after 1C and yield a flat roast).

Stevebcoffee wrote:My heat gun is positioned through a hole cut the bottom left of the baking tray cover. The thermocouples are effectively top right as far away from the gun as possible. The gun points directly down and both probes are not in line with the gun.

These connect to a laptop via Artisan software. Works really well as you can see the curve and ROR in real time but I do get occasionally the odd spikes in readings due to a communication glitch between the two. Doesn't affect the graph once the roast is done though.

The Heatsnob software shows me an instantaneous readout. I roasted 3 batches this morning. I placed the Heatgun opposite of the heat probe which makes the temperature much less affected by a slight change in HG movement. I do not think my probe is low enough in the bean mass to give me a good bean temp. Today I was hitting FC at 180c, compared to 208c when the HG is pointed at the TC.

the roast curves are only relative to each machine, I think...but should help me replicate a roast that I like...