How do I get RoasTime to show the exhaust temp curve? I noted my last couple roasts doesn’t show a value for exhaust temp, is something wrong?
I’ve seen some folks who have a curve for exhaust temp plotted on their roasts.
The exhaust temp is not part of the Bullet. However, you can buy a bean probe from Aillio and modify it yourself.
whats the benefit/advantage in the cup of knowing the exhaust temp?
I don’t know. I think the IBTS provides enough info. People coming from gas roasters are used to the exhaust air, but we at Aillio don’t use it.
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Fair point. I was asking because as I ramp up on the software/hardware I’m comparing what I’m seeing to what others are sharing and it was a noticeable difference.
I come from a sonofresco that has exactly one curve you can watch, exhaust temp. That’s it, no bean temp, not drum temp, none of that. You have to do the whole roast with exhaust temp alone.
So I know it can be done, and I’m hoping to understand more of what to watch and when as I get used to the machine 
@joshua.armour: I’m also a Sonofresco “immigrant.”
On the Sonofrescos, you’re actually getting an estimate of bean temp, based on an exhaust temp and an algorithm (a.k.a., a bunch of assumptions). So the single curve you’re used to seeing is similar to the IBTS curve. Actually, I think they tried to make it similar to a “normal” bean temp probe, so their curve would be somewhat directly comparable to what folks are used to in other roasters.
Note that the Sonofresco temps are normally around 175-185C for first crack and about 195-205C for second crack, while propane burns at 2800C, with likely exhaust temps around 500-600C. Clearly, there’s no way those Sonofresco temps are simple exhaust temps.
Just FYI, so we all know what we’re looking at.
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Yep, I suppose they are doing some sort of math to make the number look normal. I’m simply referring to the physical probe which is in the exhaust hood, and it is the only thing measuring temperature thus the term exhaust temperature. Should probably call it exhaust probe instead.
It’s nice that the aillio has more than an exhaust probe isn’t it?
I have an older model without IBTS, but I plan to upgrade, and when I do, can I use the old bean probe for ET?
For now the Bullet still needs the bean probe to operate normally – it’s fundamental for triggering the charge command, for instance. And if the Bullet doesn’t detect the probe it will error. It would require some Firmware changes, then, but I think in theory it could be done. Would probably make more sense to just get another bean probe and double up tho. Not sure what the Lillie brothers might think.
Yes, I know data can be lovely but I’m not sure what exhaust temp would bring to the table here - we already have bean temp from two sources and I can’t see how exhaust temp could be reverse engineered to different types/sizes of bean in the drum. It’s a bit like being blindfolded and asked to drive a car with a sighted person in the passenger seat giving directions. It could be done but WHY?
I have an ET probe. I don’t think it provides useful information. In the winter its always higher than the BT, in the summer its lower…so not really useful.
So at least it tells you the season - should you be in doubt…
Jokes aside: I were probably the first to implement the ET probe, and frankly I did it in order to investigate what this parameter could add to the roasting equation. However, I was not able to pick anything important out of it. But surely it might contain some valuable info that is somewhat masked by the season and maybe probe placement in the exhaust stream
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