Higher IR temps


Hi everyone,
Over the past few sessions I noticed the IR bean temperatures are about 5 deg C higher at FC than previous. The regular bean probe temperatures are same. I have V2 and could only find this problem affecting V1 machines with dirty IR sensor windows. Anyone have any insight as to what the problem might be? Thanks in advance!



If you had a piece of chaff partially blocking the view port for the IBTS and it got blown/knocked away, that would explain a sudden jump in emission level from the drum/beans. Beyond that I’ve only seen gradual drop in IBTS at FC explained as you said by a dirty lens on the IBTS.



Hi Bruce,
Thanks a lot I appreciate your suggestion. I took the face place off, cleaned the area and will see how that works. Thanks again.



Did you use a cotton swab with alcohol to clean the IBTS lens while you were at it? From your description I doubt it would change readings but it might dislodge something near the sensor in the process.



I took your suggestion and went back in with a soaked swab. The glass certainly looks squeaky clean. I’ll have to fire up the roaster soon and see how it goes. Thanks again for your input, I’ll let you know how it turned out.




This can be one of those ‘looks can be deceiving’ sort of things. I’ve almost (!) always had the swab come out clean yet I can see a distinct shift upward in Drum Temp. Not very satisfying to clean the lens and not find anything, but it can make a difference. The point is you have to go by Drum Temp vs. Bean Temp data.


ps- I’m wondering if the contaminant is maybe white causing it to not show up against the background of a cotton swab.


Well I attempted one roast and there was no change. I did see someone on the FB group had the same issue I have. Interestingly it seems that a dirty ibts glass would give a lower temp reading than actual not a higher.


I stayed on track for my first 3 replies but by the 4th I was addressing my own issue with IBTS which is a gradual decay in displayed IBTS temp, i.e. about cleaning the IBTS lens and expecting the displayed temp to rise. That’s not what you’re addressing.

Looking back I think my first guess was better- that a flake of something blew away from the IR view path causing the jump in IR reading.

I guess the only appropriate question is how does the coffee taste? Is the roast coming out as you expect?



Hey Bruce,
Well, I’ve cleaned the IR glass twice and no change… After taking into account the new temperatures of FC etc… there isn’t much change in how things taste which is good I but still a little annoying since it had been so consistent up till now.

I contacted Aillio and they suggested taking apart the front panel and making sure there was no space between the housing and lens hood which I did. After getting a good look at the intricacies of how the IBTS is held in place it seems like they need a more secure way to do it. I can see how it could get pulled out of place rather easily. I have yet to see if my latest attempt has solved the issue. Anyways… once again I appreciate your input.



Possibly not what you want to hear, but it’s sounding like an issue that resolved itself when the displayed IBTS temp jumped up. Especially in light of FC being consistent with Bean temp (thermocouple). I’ll venture you need to treat data today as correct and what you saw early on as the aberration.

Btw, you might want to experiment with the Roast Analyzer tool in R.W. It does a credible job showing roast-to-roast variations in FC using Bean temp. The IBTS curve is also displayed so you can compare how BT varies vs. IBTS.



Hi Bruce,
Looks like I missed your last post. Well I decided to order a new probe and the new one is reading temperatures pretty much back to where they were before I noticed the jump in temps. Until I replaced the old one ( 2-3 weeks a go) the probe the temperatures continued to read higher and higher so something clearly wasn’t right with it. Anyways glad to have the situation resolved. Thanks again for your input.



Glad you got it resolved. I’ve not had the faceplate apart enough to have access to the t/c probe… must have been a challenge!



Yeah I had lost confidence in the temperatures and wasn’t sure what to expect roast to roast so yes glad to have the situation resolved. I’m not technologically or mechanically inclined but did not find removing the faceplate too challenging mainly because I took a lot of pictures as Aillio suggested along the way. I was rather shocked though that it the thing started up again each time.