IBTS Sensor (Taking off mid roast)

I have been roasting on my bullet for a couple of years now and I have been able to get very consistent roasts when doing the similar profiles over that time period. This past week I am noticing that I am having an issue with the IBTS temp has been taking off mid roast I will get crack earlier on my bean probe than I normally will, but the the IBTS sensor will be recording the proper temp for crack to happen at. So while the bean probe is consistent with what I am use to seeing, it seems like something is happening to make the surface of the coffee much hotter than it normally is. Would this be a fan issue or a sensor issue? I am noticing that there is more charring character, though it is slight at the moment, with the past week of roasting. I am wanting to fix this as soon as possible.

Anyone deal with this issue in the past? Would a recalibration of the fan help? Not thinking its a sensor issue as I am noticing a difference in the coffee once done. It feels like it’s just getting hotter in the roaster.


I would start with removing the faceplate and looking at/cleaning the IBTS lens and fan. I’ve heard once of someone seeing a tiny bean/fragment that found its way inside and was probably throwing off the sensor. If you’re not getting a startup error then likely the fan IS running but wouldn’t hurt to check in the INFO panel if/when it happens again. You should be looking at 14-15K rpm at least.

Good to know. I will be messing with this a little tonight and really trying to figure this out. Thanks for the feed back.

I looked at a few of your roasts but didn’t see anything of note like a sudden transient in IBTS. Sorry… I’m missing what is different. But Stuart’s advice is definitely a good place to start. Maybe a screenshot of the profile that shows it best?


Yeah, I’m not sure why I it hasn’t logged any roasts since last may. I guess it must have logged me out on my software somehow without me noticing. Around 5 minute mark on my roasts is where ibts is starting to drift up and away from the usual course it takes in line with the bean probe. That’s the concern.

If you can get RT3 to log-in you could try the “Re-Sync” button at the top of the Roast History page… that should update the server.

I’ll leave something for @derrick in case he misses this note. He probably can figure out why the server isn’t updating.


Looking at your file last year in RW, I have noticed the delta between IBTS and BT is about 17c at yellowing. My experience, with a batch of 500g green bean, it should be around 30c ~ 40c. If the delta is below 20c that is a strong signal that I need my IBTS sensor cleaned ASAP. Hope that helps.

1 Like

Hello @ec8740,

Are you using the RoasTime 3.4.0? I can confirm that I have seen this issue with another user using RoasTime. However, it turned out that this is/was not an issue with the RoasTime app itself but rather an issue with their computer’s settings. Would it be possible to try RoasTime on another computer? I think your case is probably similar to the one I previously mentioned.

Best regards,

If you try another laptop and RoasTime does indeed work, then that means that there is some setting on your computer that’s blocking access to RoasTime to allow it to upload its data. Your roasts data are still stored locally. If you would like to move to a computer in which RoasTime is uploading/downloading correctly, you can follow these instructions (for pc):

Here’s a list of the steps they can take:

  1. Visit this folder (if they are on a PC): C:\Users\<name>\AppData/Roaming/roast-time
  2. Go into the roasts folder and copy all the roasts files. These are JSON files with the file extension: .json
  3. Connect to your new computer and then visit the same location on your new computer (C:\Users\<name>\AppData/Roaming/roast-time and paste the roasts files in this new computer’s roast-time/roasts folder.
  4. Force a manual re-sync.
  5. I think it’s safer to just copy the data in the roasts folder rather than the whole roastime folder.

Additionally, I think you should be able to copy the beans and recipes folder as well.

1 Like