I roasted 3x600g batches of coffee today. The first roasts seemed fine but on my third roast, the bullet started smoking from the side holes that you can see on the chaff chamber. This has not happened before. I was instantly alarmed as well as confused.
I was in the recipe mode and this happened near the very end of the roast and the roast end-alert popped up. The beans come out smoking and are oily, very burnt. The recipe I was using had the end temp of 217 degrees celsius, and according to RoasTime, the end temp (IBTS) was 219. This cannot be the actual temperature. I’ve used this recipe two weeks ago and this absolutely wasn’t the outcome.
I empty the chaff chamber either after ending a roasting session, or after 2-3kg roasted. I also regularly clean the filter inside the chamber. I haven’t touched the IBTS sensor, however. I have maintained my bullet to my best understanding keeping it clean and safe, as well as followed the manual. After emptying the chaff chamber after this session I notice that the back of the machine (inside) is oily and I can actually see dark coffee liquid/oil slightly dripping. Before this roasting session I had taken the chaff chamber off to make sure it’s ok to roast with and it wasn’t particularly dirty and didn’t seem off
As I roast indoors, the smoke alarm went off, which hasn’t ever happened before.
My Bullet also ended up making some weird noise after finishing the roast, which I haven’t heard before. I can’t describe it, but I believe it came from the back end of the machine. There were no error codes.
I don’t really know where to go from here. I will start off by cleaning the parts I am familiar with, but if anybody has any suggestions please let me know.
I apologize that this message is quite poorly organised. I tried to include everything that is, or could be, relevant. I will happily share more or take photos. I appreciate your help. Thank you.
I looked at your last few roasts and the last roast showed that the Bean Temp (BT)was at 450C while the IBTS was reporting 220C at over 10 minutes. Most of your roasts are in the 8 minute range.
Cleaning the IBTS sensor is commonly done by many of us here. How often we clean the sensor is largely determined by how dark we roast.
Cleaning the IBTS sensor, requires removing the faceplate and using a cue tip with alcohol. You might not see any dirt or oil on the cue tip, but keep cleaning. It doesn’t take much oil/dust to cause bad readings.
I ended up cleaning the sensor as well as giving the machine a deep clean, but I don’t need to be roasting now to test whether or not it will work. So it will have to wait the until next weekend. It is stressful when the Bullet was a huge investment for me.
The last roast (the third roast of the day which failed miserably) was actually meant to be higher in temperature. The earlier two were of different origin and the end temp was 208. For this one it was 217. But yeah it most definitely was far more than that.
Is IBTS and BT crossing always a sign of something being wrong?
Also, I would like to add that I got the ambient temperature error code about two weeks ago. It went away after so I did not think much of it. Could this have already been a sign that something is off?
Thank you so much for helping. I apologize for the questions, especially if they’re silly. I am still not very experienced.
The short answer is no, Drum Temp (IBTS) and Bean Temp (Bean Probe) crossing at the end of roast is not always a bad thing. In a 1kg batch size, you would see the cross happening. This is because the Bean Probe is more dependent on the batch size; the bigger the batch size (1kg max), the closer to real-time readings it’ll get.
Your Bullet behaved strangely; it was certainly working fine before the last roast, and it would be very unlikely to get dirty and inaccurate within a couple of minutes.
In addition to checking the IBTS Lens, we would suggest taking a look at the IBTS Module. Here’s a guide to installing the IBTS Module:
Please follow the guide to check if your IBTS Module is misaligned.
I have now cleaned the IBTS sensor, but I did not check if the module is misaligned (yet). I am also waiting for the support’s reply on this and some other issues that appeared [which are the following, but you can skip this].
(1. Temperature not rising with an older, found to be good, recipe.
2. The beans pushing through the glass door on the front plate during a roast, and beans getting stuck inbetween the roasting chamber and the door.)
If it was the case that the IBTS module were misaligned, could you explain to me what could have been the cause?
I can’t help you much with the rest, but after cleaning the sensor and putting back the faceplate, you must also put the drum in place. That’s why you’re having these issues. Here’s a link…
Oh ok that’s my bad, thank you! @da_kevin if you could help in that case that would be great. I will quote my issues here from above:
“1. Temperature not rising with an older, found to be good, recipe.
2. The beans pushing through the glass door on the front plate during a roast, and beans getting stuck inbetween the roasting chamber and the door.”
Now that I know I need to put the drum in place after putting the faceplate back, that might solve the second problem. This is what I am going to do right now, and may try roasting after.
Edit: I have now tried to push back the drum to the correct position. I am unsure whether it did anything but I did as instructed.
I tried to roast afterwards. I held the door closed the whole roast since someone had also suggested that in the post shared above, so I can’t be sure whether that problem is fixed.
During this roast the issue with temperature rising still persists.
I have yet to check the IBTS module and its positioning. Since I’m not quite familiar with this sort of thing, how careful do I need to be while doing this? And do I need to disassemble the module completely like shown in the guide video you shared, Kevin?
I apologize that this post has become quite unorganised, but in this comment there should be everything that’s relevant. I will provide more information if anyone has questions.
Could you share the reference roast (recipe) and the resulting roast with me? I’ll take a look for you.
This happens when the clearance between the Drum and the Front Plate is too big. Have you recently removed the Drum for cleaning? You might need to check if the Shims (metal washers) are missing or if the Bearing is misaligned.
We would suggest disassembling the Front Plate for examination since you’ll need to look around the IBTS Module to ensure there is no gap. For your information, the IBTS Module can be misaligned during cleaning, when people poke the IBTS Lens with too much force.
If you’re really not sure what to do, please contact [email protected]. We’ll find a way to look at the IBTS Module with you.
I was suggested to remove the front plate to clean the IBTS sensor. Somebody afterwards told me that after removing the front plate you also have to put the drum back in place. I removed the chaff collector and tried to push the pulley but I wasn’t able to notice it moving. I will be able to test whether it worked or not next weekend.
I will double check the bearing and the shims, but to me the front looks exactly like it used to be with everything looking to be in place.
I’m going to try to do this once I’m back home and if in doubt I will be in touch with the support.
