IBTS... To clean or not to clean? That is the question

For Bullets with the new IBTS, is there an official recommendation as to cleaning the inside face (IBTS) of the Bullet. The IBTS is said to be self cleaning. On older machines, there is a recommendation to clean the inside every 10kg roasts. I assume that since the IBTS is self cleaning that the every 10kg cleaning recommendation no longer applies.

Is there an official recommendation. It is not clear to me in the updated manual 2.8 .

My new IBTS is still receiving coffee oil build-up and I need to clean it every 25 lbs (10-11 kg). I’m curious to see if anyone else’s new IBTS is seeing coffee oil build up?

If you see that your FC temperatures are suddenly different then you should inspect the sensor and clean it with a cotton bud and a drop of alcohol. We are investigating why some IBTSs still have a little residue on them. One of the theories is that dust while filling the hopper travels down the side and is being sucked into the micro fan and then onto the sensor.

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I also struggle with my IBTS. For the first 100kg it worked fine, but since 2 months or so I need to clean it at least every 10kg since IBTS temp drop by about 2°C.
Any help would be well appreciated.

I’ve seen the same thing. My current favorite suspicion is that we may be seeing some aging in the IR sensor as well as some accumulation of roasting ‘stuff’. ‘Stuff’ means I have never seen anything on the cotton swab after cleaning, yet cleaning makes a difference in IR levels during the roast. ‘Aging’ means that no amount of cleaning has restored the original values I saw before I realized there was a need for cleaning.

Recently I noticed that batch size changes the difference between BT & IBTS levels: a larger batch brings IBTS closer to BT values, especially at the end of the roast. Unfortunately I can’t tell if IBTS is lower or if BT is higher. This isn’t a change in IBTS behavior- it’s just that I always roast 550 gm batches till the day I tried one 800 gm batch and one 1 kg batch. The difference between IBTS vs BT was noticeably smaller. And again, there’s no clear way to tell if one or both of the sensors is different.

Bruce

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It makes sense that BT is higher for larger batch sizes, where the thermocouple is more fully immersed in the bean mass. I’ve been concerned about the other end of this issue: is BT temperature unreliably low for small batch sizes like 325g?

I wonder about that as well. I started using the Bullet with 300 gm loads but finally thought “why am I doing a small batch like this? limited loads was a HotTop thing”. I can’t answer your question but as I think back I seem to recall having trouble correlating 300 gm vs. 550 gm roast profiles. I’ll see what a little digging turns up but I didn’t keep very good notes 2 years ago.

Bruce