Faceplate cleaning for IBTS models

How often are you IBTS owners removing the faceplate to clean ? It was my understanding the IBTS is more tolerant than the original glass fronted IR sensor so needs less poking around. Nothing appears to be amiss with my roasting (charge temp etc) and at the risk of breaking something not broken, I’m tempted to leave alone. The drum doesn’t need cleaning, so does the faceplate really ? I do clean the glass on the door. I don’t roast into third crack if that helps and my roast batches are usually around 600g.

Asking for a friend :wink:

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Hi Stuart-

I agree: “If it ain’t broke, don’t fix it!”

Unlike some of the folks here, I don’t roast huge amounts of coffee (2-3# per week?). But I do track IBTS temp vs. FC (& SC). When IBTS drifts down by about 10F° at FC I clean the IBTS which of course requires removal of the face plate. I tried using Roast Analyzer to help visualize the drift by comparing roasts from different times, but since they place the FC marker on BT instead of IBTS I have a hard time telling for sure. So I end up using the roast profile and jot down numbers. You probably know you will need cotton swabs and alcohol to clean the lens of the IBTS. Odds are good you’ll end up cleaning the rubber view port as well as it’s pretty close quarters.

Be forewarned that you will need to support the face plate once it’s loose from the roaster body. Try to catch the drum as the plate moves forward so it doesn’t drop on the surrounding induction coils & insulation (I think that’s what surrounds the drum). There is very little extra length to the wires and you don’t want to hang the plate on the harness so have the support ready.

In my case, the interior surface of the face plate accumulates a lot of smoke residue which wipes off readily; there is also oily residue under the smoke particles and that takes time to soften & remove. I’ve used dish washing detergent but would have used Simple Green if I had it.

The inside-facing surface of the glass on the hinged door accumulates oily residue (Simple Green again, or just water if you clean it frequently), but that doesn’t require removing the face plate. Cleaning the metal of the door is easier if the face plate is off. Plus you can check the hinge screws are tight while the plate is off (mine weren’t… they’d loosened a little).

I did one serious cleaning after 7+ months of use and it needed it. There is significant oily residue that accumulates if you frequently roast to FC+ or Vienna which I do. The bean temp probe and the surrounding area of the face plate had a lot of that oily residue. I don’t know that cleaning it makes any difference, but I did and there was a lot of gunk. Makes sense as that’s where the beans tumble, surrounding the probe; the movement of the beans in that area is minimal and relatively slow.

While the face plate was off I dragged a rag through the transfer tube to the rear where it would enter the chaff collector. Not sure that did anything but get the loose smoke residue out of the way. In hindsight I should have put more effort into cleaning that tube.

The housing where the exhaust fan is mounted needs cleaning more often, but you can see the contamination each time you empty the chaff collector. In my case the filter screen of the chaff collector needs to be cleaned with a wire brush every 3 or 4 roast sessions. The loose chaff is easy to vacuum out, but the oil sticks to that screen of the chaff filter which increases the pressure-drop across the filter. Again, I roast pretty dark so you may not see the same thing.

Btw, be careful when re-installing the chaff filter. There are 2 grooved edges on the rubber seal-

  • One on the outside edge that is easy to deal with when re-installing the rubber seal.
  • There is also an inner groove where the chaff filter mounts… that one I never noticed till I had ErC 4. I had some new beans that had a lot of chaff. Because of the limited air flow, the collector got so hot it softened the rubber seal and was literally sucking the chaff filter out of the rubber causing it to contact the impeller. Had I seen the groove before and made a proper effort to seat the filter properly I wouldn’t have had the issue of the chaff filter contacting the impeller but I would still have had over heating (iirc, ErC 4).

More than you asked for. Sorry… it was all in one chunk! :slight_smile:

Bruce

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Hey Bruce,

No need to apologise for the verbiage, someone else may (also) find this helpful. I’m aware of the handling precautions on the faceplate as I actually did my upgrade to the IBTS myself. I guess my overall question was is it as necessary (often) as the usual cleanups of the fan and chaff filter (as you noted). I’ll keep an eye on FC, at the moment it’s pretty much 199-200F depending on the bean. I usually just touch SC if at all (usually a City+) so I’m not expecting to find great oily residue.

Thanks for the tip on the transfer tube, I have looked through it but see nothing of great concern at this stage. I use either a weak solution of Cafiza or Sprayz (from the same company) on the filter screen and it comes up a treat. I do take care with the somewhat finicky rubber gasket - getting it seating in the metal cutout as you say is maybe more challenging than it need be.

Stuart

Hi Stuart-

Something puzzling here and maybe it’s as simple as a typo…

You mention consistent FC at 199°-200°F. Is that the IBTS reading? With a just-cleaned IBTS I see FC at close to 400°F. I can tell the IBTS is getting dirty as FC drifts down with each roast from about 398°F to FC at about 390°F. That’s when I clean it before the next session. Did you maybe mean °C? Bean Temp (the thermocouple probe) at FC is around 355°F.

Btw, I find FC is a really subjective marker. At one point as was tagging it at the sound of the very 1st pop which I often missed. I finally accepted that was too inconsistent. Now I wait till I get several pops in a row. I’m in no way convinced I trigger the FC marker properly/consistently!

Bruce

Btw- In versions of RT before 2.5.5-beta, IBTS & BT temps were displayed in C° but labeled as F° if you advanced thru the charts using the arrow icons at the upper right. If you looked at only one chart (the first chart was done correctly) then go back to the Roast History to choose the next chart, that chart displays correctly as F° and is labeled as F°. The current 2.5.5-beta fixes that inconsistency. That may be where the difference is between our measurements of FC.

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You spotted my deliberate mistake Bruce :joy:. I used to be a Fahrenheit HotTopper before switching on the Bullet because you all said the coffee tasted better in Celsius.

I only hit the FC button when I get two or three cracks together…And I’m going by the reading on the roaster display set to IBTS

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Ah yes… the HotTop. Got some good Fahrenheit coffee from that machine. :wink: I still have mine, but my nostalgia doesn’t extend to the waiting time between between a power or fan change and the uncertainty of what might happen in the profile. I love having more power & fan speed than I need!

Bruce

Btw- the first 2 months I had the Bullet I ignored IBTS- Bean Temp was essentially the same as the HotTop so it was familiar. I finally noticed IBTS readings were almost exactly the same as theoretical so I abandoned ship!

This needs an update.

Since Nov 2019 when I wrote this, I realized a 10F° drift in FCs (1Cs) was not nearly soon enough. These days I look at the difference between IBTS and B-Temp at about IBTS = 250°F-260°F for a 550 gm batch. The exact temp doesn’t matter- I’m looking for the largest difference between the 2 readings. When it shrinks by about 10% it’s time.

That difference is very dependent on batch size (I roast almost entirely 550 gm batches)- smaller batches have a larger difference & conversely larger batches have a smaller difference. I keep track of that difference (easily done by looking at roast profiles) and, when the difference shrinks by about 10%, it’s time for me to clean IBTS. Since the difference is very batch-size dependent, a user has to review their own roasts to see what the range is for their roasting habits.

The question might be… “who cares?” Keep in mind that preheat is determined almost exclusively with IBTS (B-Temp is only used to confirm preheat is stable). If IBTS reads low, then the Preheat is higher than you think it is.

Works for me, but as always YMMV.

Bruce

Edit: f/w 606 includes a change to fan speed post-roast which is intended to reduce IR sensor contamination. At first blush this seems to be working for me. I roast pretty dark which seems to require more frequent IBTS cleaning. Also noticed that the chaff filter (the screen cup) isn’t getting as dirty with oil with that higher fan speed (fan → FA).

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How many pounds do you estimate between needing to clean it? I roast less than you. Two pounds per week, maybe, and never to second crack.

Personally, I clean about every 15-20 roasts. About 10kg of medium.

The interval is very dependent on how dark you roast (and the beans). The darker you take the roast the more oil is left behind on the faceplate & exhaust fan. And of course the chaff filter (the screen cup in the chaff collector) will get gummed up from the oils left by a dark roast.

I’m using f/w 606 which includes a change to exhaust fan speed during Preheat to help minimize IBTS contamination. From what I see the 606 beta change works well for that purpose- my IBTS is definitely going longer before needing to be cleaned.

Bruce

Edit- Expanding a little as it relates to the 606 beta f/w… with my darker roasts I’m getting perhaps 15-20 lbs. of greens thru the roaster between IBTS cleanings following the guidelines above. The criteria for cleaning the IBTS is not how many pounds of greens have been roasted but instead the temp difference between IBTS and B-Temp. When that difference diminishes to about 1-2 F° for my 550 gm batches I know it’s time to clean the IBTS.

But that isn’t the criteria for cleaning the face plate and the exhaust fan. I don’t have a temp algorithm for that, so that ends up being about every 2 to 3 weeks. That’s somewhere around 15 batches (almost always 550 gm batch size).

I tend to do a deep clean (i.e. everything according to Sweet Maria’s deep clean guide) every 25 to 30 roasts (avg 1kg batches mostly to med/med-dark), but after every session I also do some basic clean.