IBTS graph all over the place for back to back roasts of the same bean

[shoestring]

Hi,

i have been having ths issue since i started doing back to back roasts.
a syou can see in the graphs attached. the roast time and quality seems to be the same but, the profile curves go mental as i continue the back to back roasts. Also all my curves seem very noisy to me… is this normal?

i have no idea why this is happening

thanks

[thewildcup]

I see your charge weight is 1kg – could be a stuck bean. They can get wedged against the BT probe. When’s the last time you cleaned the IBTS sensor? Once again, with full capacity load could be dust or even a bean jammed up in there somewhere.

[jeffras.cce1a9]

One observation, all three batches hit first crack between 9:03 and 9:12, ended at 205 to 206 IBTS, and lost 15.2 to 15.3%. That is about as consistent as back-to-back 1kg batches get, so I would trust those over the RoR lines.

The IBTS and probe lines themselves look smooth in all three. The noise lives in the two RoR lines, and RoR is a rate of change, so it magnifies tiny wobbles in the reading. The orange I-RoR swings do grow, so something is shifting, but my hunch is it is the readout more than the roast, possibly a firmware quirk in how the Bullet is sampling or smoothing that channel rather than anything happening in the drum. The cup is the real test, if all three taste the same side by side, I would investigate the firmware and sensor hardware.

[braca19452f9m]

@jeffras.cce1a9

The IBTS and probe lines themselves look smooth in all three.

No. The jumps from the IBTS curve are reflected on the RoR curve. It’s just that you see them differently because they are measured differently.

@shoestring

i have no idea why this is happening

This is the R2 and I’m not sure what other differences there might be other than IBTS calibration.

IBTS sensor reading too low after cleaning

Hi, just received an answer from Aillio support: Adjust IBTS Calibration (If readings remain low after cleaning) If the lens is completely clean but First Crack still lands low (around 188°C instead of ~200°C), you can easily bring the readings back in line using the machine’s menu: On the Bullet, open the menu and scroll down to IBTS Calibration (Calibrate Val). This setting lets you adjust the reading up or down by up to 2.5% (a value of 25 is maximum). Since your reading is low, increase …

That being said, let me link my other post as I did find the swings can get wild when the appropriate amount of heat is absent. Barring any huge differences between R2 and R1, the 265°C PH seems a bit low for 1KG, and that’s why the graphs oscillate.

Getting tired of these massive swings in I-RoR

The main reason for this behaviour is the lack of heat. That’s why your IBTS temp, the purple line, oscillates, which then reflects on the RoR. For 300°C PH, your bean probe should be signaling close to 210°C, not 194°C as it does on this particular roast. On 1kg batches, it also helps to apply as much heat as possible from the get go. On smaller batches, there’s a possibility that the bean probe will signal crashes that aren’t there, with IBTS signaling everything normally. On smaller batches, …

[shoestring]

Thanks. yes thats how i would look at it too.
but what i dont understand is that why does the graph within a few minutes of each become progressively mental? same roast same recipe same environmental conditions

i will look into cleaning and checking the probe

the coffee tastes the same

[shoestring]

thanks, so effectively if i were to increase my charge temperature for the 1 kg roast… i should see a more consistent and controlled roast/behaviour? but again why does it get progressively get bad with each following roast? it should be crazy for all of them.

[braca19452f9m]

@shoestring

i should see a more consistent and controlled roast/behaviour?

No, you should see a nicer graph. If you are satisfied with your coffee and some line that someone said should be straighter is convincing you otherwise, don’t listen. You’ve asked about graphs, and I’m just telling you why they behave like that.

@shoestring

but again why does it get progressively get bad with each following roast?

Any number of reasons. Dirty sensor, roasting in a drafty environment, trier, plug or the other plug on the chaff collector letting air through, too much chaff accumulated from previous roasts in the chaff collector… The R2 should have the airflow control, but I don’t know if it’s just a warning light or you can pull some data off of it. It could also be the beans themselves. I don’t know why, but it has happened that some beans would create a wild IBTS RoR curve, while others won’t. I’m actually not even interested in the why if the coffee is good. It’s always a trial and error. You try, you err and then, maybe, you find.

P. S. If you recall, could you tell me what happened on these roasts, as this behaviour does look odd.

roast.world/shoestring/roasts/eouUqoKXEq1rWpBjfZDlY
roast.world/shoestring/roasts/xeM1spzWNjrR5BqwdMblY
roast.world/shoestring/roasts/M86cUFo9veFH5I_Zdx1_S

[onogrinds]

change you axis values to decrease the noise, 0 to 75?