Interestingly, I too have wild swings in the IBTS RoR curves. They are definitely somewhat dependent on batch size, but I suspect something more is going on. For example, the variability is decidedly NOT random. It is almost periodic, with a period of about 20 sec. But I also notice that OLDER roasts are incredibly smooth. The first one below is a 220g roast from last week, and the second one is from February, also 220g.
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That’s really interesting… I guess it is a really new feature and maybe the bugs are getting worked out. I don’t find very useful or trustworthy in it’s current form but going to keep it on and hope I can see consistent results.
Or @jacob anything we can do to either help test or settings which would smooth out the results (but not lose reality at least)?
In what ways do batch size and drum speed affect the ROR
From what I recently tried, with larger batch sizes BT comes closer and closer to IBTS as batch size increases, i.e. IBTS seems to be independent of batch size but BT is not… so BT is the variable.
Later in the roast, lowering drum speed will increase B-RoR. It works in reverse as well- raising drum speed will lower B-RoR. I haven’t seen the correlation as distinctly in the front of the roast… it’s either vague or not correlated.
Bruce
I meant I-ROR
I haven’t been able to establish a clear association between I-RoR and drum speed. B-RoR vs. drum speed has been sufficient for my purposes but I really would like to add I-RoR to the toolbox. If you work it out I hope you can share it here!
Bruce
Next time I roast I’ll stall the roast and vary the drum speed to see what happens, I think I still have some seasoning beans left.
I’d be very interested in seeing your test results on how drum speed affects things given other constants. 
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