I'm sharing this in the hope it interests some of you or it helps someone out there.

Green weight: 150g, weight loss after roast: 16.66%.
Dump @ 440F BT, a bit too dark, next time will dump at 435F.
After 6 days rest, I'm getting Rauch apple cider sweetness in both a shot and a 5oz cappuccino. A slight burnt aftertaste is there in the shot but I suspect that comes from the too-dark roast.

This bean came from SM's. Enjoy!

I'm drinking(brewed) the WP Kebado as I type. C+ for brewed and like it a few snaps into 2nd for espresso. I reordered this lot while it was still available.

Interesting! Seems like a perfect profile according to what I was reading here in the last weeks. I now also reduced my batch size from 180g to 150g and turned my Variac up a bit. I am now coming closer to your measurements (yes, I have my probes finally installed). I just wonder why you run the fan at max at the beginning and stop it before FC. Up to now I did the inverse, I had the fan off until FC and then started it to remove some of the smoke. Does the ventilation at the beginning of the roast improves heat transfer in the HT or is there any other reason for this? Did you run experiments on the influence of the HT fan on the profile and the taste in the cup?

Thanks for driving the HT profiling community with your posts,
Marko

Yeah, I've been using 150g batches for some time now. It's a nice round number (~3 batches/lb), but more importantly, this batch size allows you to profile your HT-B (P?) to a great extent. I'll, hopefully, share more HT-B espresso profiles (that worked!) over the next few weeks and you'll notice that I maintain very low ETs using this batch size.

As for the fan, no, I didn't run any designed experiments or tests to find out the fan influence; but I have my theories . I keep fan at max to maximize convection pre-C1 and shut it off afterwards to:
(0) stabilize ET. (1) slowly guide, by hand, the roast progress(see P x 4&5&4&5...?) from C1 start to dump. (2) reduce the amount of fresh air entering the roaster at this crucial roast stage.

There is a thread somewhere here about the HT fan, you can dig it up and resurrect it.

Yes I have a HT-P (230V version) not a B. I am using a program that tries to keep the heater at max all the time (short segments with maximal target temperature to keep the distance between target and actual HT-sensor temperature maximal). During the roast I try to reduce the heater by reducing the target temperature towards the actual HT-sensor temperature. Not that easy.

My last roast (not an Excel expert as one can see):



o temperature: 22,8C/71F
o beans: 150g espresso blend incl. lots of robusta from a local roaster to be able to compare
o weight loss: 15,3%
o Variac at 100% heater: 230V (kept constant)
o insert ET: 149C/300F
o insert BT: 132C/270F
o BT turning point: 73,6C/163F
o BT 290F/143C at 4:19 and BT 360F/182C at 6:33 (similar ramp to your Kebado roast)
o Yellow BT: 300F/149C
o fan of until FC, successively turned on 1 and 2 during the rest of the roast
o turned heater down at FC
o dump @ first signs of SC
o MET: 232C/449F

Although I ended up with the same MET as you, I obviously lost luck at the end of the roast as the ET dropped (even below the BT at the very end). Comparing this to your roast I wonder why your BT turning point is with 210F that much higher than my one. Do you have a certain trick (or some magic) to insert the beans faster than I do (maybe without opening the chute).

I did some cupping (while standing on one leg) 24h after the roast to compare the result with the roasted beans from my local roaster. It seems that my roast has more bitter flavors while the commercial one seems to be more balanced (or dull?). However, my taste buds are not very trained. Did not yet produced an espresso with this.

I found the following thread on the HT fan:
http://www.home-barista.com/home-roasting/question-about-hottop-km-8288b-fan-t9853.html#p112053
It seems that Randy G. is using the fan more like I do currently that is inverse to you. However, I can not see a convincing conclusion in that thread.

How would a designed HT fan experiment should have to look like? What about 5 equal roasts keeping the fan constant during the full roast at one of the levels 0,..,4? By "equal" I mean trying to keep the same insert/eject and heat reduction points. For the pre-FC one could be able to prove that F4 maximizes convection and for the past-FC one could prove that with F0 the fine-control is easier. What do you think?

Cheers,
Marko

If you can sacrifice the some beans, the easiest is to pick some constant level of heat that stalls the roast below the first crack. For instance, I test my roaster and controllers running a flat-line bean temperature at 375F, 190C bean temperature.

Then turn the fan on and off for a minute or so at a time and observe what happens to the temperature. It could be the fan has no effect whatsoever, or that it is so small that the contradictory ways it used make no difference.

The other possibility is more complicated. If the fan speeds airflow over the heater and drum, it can speed up the roast times if the heater has enough reserves to keep the flowing air at the same temperature as the still air. If the heater is already running flat out, or running at some constant duty cycle, then any increase in airspeed will decrease the the environmental temperature, and this will have unforeseeable effects on the the roast.

Jim's comments on testing the fan effect make a lot of sense but, Marko, I can see that your HT-"P" is already very challenging to control/profile even without the added complexity of fan effect. I say stick to Fx1 or Fx2 for the whole roast for now till you reach a stage where you can easily manipulate your ETs & BTs(or convert to a "B" ).

Now, everybody with a Hottop-B can roast this Kebado for espresso and is happy, right?

so are they sold out of this?