Ah yes… the Wall of Death. Been there; done that; never again! Taught me all I’ll ever want to know about personally experiencing centrifugal force. That 360 seconds (or whatever it was) seemed to last hours!! I’m fairly certain you’re right that the Bullet won’t reach those speeds.
Bruce
I was trying to remember the name of that carnival ride just the other day…didn’t have to do with roasting, but now you have me thinking of each bean as a carnival rider!
Careful… that could be the stuff of nightmares! 
Bruce
Tilt-a-whirl!
Yeah I don’t think the bullet drum speed can get that so high as to create that effect for all the beans. Even at 9 it seems like the bean pile is pretty stable and settling in the bottom left side of the drum. I was hoping that there would be a little more loft in the rotation.
An ImageJ analysis on the size of the bean pile for a 500g green bean batch at variable drum speeds would be interesting. Have anyone seen such an image analysis?
Some people have measured D9 around 77 RPM. Rao generally recommends 70-80 RPM for a 1-2 kg roaster. Lower RPM for larger roasters (ie. 60-70 RPM for 5-7kg & down to 50-54 RPM for 15k kg roasters).
BRADM and I were discussing drum-speeds a while back and found significant differences in the speed settings of our Bullets.
My D6 (Bullet V1.5) was 80rpm, having no issues with tipping or any other roasting defects and he had a way lower RPM at his D6 setting.
I think there is a significant variance in drum speed settings at least between the V1.5 and V2.0.
Maybe Brad can chime in and shine some light on his adjustments.
Cheers
It’s funny you should say that because after I upgraded my power board to V2, it seemed the drum speeds were quieter or slower or both. I put it down to the newer spring motor pulley but as I never made note of the original drum speeds, I can’t say for sure…
@jacob - are we imagining things ?
Mark the drum axle and count the revs.
I did it several times with 1lb. (453.6g) about
5 min. into the roast and the result was always 80rpm at D6.
Again my Bullet is a V1.5 (#001569) with about 200 roasts on the clock.
The drum speeds on my V2, measured cold and empty, are:
| Drum Speed | RPM |
|---|---|
| D1 | 42 |
| D2 | 45 |
| D3 | 48 |
| D4 | 52 |
| D5 | 55 |
| D6 | 60 |
| D7 | 64 |
| D8 | 68 |
| D9 | 74 |
Gravitron. That was the ride.
Raising this thread from the dead. I am starting out with a bullet and very interested to continue expanding on this conversation.
Does anyone have some profiles to share of a pre-soak? I am having a hard time bringing this concept to realization.
Thanks for any help!
-Thunderbolt
My usual pre soak is 1min to 1:30min at 2-3 power levels below my highest power.
If I am pushing P9 in the green phase (drying) I soak at p7.
I am always fascinated by the nearly infinite technique variations of coffee roasters.
I suppose to get at my point a bit more clearly, some context would help.
@quartzglen describes a process that makes a lot of sense, yet also feels very counter-intuitive.
SO: At “charge,” I add cold beans (450-600 grams). I reduce my heat to power 1 and, after 15 seconds, reduce drum speed to 3. For approx. 30 seconds, the bean temperature reading drops steadily, as beans “soak-in” the ambient internal drum heat, evening out at approx. 230f between 50-to-60 seconds. At that even-out point, I manually “charge” my roast by turning temp up to 8-9.
This version of a pre-soak makes perfect sense, as once the bean temp approaches the chamber temp, the overall profile isn’t affected by this initial endothermic shock and the resulting momentum chasing later in the roast.
Where this starts to fall apart for me is charging back to P7 after this soak would reduce the inflection point and force a flattened ROR curve (reducing slope). Am I getting this all wrong?
Also, side question: My Bullet R1 V2 has a max power setting of P7, what is all this mention of P8/P9?
Thanks in advance!
There was a topic about this back in 2019 that @quartzglen contributed to… latter part of 2019. In fact I found the link and inserted it below.
I tried to recreate what @quartzglen described in his posts and have followed that profile for a long time. Recently, however, I looked at some of his roasts and saw that what he did in practice was a little different, i.e. he got thru the heat soak (I believe this is similar to what you called pre-soak) faster than he described. At this point I have no desire to start again, but if I had less time invested in what I have I would pursue what @otaibimn has recently shared here- I think that is probably a very good starting point.
Bruce
The thing regarding a soak in a regular roaster is that you trying to move the accumulated heat from the drum to the beans in such a way that that they reach equilibrium in a more balanced manner.
The thing is… the bullet is not like any other roaster. You can pick it up and drop it in the trunk and take it away with you. It doesn’t have the thermal mass to hold loads of accumulated heat.
That is why you have higher preheat values. So for a soak to happen on it and not lose the momentum in a roast you gonna need to provide some form of heat to contain the momentum for the roast.
Tried a couple of P4-P5s as a soak… each time the roast extended to over 14mins. Tried P7 and was keeping in the area of 11mins max on most of my roasts.
This is what happens when you do a regular term soak on the bullet:
Thank you!
It seemed impossible for this to work as described, and it sounds like that hunch was correct.
I still don’t understand the power settings… I only have P0 - P7. Am I missing something?
What firmware are you on?
596… is that really it… ugh
i have the option to upgrade to beta 605, or downgrade to 591… But the notes suggest 596 should provide “higher” power settings for 120v PCB
You should be able to go to P9
That’s not right. You should have P0 thru P9. The only time you won’t is if you are set to Preheat. In Preheat the only settings are P0, P1, P3 and P7. And you can’t change any Preheat setting once it starts because f/w manages the whole Preheat process. Before Preheat starts you can set the target temp in fixed intervals of 5C° or 9F°, but once launched, you have no control in Preheat except to stop it.
Once in Roast mode, however, you should be able to either control power with the control panel buttons or using the RT3 s/w buttons (icons) on either side of the power slider (lower left on the Roast page).
If you can’t do that then you need to get in touch with your dealer or contact Support at Aillio and start a trouble ticket so they can walk you thru trouble shooting the issue.
Bruce
Edit- there should be no issue with f/w version related to setting P0 thru P9. I’ve used every released version from Jan 2019 (3xx?) thru 605 without issue setting power.
Charge to turnaround P9 then P7 till 135C and then P8 till drop gives me a good thermal momentum for my 1.05KG batches.