Underdeveloped Roasts


Well, I’m roasts in with the Bullet after having used a popcorn popper and then a Hot Top. And like others posting here, it was beyond frustrating from having produced great roasts to having produced lackluster roasts. The learning curve is high. I had the additional issue of a defective bean temp sensor until I was upgraded. Having said that, I am now producing good coffee…but not great. I will post a couple of profiles later both for guidance to others but also for a discussion/suggestions about how I can improve my roasts. I roast Ethiopians pretty exclusively. I do make an Ethiopian espresso for my daughter but most of my roasts are FC to FC+.

Look forward to everyone’s input and thanks in advance. I have tried to copy a profile to insert here but unsuccessfully. Please let me know how you do it (for those who have attached their profiles).


Hi All,

I struggled with similar issues when I first got my Bullet.
I am roasting on a V1.5 with calibrated fan speeds. (Indoors)
My first big jump to better roasts and smoother RORs happened when I lowered my drum speed to D6.
I only roast 454grams (chargeweight) and D6 seems to be the ideal speed in my setup.
I usually charge at 250C (482F), lower the Power to P0 as soon as I charge and raise it at turnaround (ca. 1:10min) back up to P9.
Then I gradually lower the Power and increase the fan speed.
Here are my milestones (all temps are IR sensor)

Charge and lower temp to P0 until turnaround then P9 D6 F1
145C … P8 D6 F2
165C … F3
175C … P7
180C … P6 F4
195C … P5 F5 (this is in anticipation of the exothermic reaction at FC)
203C … P6 ( to avoid ROR crash after FC)
206C … P5
210C … F6
213C … P4
214C … P3 F7

You can put all this in a recipe, but don’t forget to add a time condition of 1min to each temp condition.

For example:
Bean temp is 145C AND time elapsed is 1 minute.
ALWAYS use 1 min, otherwise the recipe won’t run.

I usually drop my beans right around 215C.

Also, wait a couple of days until you try your fresh roast.
The beans seem to be “developing” their real flavor while they are resting for several days.
I usually wait about 4days and can recognize a strong improvement up to about the 14day mark for most of my Roasts.
Yemeni roasts seem to benefit from an even longer wait (2 weeks) after roasting.

Have fun!


Just wondering here, could your brewing/grinding method be the culprit? Have you tried to buy some store bought specialty coffee to compare?

I’ve done 15 roasts on my V2, and have gotten nothing but great results using the standard beginner’s profile from the manual (preheat to 230C, then gradually decrease power & increase fan speed). Also all my roasts look “Rao approved” naturally, with the declining RoR curve.


Wanted to add my experience here as well, since similar to others, I had 9 months of a terrible time with the Bullet and now have great(amazing?) results. I used to have a Behmor where the same beans worked beautifully, whereas in the bullet I choked every morning on my espresso. A disgusting time I don’t want to look back.
The issue is that there are so many knobs on the Aillio and I had no systematic way to approach them and no theory behind me (I only saw this thread here now)

A lot was mentioned already, but wanted to summarize my approach here which took me from terrible to amazing:

  • changed batch size from 500g to 350g ( I do 2 batches back to back now)
  • changed preheat from the default 200C to 220C ( that has a tremendous impact). I also let it preheat for a longer time. I have no system as I do other stuff but it sometimes approaches 45-60min preheat time.
  • rather than playing with power settings I mostly do fan speed. I adjust power ±1 at most during the roast but mostly keep it at P6
  • I do a lot with fan speed - I used to have only F2 - but now do F4-5 as default and regulate up or down. If I feel temp change slows too much I lower the fan speed a little when temp rises too much I raise fan speed.
  • There is actually impact from the drum speed. I have my default now at D6, not the D9 which I can test the difference
  • Changed my beans. Lastly I changed my Ethopian batch which just didn’t work on the Aillio but was phenomenal on the Behmor.

I do only SingleOrigin and for 2 months have had amazing results with these adjustments with different beans SM-YEMEN, SM-Burundi, SM-Polar Expresso.

I didn’t see this thread, but what triggered most of my changes was a notion that I read I need to let the beans develop after yellowing. That’s for the most part what I do now. I have lots of momentum in up to yellow and then take a little out and even more so when it reaches first crack where I take all out ( lower power and increase fan ) and then push up again (higher power - lower fan) when then RoR goes below 5.

You guys are way more experienced. I only roast for 3 years overall and 2 only on the Behmor and have no theory behinf me, but the above really worked for me. Oh, the roast curves between terrible attempts and amazing ones are not that different in my opinion. When I look at mine anyways. There seem to be very subtle changes that make great coffee and really don’t show up in the graphs. ( to some degree they do by reaching a certain temp 30s earlier but it’s subtle)