Can't seem to get this machine to roast 1kg in a reasonable time frame


I have roasted a few 1 pound and a few 1.5 pound batches with no issue. It’s 1kg batches that the machine can’t seem to pull off. It’s ok, I’d just suggest that people not actually expect the rated capacity of this machine to roast in a reasonable time are with a consistent declining ror.

I’m saying all this to really ask for a chance to retest on the v2 hardware since it will likely handle larger roasts better with the new power module.


I hear ya. Having done several 1.5lb roasts, I feel that the Bullet is on the edge of being capable of roasting a full 2.2lbs of coffee if the user wanted any power to spare. That’s a lot of coffee for any consumer electric roaster to handle in this footprint given a 15amp rating.

Personal story, 10 yrs ago I built a gas-fired roaster, designed and crafted my own SS Drum from scratch. The Drum was easily capable of roasting 5 lbs of coffee and more. But, my limitation was having enough BTUs of gas power to accomplish it. It was not a “commercial” design which would have made better use of insulation, electronics and powerful burners. So, realistically, I could comfortably roast only 3lbs with extra head-room in power if needed. All of these things are kind of a delicate balance to achieve, especially for electric roasters. So, I can appreciate the challenge of accomplishing what Aillio has done.

Maybe Jacob will find some kinda tweak that can still be pulled out of the hat to give more power headroom on the 2.2lb roasts. If he can’t, I’m happy with the Bullet as designed because I roast for personal consumption. There is nothing close to it at this price point and it would require spending another $3-4K to have a 1Kg gas unit that would have the extra headroom in power.


Yeah, my goal here isn’t to shame Aillio at all. I love this machine. I’m a big fan. My personal story is that I came from a 2lb sonofresco machine that easily roasted 1kg to a full french roast within 9 minutes. It simply has a lot of gas (literally) with the propane/natural gas heating.

I got used to being able to roast 1kg easily in a small amount of time.

Now that machine could not be adjusted during the roast, and I am getting much better roasts with this machine. Just not at 1kg. My 1 pound roasts come out way better!

I’m really hopeful that the v2.0 board will help give some headroom in the 1kg roasts.

Maybe I’d have a better experience with the 220v version. Not sure.


Yep, I knew where you were coming from on your points. Gas will definitely spoil you from a power perspective! :sunglasses:


I was able to get all the way to 2c tonight in 13 minutes with a decent RoR…

I did to back to back roasts for the first time and it was the second roast. Maybe being the second roast helped…

Here is the one I did right before it but it was a 15 minute roast:


@joshua.armour, I think someone mentioned that on the Facebook group not too long ago in response to a similar issue. I forget who deserves the credit, but their theory was that the fan doesn’t run during preheat, meaning that the back end of the unit isn’t getting up to temperature. Their recommendation was to go through a normal preheat setting, actually press the charge button and run empty for a few minutes to run the fan and heat that area, then “dump” and go through a normal back-to-back protocol with the “second roast” being the first to actually heat beans.

I’ve not tried it, but have been working with smaller batches and either not having an issue with roast length or dealing with it by tweaking my preheat settings and profile changes…


@joshua.armour I’ve seen that the 2nd roast has better heat characteristics with every “drum” roaster I’ve owned including the gas-fired roaster that I built. My explanation for it was that passing through a complete initial roast gets everything in the roaster completely up to temp such that the 2nd roast reaches 1st/2nd C’s a bit faster. 2nd C in 13 minutes is very acceptable IMO, especially for a 1Kg qty in this roaster as you accomplished with the 2nd batch.

For near or max batches, I’d still like to have some head-room in heat for the Bullet for the times that I want to shave a few minutes off reaching 1st C. IMO, drum roasters are best when they have enough headroom for me to drive the roast a bit harder than the shortest user-desired period leading to 1st C. There’s always the balance between the designer’s vision or limitations and what the user wants to do and that is understandable. So, I’m speaking from a personal desire perspective as a roaster. That head-room ability is often where gas-fired roasters usually have the edge and electric roasters can bump against limitations.

Something I once saw in one of Tom Owen’s videos at Sweet Marias has stuck with me. In essence, Tom made the suggestion to try some non-std time-frames in reaching 1st C of 7-9 minutes vs the 9-12 that are often targeted. So, I began trying that with the 1.5lb batches in my gas-roaster and the results (for
me in the cup) were a nice surprise. But, you gotta have the power (heating) headroom to pull that off.

PS: Just for a bit of clarity, I’m not suggesting that a 7-9 minute 1st C is appropriate for all batch sizes or beans because it isn’t. It was the idea that Tom floated of getting outside my normal box of thinking for 1st C time-frames that I’m speaking toward. Related to the topic at hand (with large batches), I’d just like to have a bit more headroom in power for exploration, but am also very happy with my Bullet. :heart_eyes:


I see improvement in heating characteristics through the 3rd batch and notice it seems to stabilize after that. I typically run a 700g first batch then step up to my usual 850g batches.

The first two batches take higher power settings to hit the marks and then I can run higher fan levels beginning with the 3rd. There is generally good consistency in cupping the batches so I’m happy with the approach thus far.


Recently, I decided to take the time to see when my Bullet (v1.5) would announce the “Charge” statement. Prior to this, I was noticing that the Drum was typically reaching the targeted Pre-heat setting of 437F within ~12 minutes. But, I was not hearing any “Charge” statement even if I waited several minutes past that period. What I didn’t know was that the Bullet’s design is apparently waiting upon some qty of other input before Miss Aillio is allowed to speak “Charge”. :speaking_head:

So, I decided to just allow the heating to continue well past when the Drum temp had initially reached the target temperature and here is what I found.

Roast Order Target Drum Temp Drum Temp reached (in Minutes) Charge statement issued (in Minutes) Elapsed Time between Drum Temp reached & “Charge” Statement” (in Minutes)
1st Roast (cold Aillio) 437F 11:00 21:53 10:53
2nd Roast (hot Aillio) 437F 3:00 9:32 6:32

Low power issue

Thanks for documenting this. I’ve been preheating to 230C (446F) and your numbers look very much like what I’ve experienced, which I expected, after reading some of the explanations provided.


My understanding is that the ‘charge’ point is after the RoR stabilizes which is a while after the drum has reached its temp setting. It seems like it has to do with it being at temp for a while for the fluctuations in temp to stop.


I was watching all the data lines on the graph throughout the period before “charge” was announced. After the initial Drum temp was reached in the first 12 minutes, I didn’t see much change in the graph as things became flat-lined. ROR (sans its normal jumpy behavior) levels out too because once the drum temp is reached in a stable environment there is nothing to change ROR until an action is taken like charging. I do keep the cover over the charge inlet until it is time to place the funnel and charge with beans.

My impression was that there could be a factor of allowing x-amount of time to pass or for data to remain constant in x-time before the roaster is given the go-ahead to announce charge. Inquiring minds do wonder…:nerd_face:


@jacob (I think) has already told us in another thread that the firmware has access to other temperatures that are being monitored for stability. No amount of studying the screen plot will give you any insight into those other measurements.

At this point, our choice is to 1) trust that the Aillio team knows what they’re doing and wait for the “charge” state, or 2) ignore their advice and forge ahead when the pre-heat temp is achieved.

I used to go with option 2, but now that I understand what’s happening, I choose option 1. I can’t say that I’ve noticed any specific difference in my product, as a result, but I’m a rule follower by nature. I don’t really like waiting the extra time, but I figure there’s probably a good reason for that stability they’re looking for. Maybe it’s better for the machine in some way. Of course, standard disclaimers apply: YMMV, etc.


I’ve done it both ways as well (wait for the “charge” statement vs begin when the Drum temp is first reached). I can’t tell any difference in my ability roast on the Bullet either way. If it causes any product reliability issues (by not waiting), I’m all ears, but would prefer to know that than guess.

Also, it is not a matter of “trust” for me. I have no reason not to trust the team at Aillio and I do trust them. It is more a matter of understanding the roaster which requires information that I just haven’t seen.

PS: I wasn’t “studying the screen plot”. I was sharing with the other poster that I saw no visual difference in what was being plotted during the extra 11min period it takes before “charge” is stated.


No offense meant. I was also just giving an opinion.


None taken. It is difficult in a forum to understand exactly what a person’s meaning is at times (self included). I felt like doing a bit of extra explanation was all. You’re a good help to this forum and I have no problems with you at all.


@joshua.armour, I had to do a couple of roasts this afternoon and decided to allow the full time again for the “Charge” statement to be issued. This time I watched the ROR closely toward the end of the waiting period. I noticed that toward the end it settles down to a rolling 4 to 0 ROR. Then a few minutes before the “Charge” statement is issued, it settles further to an average that runs between 2.5 and 0 ROR.

So, I think you could be right about ROR reaching some particular settling point between the IBTS Drum and Bean probe temp readings. When the drum first reaches the User drum temp setting (in ~11mins), there is a slight overshoot in drum temp that brings on an increased fan for a just a brief period. The drum temp settles back down and then begins the ~11 additional minutes of leveling out in ROR until it achieves a small variance.


Hi @joshua.armour

With the latest firmware you can calibrate your exhaust fan speed if you have not already done so.
Some fans are running much faster than other at F1-F2.

Go to Menu point 6 by hitting F1 and then click top left button near the X.
This will calibrate the fan (takes a few min).

As for the 120V-V2, it will deliver 15% more power which is noticeable. Unfortunately we can not go much higher from a 15A socket.



@jonas For those that already have a 115V Bullet that is not a V2, could you give us an idea of what the cost will be for the V2 upgraded heater part? I see that the difference between the V1.5 in US dollars (Sweet Maria’s site) and the V2 (Aillio site) today is ~$134.01. Also, do you know if Sweet Marias will be stocking this V2 heater part for sale in the US? Thanks.


Thanks Jonas! You got customer 1 and 2 for the upgrade kit on this very thread!!