Large Batch overheat code after dump

Hello folks 1.5 user here. I have been trying some larger batches, after doing quite a lot of 1# roasts, I moved up to 2#. At 70 degrees ambient temp, and low humidity, I am seeing that to gt anywhere near 12 minutes, I have to preheat to max been using 590, then I have to run P9 the whole way almost until finally throttling it back when the beans qo exothermic. I have been running D7, and F2ish. Unfortunately this lands me in 14-15 minute range, which is not where I want to be. The oddest part is that after dumping the beans, the drum temp goes was up, up to like 680, and goes into error for a while. Does this happen to anyone else, or do you think something is wrong? Also while I am here, does anyone know what drum and fan settings lead to the beans heating as absolutely fast as they can to get my larger roasts moving along? Also, I am on a 20 amp dedicated circuit, and am using a 15’ 12g extension cord. I am hoping to change the cord situation soon. Thanks for any input.

Some of us here that have done large to max loads have encountered the same thing. The headroom (heating power) on the Bullet for max load is too thin IMO to allow you the flexibility of driving large roasts (FC and FC+) to less than 14-15 mins. I don’t like going that far either and the V2 Power Board may be a solution because it will add 15% more power. But that board is not yet available to us for existing 115V Bullets.

The extension cord is not likely your problem. I too roast from a 20amp outlet using a 14ga (25 ft) extension and there is no problem with voltage drop. The Aillio folks have also said that a proper gauge and length extension is OK for use with the Bullet.

I don’t overdrive the preheat for the very problem that you described it can cause. With my large roasts, I’m still using a 437F preheat, but keeping the power set at P9 until the beans go exothermic. My problem is that I’m roasting longer to get to the first snaps of 2nd C than I want (i.e. 14-15 mins) and I lose the ability to shorten that period without over-driving the whole roast. Having to overdrive the roast defeats having any ability to profile and that is where having the proper amount of heating headroom comes into play.

But, this is an electric roaster designed to operate at less than 15amps. There is just so much that Aillio can squeeze into that situation without changing the heat source to gas or some other inventive electric source. If I were routinely needing 2lb roasts or greater, the 1.5 Bullet would not have been the right choice as a roaster. For that, it is better to go with a gas-fired roaster. Aillio is working on a larger roaster from what I’ve read and I expect that will be a 220V model or something that can break past 115V power limitations.

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I think there’s a big issue, here. If you can’t roast full kgs of coffee beyond second crack in a reasonable time and do that back-to-back, then the Bullet R1 is NOT a viable 1kg roaster.

@PapasCup, I think you’re right that it has much to do with the anemic power available on 120V household circuits. With the plug Aillio supplies, they are only allowed to draw a max of 15 Amps from the socket. That equates to 1800 Watts. There’s also a rule that you should only use 80% of rated power for continuous loads. I don’t know if the R1 is considered a continuous load - probably not, but that would be a max of 1440W. Of course, any little imperfection in the circuit (another appliance plugged in - even a light or fan, a long wire run from the breaker, etc.) will mean that less than full rated power will be available.

A while ago, @joshua.armour measured his Bullet under full heating load and got about 1350 W, which @jacob verified as right on spec. So they’re pretty well up against it, there. The extra 15% they’re talking about with the v2 board bumps them up to about 1550 W. Maybe that will be enough. We’ll have to see

Another part of the problem might be that they test mostly on Scandinavian type roasts. (This is only a guess on my part, but it fits with some of the problems I see.) If you’re only going to first crack plus a bit, the whole roast cycle is very different from back-to-back roasts to, say, 30 seconds into second crack. I suspect that many of their event and error triggers are based on much milder roasting habits.

For instance, while preheating to 310C for my full dark roasts, I quite often get the “charge” announcement immediately followed (or even interrupted) by the “roasting started” proclamation. I’ve actually heard my Bullet utter the word “chroasting.” Meanwhile, I haven’t even gotten to the point of removing the bean plug, much less inserting the funnel and adding beans.

One thing’s certain: this machine needs some tweaks to be very useful to me in my roasting.

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I’m hoping to test the v2 board soon. I’m pretty sure it’ll do a 1kg roast into 2c fine. Most home roasters like lighter roasts so I bet most people will never hit this issue but I do occasionally roast a full kg to french. This is still a great roaster…

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Most home roasters like lighter roasts…

No offense meant, but this is exactly the kind of thinking that can kill the usefulness of the machine.

I am not and can never be “most home roasters.” No matter what I do, I can only ever be “one home roaster.” However, I am “all of the home roasters” that use the Bullet R1 in my house - a machine that was billed as able to roast 1 kg of coffee and do back-to-back roasts all day long. There was no fine print saying “as long as you’re not one of those deviants who likes dark roasted coffee.”

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Oh I agree with you. I roast a lot of darker roasts, but when I was complaining to other peers they almost all uniformly looked shocked when I talked about roasting my natural processed ethiopian yergacheffe 30 seconds past second crack. I’d be trying to get across the RoR curve and how I wanted head room to not cause the beans to go exothermic and they got stuck on roasting natural processed yerga to a oily french roast. I guess people just thought I was doing it wrong for the bean.

I concede, that bean does thrive more as a city+ to full city but my point stands, if it was a bean that had more life after full city + I’d have a hard time doing it with this machine.

I guess my comment was more to channel the feedback I heard from other peers, who said I should focus more on the bean tasting good in the cup than the ability to over-roast my beans with a pretty graph.

Since there are people now that have the V2 roaster, it would be most interesting to know what any of them are seeing when roasting 1Kg batches. :sunglasses:

Are there people with 120V v2 roasters? I thought the v2s were all 230V, still.

You are right, the only ones (that I’ve seen) talking about V2 heaters are 220V Bullet users. Sweet Marias says they will be stocking the V2 heaters, but that will depend upon when Aillio is able to deliver some to them. Frankly, I wish Aillio had forseen that need for the V2 heater so that those that want to roast full 1Kg batches didn’t have to fork over more cash for their Bullets.

“I think there’s a big issue, here. If you can’t roast full kg s of coffee beyond second crack in a reasonable time and do that back-to-back , then the Bullet R1 is NOT a viable 1kg roaster

We write that the Bullet can do 1Kg to FC in 12min. Try to take an industrial 1Kg electric roaster that uses 4-5KW (the Bullet is 1,5KW) and see if you can get to FC any faster than on the Bullet without scorching the beans.

Even many industrial gas roasters are only filled to 80% to allow a quicker roast.

When I designed the R1 everyone was doing roasts that ended around 15min. Now the roast time keep getting shorter and shorter, so obviously you will need to lower the capacity if you want to achieve a super quick roast, but this goes for any roaster.

R1 is not considered a continuous load. V2 will use 1550W as you said, but there needs to be some headroom as the R1 will automatically adjust the heating based on your line voltage, so if the voltage drops the current will go up, and we need to account for this. 100V x 15A =1500W

For maximum speed I would try F1 at least in the initial stage of roasting.
Are you pressing the PRS button before you drop your beans into the cooling tray or after you open the door?
If you record your profile in RT2 please send us a link to your roast profile or a screenshot of the roast.

@jonas - What you guys have accomplished with the Bullet (to my knowledge) hasn’t been done before (in this footprint) with a consumer production roaster for home use. That is still a huge accomplishment to me and much appreciated. I’m not going to be the guy that routinely roasts to 1KG, but there will be some occasions where I’ll need to do it. So, I’d like to better understand what the Bullet can really do (V1.5 and V2 heaters) when that moment presents itself.

I agree with you that many roasting machines are not designed to have 100% variable profile use across the maximum rated batch size. Some are actually over-designed such that the max rated use can be exceeded, but not all are that way.

If you have the graph results of the roast, I’d like to see the roast profile that you used to accomplish the 1Kg 1st C in 12 minutes. I’d also like to see was being accomplished during that roast that was the basis for the 1Kg function. What ability to profile was present and how hard was the roast being driven to reach the milestone? I’m asking these questions because I really want to know and not to be hard on you. These are important things to fully and accurately understand for users that do plan on using this roaster to it’s 1Kg potential.

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I did try a second roast (1kg roast) using f1 at the beginning and was able to pull of a full 2C roast in a reasonable time frame. It also tasted good in the cup. The only issue was that it did go exothermic and didn’t look visually appealing on the chart.

I think that I had to keep it at nearly full power and low fan to get it to roast quick enough to not bake the beans, and the result was a slight rise in the end of the roast.

I fully expect that the v2 power board upgrade will give some extra slack to pull back the power right before 1c, and allow the gas to let me coast through the end of the roast and maintain a nice looking curve.

Note, I’m also hitting 1c much quicker than the mentioned 12 minute to 1c, so you folks are delivering on that promise easily.

Here is some examples where i was more pleased.

delete me.

Joshua, out of curiosity what are your ambient temps during these roasts? Starting bean temp as well would be interesting. For me, at 70F+70F I do not think I could hit these roasts. Thanks -Marc

I’m in Seattle, and this is in my un-insulated garage so I’d say it was 50-60 degrees Fahrenheit.

@joshua.armour - Thanks for sharing the graphs of your roasts. It was helpful.

Seeing your graphs is pretty much what I would expect to see in Aillio’s graph for a 1Kg batch. While they haven’t shared their graph, I felt that it may tell the same story of what you, I and others have experienced on the V1.5 Bullet. For me, accomplishing a satisfactory 1Kg roast is more than just getting there via max settings on the Bullet. It should allow me to control (profile) the roast throughout drying, maillard, 1st and 2nd C stages without having to hard-drive the roast most of the way.

But, if the user is satisfied with the 1Kg roast they can produce and especially how it cups, then I say “declare victory”. My personal solution is backing-off the 1Kg batch size to have my desired profiling flexibility throughout the roast. Every drum roaster I’ve owned has its “sweet spots” in batch sizes. Frankly, I never expected the Bullet to have a sweet-spot all the way through 1Kg batch sizes. Sure, I’d like a bit more power headroom, but for me the sweet-spot (in profiling capability) with the Bullet would be the 1lb roast. If I need 2lbs, I do (2) 1lb-batches which gives me more roast/play-time. :sunglasses:

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This is one of my overheat warning batches. I did try to give it 20 seconds or so to stabilize before dumping. I will try F1 from now on, on this attempt I was testing the theory that someone mentioned that higher fan speeds speed up heating, to a point, and the point that was mentioned was F4, so I tried it. Bean weight was 2#

Marc, you may find the video (linked below) quite helpful to understand the relationship of airflow upon the roast throughout the stages of roasting. Given a roaster that has the power to properly drive a 1Kg roast (with profiling), the thought is to use conductive heating (low fan) during the drying/maillard phases and introduce convective heating (medium to high fan) during the period approaching 1st C and onward. The difficulty we have with the Bullet is having to over-drive the heat on a 1Kg batch which limits the ability to properly apply heat (via power and airflow) in the first phases of roasting.

Roaster School Online - #16 - Revisiting the discussion on airflow

I think the Aillio team could help themselves and us (as users) to better understand how the Bullet is designed to address the full 1Kg roast by creating their own video instruction. I know they are busy, but so are all the other Coffee Roaster builders. The team over at Mill City probably does one of the best jobs I’ve seen at instructing people on roasting. There may be things about the Bullet that we are somehow missing about how to get this roaster to achieve 1Kg batches with proper profiling. I’d love to see Aillio show us how that is done and/or explain the 1Kg limitations.

I wanted to come back and let everyone know that I now believe that my exhaust setup had a lot to do with my overheat error code. I was using a relatively long exhaust outside to move the smoke away from my setup. It was a mistake I guess. I ran it without anything but the exhaust adapter. Yesterday I ran 5 nice 750G batches and decided to finish my session with a full 1KG roast. I had to drive it hard, but it got done in under 12 minutes, about 30 seconds into 1st crack. I have not cupped it yet, but fully expect it to be outstanding. The kicker, no error code, and a normal drum temp!

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