Beans in the exhaust duct

Just ran into something odd. With the funnel in place on the bean chute, I usually just up-end the measuring cup into the funnel (550 gm). The beans normally feed into the drum without issue. The previous two times they seemed to hang up in the funnel and it took some coaxing to get them thru. When it happened again today (3rd time?) I looked from the rear of the duct (chaff collector off so I could see) and found the duct had a bunch of beans that had gone into the duct instead of the drum!

I apologize for the image quality. The beans at the far end (bean chute end) are out of focus but still distinguishable.

The Fan speed when I charged was F2 so I doubt they were being sucked in toward the chaff collector. I haven’t removed the front plate yet (it’s cooling). So the question for y’all is…

Has anyone dealt with this before? Since it’s happened now 3 times in succession I have to believe it’s not happenstance.


Yes! This has happened to me a couple times - unfortunately I can’t pinpoint exactly when I’m the roast cycle it happened. I noticed it one day when I went to sweep the dust out of the tube. There were quite a few beans there & from the looks of them, they’d been there a while.

I cleaned them out and haven’t had it happen since, now about 100+ roasts later.

I am more careful these days to make sure no beans are left sitting on the little crossbar where the funnel rests, so I’ve chalked it up to that. But truly not sure what causes it.

Hi Matt-

Thanks for the reply.

I started a trouble ticket and the first question the tech asked was “do you have an exhaust line connected directly to your roaster” (I don’t). The second question was “did you get the funnel set in place backwards”. That answer has to be more uncertain. I’m conscious of the how it should be aligned each time I pick it up, so it seemed unlikely I would get it backwards 3 times in a row. But lacking any other explanation all I can say is… maybe?

The first 2 times was with a new-to-me decaf bean. Very slow to feed till it jammed in the funnel; I blamed it on surface friction of the SWP’ed beans. After I finally got the beans out of the funnel I saw more than a couple stragglers on the little crossbar and at the bottom of the chute. I frequently see a couple beans on that bar and brush them down into the drum (otherwise they end up looking like a quaker if they drop in when I eject the beans). But this time I saw maybe 15-20 beans in the chute. It seemed odd to see that many still in the bean chute.

The 3rd time was with a blend which is a mix of small, medium and large size beans. I suppose the mixed bean size could have been an issue but I’ve roasted this blend more than 30 times without any problem.

This is the first time I’ve experienced this “bean jam” in perhaps 600 roasts (I replaced the control board & lost the internal record the Bullet keeps). So at the moment it’s wait-and-see. Well… unless Aillio support has another example of dumb-things-we-do-to-our-roasters! :astonished:


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The only time I had this happen, I did notice I had inserted the funnel incorrectly. Now I try to be extra careful.

I did another roast of the suspect decaf beans and was surprised to find they were the culprit. I’m guessing here but it appears the surface of these SWP decaf beans has a slightly higher coefficient of friction than non-decaf beans. My habit is to pour as many of the 550 gm batch of beans into the funnel as I can and keep pouring till everything is out of the measuring cup. This time I noticed that these particular beans weren’t feeding thru the funnel as fast as unprocessed beans do. There was a critical point where there were so many of these decaf beans pushing down on those feeding thru the narrow opening that they packed tightly and the feed stoped altogether. When I I saw the jam starting I eased the feed rate and it kept going slowly… very slowly.

So the question that nags is whether or not these beans (decaf Sumatra Aceh from SM) are representative of all decaf and I’ve just been lucky or if they are unique in terms of how fast they feed thru the funnel. Dunno. But my new mantra is something like “patience”.


I’ve had it happen a few times too. I think I’m my case it was the funnel being a little off and dumping the beans in too quickly. I try to stream them in a little more slowly now

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