Exhaust hood options

Black Stripe roasts a lot of coffee (Dashboard → Users → Search ). Makes the installation very credible.

A couple things to keep in mind-

  • Current Aillio guidance recommends an air gap between the roaster and the fan-driven vent line so that the exhaust fan isn’t defeated (especially at low settings) by an in-line fan.
  • It never shows up in installation photos, but there has to be a source of make-up air when venting to the outside of a closed space in order to not create a low pressure area around the roaster. In a really well-sealed building the roaster will be throttled for air which will affect exhaust fan flow rate.
  • I see they gathered the cooling tray exhaust too. If you do that (seems like a good idea!) you probably need to provide a fan to move a little air under the roaster since the cooling tray provides that function- even when not cooling, that fan is running at maybe C2.

Bruce

Edit- when I commented on cooling tray exhaust in Apr 2020 I didn’t know the cooling tray fan was kept spinning at low speed to provide air movement under the roaster.

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Thank you bab, for verifying Black Stripe’s setup. I’m thinking that a cooker hood with 380m3/he might be a good idea… :bulb: I’ve been given a 4” inline fan, tho flow rate is only 53m3/hr - what’s the flow rate of the Bullet’s fan at F9?
The make-up air also makes perfect sense - I’ll look into that some more.

No clue! Calibration is in rpm only with no equivalent flow rate mentioned I’m aware of.

Bruce

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My range hood has 3 speeds: 300/510/680 cfm (500/860/1160 m3/hr). I use low speed during preheating, and have also roasted at low but then the kitchen smells of coffee a bit. Medium speed is perfect. Don’t need high speed, at least not up to the first snaps of SC.

I don’t use any ducting. I roast up to 450g batches, and the most I’ve ever done in one session is two batches. Hope that helps!

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Bradm, that sounds exactly what I’m looking for. That’s quite a high flow at over 1100 M3/hr - What manufacturer number is the hood pls?

Kobe: CHX91 SQB-1 Series | KOBE
Mine is the standard 30" under-cabinet version.

@bradm’s setup is also my planned setup. My range hood is up to 900 CFM in 6 different speed settings. Good to know that at 510 cfm setting that worked well.

@Scott_Waugh my range hood is this one: https://www.homedepot.com/p/Cavaliere-30-in-Convertible-Range-Hood-in-Stainless-Steel-SV218Z-30/205896803

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I’m in the planning stages for a basic venting solution (I haven’t even unboxed my R1 yet!). Any advise on a filter material to place in front of the in-line fan? I don’t want to kill too much of the air flow, but also don’t want to ruin the fan by gunking it up.

@forrey45 What filter material to do you use in your hood?

Thanks! Ben

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See note #10 above (@bertje1959) - hard plumbing plus a box to hold the same filter material as the cooling tray for easy maintenance. Very nice setup.

Bruce

I know it is strange but I found in home depot 12 Inch by 18 Inch by 1" Thick Floor Pads white for polishing, they fit on the bottom of a sanding machine. I just cut them to size and they have worked very well for me.

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I actually managed to get my Bullet set up in a good spot in the kitchen and working well with a direct (unpowered) vent. I printed the exhaust adapter in nylon and connected directly to rigid 3" duct, which vents directly outside through much less than one meter of total length with a single 90, and a commercial Seiho vent cover. The Aillio flows so little air even at the highest fan setting that flow doesn’t seem to be a problem, and there is a window only a meter or so away that I can crack for make up air at the same pressure. (I have forgotten to open it a couple times and didn’t notice a difference, however.) I’ve done a lot of overlay and playback roasts with the same beans over many days, and see no significant variation with wind/weather/furnace running/wood burning stove operating - variation in preheat at the time of Charge is a much bigger factor. I think a directly connected vent can work just fine under these conditions: short enough and close to a window that can be cracked to short circuit any pressure differential across the roaster. I have roasted on some windy days, but I suspect if it were windy enough - like a major storm or wind event - I might be able to observe some effect of that. Up here in in the hills above Silicon Valley, we do get some serious wind from time to time - 40-60+ mph gusts - and I’ll probably avoid roasting if it’s really blowing.

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Here’s my variation on venting. Removable.

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image

Finally got off my butt and got everything working, checked ,etc and just did my first seasoning roast. A little bit awkward setting the Bullet up at an angle on my stove but it was the only way to see the front panel, making sure the vent will suck up the exhaust etc. It works - that’s all that matters :blush:. The hood vent did great I can see it suck up the exhaust at a setting of 4 (out of 6) nicely and my smoke detector did not go off!

UPDATE: just tripped my smoke detector with the second seasoning roast because it was darker roast…need to remember to up the vent fan! :sweat_smile:

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The range hood should work OK with enough flow rate but remember to have a source of make-up air. If you don’t have a partially open window/door the extraction fan will not move the air properly and you’ll get smoke (can be hard to do in cold weather!).

Bruce

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@bab I think what happened is I really pushed it into the really dark roast range and didn’t crank up my hood to draw more flow out. I did have a window cracked open (too cold to open more since it was 37F outside) but I know my make up air fan also kicked in drawing air into the house. I didn’t get visible smoke per se, so it leads me to believe it may be a build up of particulate in the air from the first and second roasts. I left the two seasoning roasts as public if you want to check it out on roast.world :slight_smile:

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@blacklabs At over 460°F, yeah that was really dark but exactly what you needed for seasoning. Should have been pretty much done with 2C. Beans were really oily, right? That was a good seasoning roast as was the 2nd. I roast pretty dark and can hear 2C quietly starting above about 442-ish °F with the washed Chiapas beans I’ve been into lately. By the time I dump the roast it’s about 40-60 sec into 2C. It’s really hard to hear 2C so I tip the bean chute cover and angle it to reflect sound toward my ear- be careful! The bean chute gets really hot!

At the Yellow point you have about 56F° separation between BT and IBTS. Keep track of that number as (if you have the same batch size every time) it will tell you when the IBTS needs cleaning- when the difference in those 2 numbers shrinks by say 4F°. I treat that as the indicator that it’s time to get out the tool kit and cleaning supplies for the inside of the face plate, door glass; plus Q-Tips & alcohol for cleaning the IR sensor of the IBTS.

Another thing to note- if you charge with a larger batch size, the difference between IBTS & BT will shrink. I treat IBTS as sacred and presume it’s the BT probe that reads higher as batch size increases (that’s a guess but I think I’m right; at 1 kg they’re close to the same value). It just seems like a good idea to stick with the same batch size for awhile so you can get comfortable with Bullet response to preheat temp, power, fan and drum speed settings. If you do change to a larger batch later you’ll have more confidence how the roaster will respond to the controls.

Bruce

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I think that was an errant mouse click. Trying to figure out the software interface and the panel all at the same time! Not trivial initially :sweat_smile: There’s some questions I’ll post in a new thread.

I arbitrarily decided the YP was at 343°F because any estimate based on color is too subjective. So I picked out that temperature difference at what you clicked cuz it was close to my personal “standard” YP value.

So independent of how you might want to mark YP (since it figures in the calculation for the Development graph), I’m suggesting that you keep track of that temperature difference at some specific IBTS temp of your choice so that you can estimate the time for recurring maintenance.

From what I’ve seen in my roast data, YP is pretty close to the maximum separation of BT vs. IBTS. I think it’s likely related to moisture loss since this is in the middle of the drying phase.

Me


venting solution for me is using 3D file which was provided on website to make it. This setup is neat and clean for small shop to do.

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Neat option - Its not visible, but I guess you use the two adapter parts that offer an air gap, right? What kind of filament were you using. I’d like to prevent using ABS as it is far from being usable indoors without a certain effort in venting and temperature control. PETG will very likely not withstand the exhaust temperatures.

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