Coffee roaster exhaust / vents

Discuss roast levels and profiles for espresso, equipment for roasting coffee.

#1: Post by warlock »

hey roasters,
Hope you are well.

I am in the process of setting up my roaster (complete newbie / first timer)

Could you please suggest the types of pipes you have used for the vents in your roaster. I have a small 2kg setup and I am now looking to buy some venting pipes but keen to hear suggestions / recommendations. My original idea was to set it upwards, ie to the ceiling and let the air out via my roof but then I understand that the end of the pipe might not be easily accessible at most times. Although it doesnt snow where I live, I understand that the top end of the pipe would need very regular cleaning? would that be a correct assumption?

What would you recommend?

Any and all suggestions welcome :)


Capuchin Monk

#2: Post by Capuchin Monk »

Cleaning would apply to the entire pipe setup, not just the top end. The frequency of cleaning would depend on how often you roast. If possible, you want to install it where it's easier to access. Pipe through the wall instead of roof may be a better choice. The following link is for commercial duty setup. ... r-venting/

Capuchin Monk

#3: Post by Capuchin Monk »

Have a look at this example. ARC 800 Roaster

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#4: Post by mkane »

Heck, I don't even use a vent. I just open the door and let the smoke out when I'm done. Not good for my health :roll: I'm old and it doesn't matter.

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#5: Post by hankua »

I think you'll be fine with stove pipe, the install one would use for a wood burning stove. The roaster will probably connect to the flue with a flex pipe and can be cleaned from below. Over time there will be some tar like buildup, that if you wanted to clean would need chemical treatment other than a flue brush. With a 2k that could take many years, except for the top rain cap; I'd check that semi-annually at first.

With a negative air pressure gauge connected to the roaster exhaust, you can see if there is a decline in ventilation due to wind or chaff buildup.

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#6: Post by okmed »

hankua wrote:I think you'll be fine with stove pipe, the install one would use for a wood stove .
If we're talking about the same thing, I think stove pipe is single wall and requires more spacing from combustibles, 6 inches or more depending on the appliance. "B-vent" (double wall) requires one inch. This may influence the route you choose.

For clarification there is a double wall insulated stove pipe that is quite a bit more expensive.

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#7: Post by mkane »

The pipe doesn't get that hot at the end.


#8: Post by Milligan »

2kg roaster won't be a big deal to vent. I'd swing for the B vent that is double walled. Probably calls for 3-4in piping but you'll need to check your install instructions. Technically roasters need positive pressure vent pipes which are quite pricey but home roasters can get away with the typical negative pressure rated pipes like type B. Just know there may be some leakage of combustion gases so I'd be a bit apprehensive to send it through your attic. Have the roaster set up next to an exterior wall and directly vent through it is the best and cheapest for DIY. Better yet use a window and make a wooden plate for your vent using a pipe thimble to pass the vent through. Then it is easy to set up and remove non-destructively.

If you have a cooling bin pipe and exhaust pipe and you aren't venting very far then I'd run them separately. The dampers required to not get back flow into the cooling tray can be hard to find and costly. Cooling bin tray just needs single wall usually on smaller roasters.

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Randy G.

#9: Post by Randy G. »

First check building codes. Normally the pipe will not get that hot, but after long-term use the buildup can ignite- not only can, but has. I just cleaned out the pipe for my .75 kilo gas roaster and was glad I did. Not because it was hazardous in terms of ignition but because I avoided the possibility. The longer the pipe the more chance of deposits as the exhaust cools on the way up. As a firefighter I dealt with two or three flue fires, one of which destroyed a home. Yes, it was an old pipe, but still...
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Capuchin Monk

#10: Post by Capuchin Monk »

Roof penetration is always riskier than wall penetration for possible leakage which can create costly damage. :!: