Air Popper Modifications -Adding a Glass Chimney or Building a Chaff Collecting Chimney

Using a Glass Roasting Chimney with an Air Popper Roaster

I have been finding a glass extension on top of a popper to be a useful thing. People discuss these types (pictured below) as being capable of increasing batch size. I have not observed that personally, but understand that the narrowing at the top might have a mild “venturi effect” and increase air flow.

They are useful if you have boosted your batch capacity and don’t want coffee getting thrown out of the roaster as a result! They also increase roast visibility over an old hazed air popper hood / top.

Lantern Chimney replacement glass for old style lamps / lanterns are the ticket for me. The ones with an opening of roughly 2-5/8 inches fit nicely inside of most Air Popper roast chambers such as Nostalgia and West Bend types. (The “3 inch fitter” models don’t fit inside most popper roast chambers, but can fit atop them if you figure out a way to mount it).

We currently stock a low cost glass chimney made by Westinghouse that fits most poppers, old and new.

People discuss these types pictured below as being capable of increasing batch size. I have not observed that personally, but understand that the narrowing at the top might have a mild “venturi effect” and increase air flow. They are useful if you have boosted your batch capacity and don’t want coffee getting thrown out of the roaster as a result! They also increase roast visibility over an old hazed air popper hood / top.

Here are 2 sizes and since the opening on the bottom is the same, both work well with electric air popcorn poppers!

Glass-lantern-chimney-for-air-popper-coffee-roaster
Glass-lantern-chimney-for-air-popper-coffee-roaster. Air Popper Modifications -Use an extension of glass to roast more coffee, and so the coffee doesn’t overflow the roast chamber

Chimney Mod Video! Demonstrating the use with the “non recommended” popper design.

Glass Chimney for Air Popper Coffee Roaster

The Best Use for a Glass Chimney

There is another application for the glass chimney for air popper roasting that is great: it turns the “non-recommended” type of air popper into a functional roaster!

What do I mean by “non-recommended type”? We recommend using the West Bend or Nostalgia type, where the roast chamber has a flat metal bottom with vents around the side. This “swirls” the coffee around inside the roast chamber. The “non-recommended type” has an air vent in the bottom of the roast chamber behind a screen. The problem with these is that they tend to eject the coffee from the popper! In addition they tend to roast ridiculously fast, resulting in a poor quality taste in the coffee.

The 2 different types of air poppers, showing the recommended type that swirls coffee, and the so called non-recommended type. But add a glass chimney and the later type works pretty well! Especially for dark roast lovers.

But … placing a chimney on top fixes this: it deflects the coffee back into the chamber while roasting, and it allows you to increase the batch of green coffee per roast. The larger batch size tends to slow the roast cycle down and result in a better cup. It also works very well for dark roasts, a great option for people who can’t get other popper types to roast dark enough to their taste.

I still feel that the “non-recommended type” isn’t the best and needs other tweaks to improve the roast, namely slowing it down further to 6-7 minutes.

We currently stock a low cost glass chimney as pictured below, made by Westinghouse that fits most poppers, old and new.

Chimney on the non recommended air popper coffee roaster
Chimney on the non recommended air popper coffee roaster – this popper was in 2nd crack – note the smoke! This is a Cusinart model still being produced (in 2021)

Actually there are a couple other options for extending roast chambers in air roasters:

Coleman-Glass-Lantern-replacement
Coleman GlassLantern-replacement can work for coffee roasting chamber

One that is discussed online is the Coleman Lantern Replacement Glass – wide tube of glass with parallel sides. If you look online you will find several types. A rarer type is tapered, and I understand it fits nicely in the poppers! (For a non-glass type people would use those special tapered Salmon Cans!)

Mason-Jar-Lantern-Glass-Bottomless- for coffee roast chamber extension
Mason-Jar-Lantern-Glass-Bottomless- for coffee roast chamber extension

Another option is a Mason Jar with the bottom cut off, used as a lamp glass in some craft projects. Check Etsy or other online sources.


Vintage Article from Tom: Experiments in Building a Chaff-Collecting Chimney

DIY project to make a chaff collector.

Creating an experimental top for your roaster from household trash can be fun and rewarding. Any changes you make in the hood on your air popper will change the roast because you are modifying the thermodynamics of the air flow. Here are some photographs and notes of a chimney I built that traps chaff very effectively. The roasts take slightly longer with this device installed. I tested it with a West Bend Poppery II, but it would work with any popper with minor changes.

Air popper roasting chimney
DIY Air popper roasting chimney: Cut three or four vertical slits in inner can so it can be shoved into the popper chamber opening.

The cut three or four vertical slits in inner can so it can be shoved into the popper chamber opening.

RTV High temperature sealant Coffee Roasting Chimney
RTV High temperature sealant Air Popper Modifications: Cut hole in bottom of larger outer can, tabs are just to help fix the 2 cans together.

Then …Cut openings for air flow. Seal cans together with RTV. wrap strips of window screen over openings on outside. Double up on it to prevent any chaff from getting through. See auto air filter idea below…


The design here is very simple. I am not going to provide step-by-step directions since I think the construction is obvious, and this design could be greatly improved upon by almost anyone who attempts it (see note below).You jam a can into the chamber. Chaff blows up vertically, then lands in the trench between the two cans. It is drawn there because the only air outlets are the vents along the bottom of the larger can. They are covered with a double layer of standard window mesh. The top of the can is covered with a lid from a clear glass casserole bowl, so the roast is very observable. A thermometer (not pictured) pierces the side of the inner can and is suspended in the air stream. The cans are joined with high temperature RTV sealant.

The irony about this chimney design is that I don’t think its a significant improvement over the standard popper hood. Chaff is no big deal, I think its smoke that concerns more poeple. Well …this whole design was intended as a smoke reducer but I never got around to it. How would that happen? A lightweight automotive air filter would be added, encircling the lower part of the outer can, over the openings/mesh. I think that if you could find a cheap paper auto air filter that didn’t restrict air flow too much, this design could really work. I’m just too busy right now to investigate the options …

Please let me know if you have any ideas, innovations, or chimney building success stories. I’ll be glad to post them here, or feature your invention in an article of its own.


2 Responses

  1. I roasted for many years with a modded Poppery 1. I used the glass chimney on my popper with a “candy cane” vent pipe made from light weight dryer vent. The candy cane was directed into a bucket which effectively caught the chaff coming off the roast.

    A couple of poppers I had utilized a collar of high temp silicone for the chimney to rest on top of the opening when the chimney was too large for the popper opening. I just lightly oiled the chimney and squeezed a generous amount of the silicone around the base. After the silicone set, the chimney easily released and was cleaned off of any residual oil.

    1. This sounds like a great way to attach a chimney in a snug fit, but also be able to remove it. Never thought of this! Thanks for sharing that idea…

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