Hot Rod Home Coffee Roasters: The Spirit of Invention

For some people who roast their own coffee, off-the-shelf home coffee roasting appliances don't cut it. Either they don't offer enough control of the roast, are too expensive, or just don't allow the roaster (uh, the person that is) to express themselves. The homemade or seriously modified commercial roasters on this page are alternately amusing and intimidating in appearance, but whatever the case, they probably work very well. And if they don't, you can bet they will be reconfigured endlessly until they do by their respective owners. A disclaimer on behalf of every roaster on this page: modifying electric and gas roasting equipment is dangerous. A 120 v shock isn't half as bad as burning down your house though, and that is a serious possibility. When you build or modify a roaster, you assume a great deal of risk, and should be extremely cautious. You never, ever, ever walk away from a machine when it is in use. And you should unplug electric roasters even when they are off. Be safe, have fun. Most of these people are regulars on the Sweet Maria's Homeroast List. Also see my pictures of coffee roasters...and of course, our Coffee Library page.

For more on homemade home roasters - or modified roasters - check out the Using/Building Hot Rod Roasters section of the Sweet Maria's Forum

Alan Kane's Residential/Industrial Roasting Machine

Alan built this system from the ground up. Diamond plate sheeting, a salvaged residential 40KW furnace, a Jenn-Air commercial hood unit, and other things too technical for us to understand. He also uses a shop vac connected to Home Depot bucket for cooling. View more at Allan's Photobucket page. http://s907.photobucket.com/albums/ac272/civilkane/?albumview=slideshow&track=share_email_album_view_click

Gene Schrier's Motor-mounted Turbo Crazy and Cooling Tray

"The stainless unit the roaster is mounted to is a steam table insert pan upside down. It holds a 1/40 hp gearhead motor that turns 90 rpm. The motor is coupled to the stirrer by a 1/2 inch stainless shaft. The roasting chamber is a Farberware buffet electric fry pan. The unit on top is the heating unit from a Deni turbo oven. The stirrer is made from a handy chef 6 in 1 utensil."

Now 40% less Ugly!

That is the claim Derek makes for this creation, originally called the "Ugly Roaster" but becoming more refined quite rapidly. Derek is in South Korea and doesn't have access to all the roasting machines we do, so building his own has as much to do with distance than demand. It basically sits on a propane burner, cranked by a fan motor, and cooled in a strainer over a fan - even if it is ugly (it's not) it works! The pics of the roasts look very even.

Here is Derek's site for the roaster, and this link is the building process.

Lighting Effects Tell if the Roaster is Heating or Cooling....

Casey Dodge writes, "This is my first home roaster. I built it out of a Poppery II and various bits from the kitchen and hardware sections. I separated the heating elements and the fan and ran them through a single 3 position switch. The body is a stainless canister and the bowl is a Dietz lantern chimney which fits perfectly in the shortened popper chamber. I built in "ground effects" using LEDs in the acrylic legs that change from red to blue as the heating element is turned on and off. The roaster is small and can only roast about 1/4 cup of green beans at a time but it looks great and gives good results." Visit his blog for more and his amazing craft as a maker of cutlery.

After one session roasting in a frying pan, I was hooked on roasting!

Here's my roaster: It is custom fit to my cheap Wal-Mart grill.
It's obviously got some familiar design elements.I welded, cut, ground, and fit each part. The drum is SS, with a fabricated funnel-shaped end and vanes from flat SS cookie pan.
I made the flanges by welding, drilling rod and holes, cross drilling, etc.I used bronze bushings in the main drum shaft.
I used parts from a hand-drive worm gear winch for the worm drive.The top assembly tips forward to pour the beans.
Hopefully everything else is pretty obvious from the pictures.
It works great. I've roasted about 2 pounds (it seems optimum to use about 1/2 pound per batch).This was a LOT of work

Thanks, Jim

Control-Shift-R = Roast?

Here's my homemade PID'd West Bend Poppery I setup. The PID is a Fuji
PXR4 that can be used standalone or interfaced with my laptop via a
USB cable. It's pretty much self-contained except for the external
variac that I use to control the fan as the roast progresses. The
roast chamber was built out of the original bakelite tube from the
Poppery, a 3" diameter glass tube, and fitted together using hi-temp
RTV silicone. There is a screen at the bottom of the tube so you can
remove the chamber to dump the beans.

Matthew P. Williams

Doug Boutell's Metamucil Roaster

Felix Dial I wasn't sure if the split-wired poppers I use for coffee roasting fit under "homebuilt roaster", but I figured I'd send you the URL to my webpage and let you decide. I've modified poppery2's, poppery 1's, 1250W wearever pumpers, and a 1400W wearever pumper that's my main roaster. http://members.cox.net/felixdial/popper.mods.shtml I use a control station with dimmers to alter heat and fan. The webpage isn't entirely up to date as I now use a variac to modify popper heat. I must add that I bought the variac (Powerstat 3PN116C actually) in mid-November, which was a few weeks before you started selling yours. I hope this isn't an issue. Thanks. Felix

http://members.cox.net/felixdial/popper.mods.shtml

New! Felix now has a PID to control roast chamber temperatures in his setup. Here is a link to that page: http://members.cox.net/felixdial/PID/PID.shtml

Ron Kyle has taken it a step further.

He came up with a drum design for a Barbecue Drum Roaster and now he will make one for you! I have cupped the results of his roaster and, especially the medium City+ roasts he sent me, are excellent.

A close-up of Ron's drum.

Neat hinged end.

Note: Sadly, Ron Kyle passed away after a short bought with cancer. Ron took the whole idea of barbeque drum roasting to a new level, and I think his small drum-making business was guided much more by love of home roasting than anything else. Here is a note from his friend Rich below. We'll miss Ron ...
- Tom & Maria - Sept '08

"Dear Friends,
It is with deep regret and sorrow to inform that Ronald Kyle has passed away peacefully in the mid-day hours of Wednesday, August 13, 2008 with loved ones all around. Ron was diagnosed with cancer approximately 3 weeks prior to his death. Ron was a valued and respected member of the community, and changed homeroasting forever. Ron was known everywhere for his unending kindness and generosity to all. He will be greatly missed. If anyone has placed any orders with Ron, and have yet to receive your product, please email me at the link below. I will do my best to keep track of everything. No one is checking emails at the moment and it may be as much as a month before things begin to function somewhat normally, if then. So if there are any inquiries, please let me know and I will do my best to get things resolved. Please be patient as we are trying to get the wheels turning without our beloved Ron at the helm. I have no doubt he has already got a 50lb RK Drum turning in heaven! May God Bless Ron and his Family through this difficult time.
-Shane Lewis (Friend)
With Respect, Rich Adams"

Phil Kniss "Heat Gun Bread Machine" Mash-up

Phil writes, "Here is a link to some pictures, with descriptive captions, of the roaster I set up in my garage, using a $6 thrift-store bread machine and a heat gun. Feel free to post these as you wish. I am able to roast a one and a half pound batch at a time."

Here's a link to more pictures of Phil's Facebook page. It's a neat design with some great solutions. (I like using the lamp base to hold the heatgun in the right spot.)

My .02 cents. As important as good roasting, there's also good cooling. I really like his design. Note that it has 2 screen levels, and it would cool best when the entire screen is evenly covered with coffee. If you put a little coffee on there, covering part of the screen, it pulls air around the coffee rather than through it. This is a lot like the cool bed on a bigger roaster. So you need to build this in the correct size for your batches, or block off parts of the screen for smaller batches. It's a great, super-effective design.

The "TurboCrazy"

A long, long time ago I tried to roast coffee is a West Bend Stir Crazy popcorn popper. It seemed ideal, with a mechaincal agitation arm, a hot plate, a see-through cover. But it was underpowered and the coffee never reached roast temperatures.

Well, some people don't give up as easy as me, and they came up with a new top for the Stir Crazy, from a convection oven, and some other modifications to turn it into a robust, cheap coffee roaster.

Peter Bishop has a web page describing the transformation process. His roaster is pictured below...

Peter Bishop's rig

Ron's Stir Crazy base with some modifications

Ron has set up a photo page for his roaster (I am including some here since Yahoo photo pages sometimes disappear). Notice all the great features here: you can see the roast, you can roast a good quantity, the roast develops at a moderate pace, and the overall build is easy and fairly inexpensive.

Ron's TurboCrazy. The Galloping Gourmet top seems to be the easiest to find and most popular among TurboCrazy modifiers

Finished roast. The time ranges from 10 to 14 minutes to second crack depending on which convection oven top you use and how much you roast. First crack is reported at 6:30 to 8:00 or so. This is allowing a good even roast progression and a nice delay between 1st and second - an indicator of a good, controlled roast development. The batch sizes are close to 1 Lb of green coffee! Also, the stir blade automatically reverses itself if it faces too much physical resistance.

HG/DB ... that is, Heat Gun/ Dog Bowl roasting. This amazingly simple method works great, and allows you to view the transformation from green to roasted right in front of you. It is low-tech and lets you use your senses to adjust roast agitation on the fly. Plus, it's roasting with 3 items (including the wood spoon) that you probably already have!

Here is a picture from Martin Lipton's photo page of the HG/dB technique in action

The noble Poppery ... always an option. Straightforward, easy, but increasingly hard to find. And here is my all-time favorite photograph someone sent in of their Poppery with elegantly simple modification for extending the roast chamber height, and chaff collection. What more do you need?

Finishing up around Vienna, with second crack evident. Notice added smoke.

Chris Arnold was able to make a drum using a George Foreman Rotisserie. Here's his description and here is a web page he made with complete photos:

"Like many others, I wanted to roast my own coffee beans, but did not want to spend $200+ on a pre-fab drum, nor did I want an electric roaster (for various reasons). I already had a gas BBQ grill so... I bought a Char Broil Rotisserie at Home Depot for $33, and was now on the lookout for a drum. I searched for the elusive FrontGate (or equivalent) stainless steel trashcan with holes in it (no luck). This included Home Depot, Lowes, Ikea, Staples, Office Depot, 2 Restaurant Supplies, and 3 Thrift stores. I found a George Foreman Rotisserie that had a cylinder-shaped basket at a Thrift Store. I thought it would be a perfect coffee bean roasting basket. This purchase set me back $19. It works really well, the roasts are very even. I use a thermometer placed right near the drum to get more accurate readings. I pull the spit off with gloves, and spin it in front of a household fan to cool the beans. The beans pour out easy, and almost all the chaff stays in the bottom of the BBQ, so that has to be cleaned out occasionally. The only tools I needed for cutting and bending was a pair of linemans pliers. After a little tweaking, I have a great setup for under $60. I plan on buying or making a better drum, but for now I am happy."

David Solomon had a great drum fabricating idea, and it takes about 10 minutes to make - use clamps and pop rivets with 2 metal desktop pencil organizers ...voila! Rivet in a some vanes and thats it...

Alchemist John, known to all on the homeroast list, has been using a home built drum roaster for some time. Wow, purple chasis and all. No wonder it is called the Zen Roaster. It is a close kin to the professional sample roaster design and even looks a lot like the angular Primo roaster.

Mike Faber has a unique versiion of a roaster with a 2 Lb. batch capacity! It might remind you of the Stir Crazy / Turbo Crazy designs others use, but it is unique and looks quite elegant to boot. It is a Farberware electric skillet that has a few modifications.

Dan Gray Unfortunately, we can't find a cool popper like Dan's because he is in Europe.

Here's his comments on the Rival Popper:

The first thing I discovered was that the plastic lid that comes with the unit is completely unsuitable for it's new role - it becan to melt after three minutes and by six minutes was distinctly soft. I threw it away after a few days.
The second discovery was that the chamber doesn't really hold enough beans on it's own for a decent roast. More that a couple of scoops worth and they were spat out around the kitchen this wasted alot of coffee and ment that I could only roast in small batches. I really wanted a few days worth rather that just two cups of espresso! The solution was to glue an extension made from a food tin to the top of the unit using a non-thermal glue (superglue in my case). This enlarged the roasting chamber significantly so I could roast more and delivered chaff away from the unit.
The chaff was the biggest problem as it's hard to fit a chaff collector and it blows everywhere. In the end I made a simple lid from a kitched seive and some meccanno. It's not ideal and if I can find some flexible ducting i'll modify it again so that the air is delevered away from the roaster before it's filtered.

Scott Marquardt wrote me a note about recent updates to his 2 home made home coffee roasters, Here is his note, with links to the full pages:

I've done a lot of mods to my popper, but I figure some other things I've done are more interesting and would be something new for the page -- a page that does a great job of showing the diversity of ideas in play out there. These are definitely new, and you're welcome to grab any pics that strike you as worth adding. If you have any questions about 'em let me know.
open sky roaster
The link is a "home" roaster only in the sense that since I couldn't afford a road trip with the family this year, I decided to accept the invitation of a tiny farmer's market in the area as a summer project for my 13 year old son and I. I approached a friend who's a superb machinist (I could tell you things), and we hammered out the prototype in three weeks (with tweaks in successive weeks). It's now technically a commercial roaster, though we're going to finish the season in the red with only a lot of fun to show for it. We actually have great habitual customers, but it's a SMALL market and I've invested a lot with a view to helping the market attract more interest -- a tent for people to sit in, chairs, tables, etc. I may not be the world's best businesman, but I've made friends and influenced people!
radiant coffee roasting
Anyway, the radiant thing (second link) was actually what I wanted to focus on this year. Be sure to see the link to the backstory. I still have plans to architect a system where a coffee shop could roast a pound for a customer while they wait and sip a brewed cup. I think the thermal carafe could do that. The ceramic element (barely introduced as I put the project on pause) is key; that shortwave IR from the halogens just doesn't give a uniform roast.

Best regards! - Scott

"open sky roaster", weber powered.

radiant coffee roaster

halogen heat source, vacuum thermos roasting drum

this goes there, the entire system.

Home Roasting in Japan: Tsujimo from the homeroast list emailed these links to Japanese sites. The array of home roasters are amazing, and presumably these are all homemade. (Some are so sophisticated it is hard to believe! Others appear to be one-offs, but for light commercial roasting.) Here are a few pictures, or you can check out the links below.

Not everyone is so over-the-top.
Here is a simple can held over a propane burner

Links:

• http://www.1jb.jp/jisaku.htm http://www.flavorcoffee.co.jp/3f/r-index.html
• http://www.motoki.com/coffee/kama.htm
• http://www.tsujimo.com/coffee/uploaded/01192053492.jpg
• http://www.rodan24.com/teru-dabe/mov/baisen.MPG

The Lone Roaster!

This is the SS Stovetop Popcorn Popper we sell, driven by a drill - great design! Here's the details on it from the Lone Roaster himself: Dear George,

"First, a little background. I decided to build a roaster because the Hearthware roasters I used before that (three of them) only lasted about a year or so, and then the fan would give out. I also wanted a roaster that would handle larger batches. So I went online to Sweet Maria's (where else?) and ordered an SS Stovetop Popcorn Popper. I modified the popper and built the drill stand in March and April of 2004, and it's still going strong.

What you see in the pictures...

The top picture is the entire setup in my garage. The popper is sitting on a two-burner electric stove running at 700 watts per burner. The thermometer is a TecPel 316, dual channel, Type-K digital thermometer. It also has an RS-232 serial port that can be used to connect it to my PC. With it, I can not only record and graph my roast profiles, but also the cool-down cycle at the same time. The shiny SS item next to the thermometer is a canning funnel that I picked up at my local Ace Hardware store. It works great for pouring beans into a mill that has a somewhat narrow opening.

I picked up the drill at the local Home Depot (the cheapest variable speed drill they had), and built the stand for it from scraps around my woodshop. The knob below the drill is used to control the speed. I've found that 60-100 rpm works best. For consistently even roasts... the smaller the batch, the higher the rpm.

Although I don't have a picture yet, I took a somewhat different approach to cooling. Instead of putting some kind of basket on top of a fan. I built an enclosed box with a screen for the bottom. And then attached my Shop-Vac to the lid. This not only sucks a LOT of air through the coffee, but also removes virtually all of the chaff without getting it all over the garage. The box will cool the coffee from an indicated temperature of 360-380 degrees (with the temperature probe about 1/2" or less above the hot coffee) to less than 100 degrees in about 1-min, 30-secs to 1-min, 55-secs. (depending on ambient temperature).

I've enjoyed using this roaster immensely. I've roasted batches as small as four ounces and as large as two pounds. Normally, I roast one pound at a time. In our house, this lasts about five days.

In the almost two years that I've been using it, I've only encountered three problems:

1. When I first starting using it, I quickly found that the cast bevel gears were very rough and tended to catch and jam. To fix it, I smoothed the gears using my handy-dandy Dremel tool.

2. Not long after that, the plastic window fell into a batch of coffee in the middle of a roast and shriveled up into a nasty looking ball of plastic with coffee beans and chaff embedded in it. The wooden knob on the lid had a screw in it that also held the plastic window in place. The knob split from the heat and the screw fell out. I fixed it by pop-riveting a piece of thin sheet steel in place over the window opening. After the first few roasts, you couldn't see through the window anyway.

3. Keeping it clean! The pot is easy, but because of the way it's designed, the lid is a pain! Any advice in this area would be greatly appreciated.

It's been quite an adventure and education roasting here in Flagstaff. We're at an altitude of 7,000 feet and the weather can be extreme. Temperatures range from the hundreds in the summer to below zero in the winter. With a 10 to 30 mph wind, you can imagine the wind-chill! Humidity ranges from 100% down to 3%. In a single day, we can get a temperature swing from the 20's up to the 70's. 50 degrees in less than 24 hours. This, of course, has some interesting effects on roasting. Brewing is fun too, since water boils at about 199 degrees here.

Well, that's my story. I have a web site www.loneroaster.com and am in the process of putting up pictures and instructions for building one of these. Feel free to check it out or ask questions. I think anybody who truly enjoys coffee should "roast their own"...


Sincerely,
Bill Acor,
the Lone Roaster

Bob Yellin has a very interesting setup, a "heavily modified" Sirocco (if you are not familiar, it is an obsolete model made in Germany by Siemans. I think I have more pics on my coffee roaster picture page).

Here is Bob's description: Modifications: I've split the heater and the fan into two separate voltage inputs and each can be plugged into the AC line or Variac(s). This took some doing! Although the photo shows the Sirocco's original control knob, I've got it bypassed. I replaced the original paper chaff filters with a homemade metal mesh and drilled through for placement of a thermocouple for data logging and (now) PID-controlling the roast. I now have such complete control over the roast, I feel like this roaster is almost a lab instrument. I've roasted up to 150 grams very successfully but usually keep it to 100 grams. If this is not "heavily modified" enough for you, that's fine. Just thought I'd like to show it to you anyway. -Bob

Identify These Pictures!

Okay, I get lots of pictures attached to emails and I end up (after a lot of procrastination) not knowing what picture goes with what message. These are some really interesting photos but I have no attribution for them! Email me with any leads at george---at---sweetmarias.com

Lo-tech convection oven drum

Roasting in a giant SS pot on what I think is a gas grill with bricks to have an even heat transfer to the coffee. Who made this? More pics?

A mystery is solved ... The massive barrel below was build by Scott Jensen! Here is his note of admission, "The big BBQ roaster is mine, as is the large wood-framed cooling tray, set over a box fan. The grill is a Brinkman 4 burner Pro-series 2500. I think it's capable of 42,000 BTU'S. It has four independantly controlled cast burners, which I covered over with ceramic tiles. The drum itself I will have to get back to you on this weekend. I'll measure it and send the specs. It will roast 7lbs, but does it's best, I feel, in the 4.5lb range. Thats where I have the most controll over the roast, I like to try and hit full city in about 17min. Less than 2lbs and over 5lbs I have a much harder time hitting my target. Thanks- thats a neat site! Scott"

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