Even though there are a few machines on the market dedicated to roasting coffee in small amounts, home coffee roasting inspires the do-it-yourself spirit in many of us and has sent many Sweet Maria's customers down the path of creating their own roasting machines, most of which seem to work very well. Here's a few of them, described in words of the designers/builders themselves. Hey home roaster manufacturers, take some notes!
Karl Schultheisz's Flour Sifter/Heat Gun Roaster
Not an original design. Been using it weekly since November 2014 for 120g batches. Full sensory experience (via open flour sifter chamber) is very educational. I have considered adding a temperature controller to keep performance more consistent in outdoor temperature extremes. All components are multi-use.
Kyle Klobucar's Tin Can Roaster
"I put it together because I wanted more control and repeatability than the air popper I was using and I couldn't commit to buying an expensive home roaster. I also hoped to increase my batch size a bit, which it did (151g charge works great so I can get 3 roasts out of every 1# green with almost no odd leftovers).
Drum - steel Ikea utensil caddy. It has a centered hole drilled through the bottom so it rotates pretty evenly. Lined with mesh. I used tin snips to make simple aluminum fins (3). They are mounted with short bolts facing outward to try to avoid stuck beans during roasting (I've never had a problem with that yet). I started with them angled but ended up straightening 2 of the 3 out as the beans tended to sit a little too far to the rear. I cut a tin lid so it would snap over the open face, then cut a hole in it for airflow and probe placement.
Drum motor - old cordless drill. It's bottom heavy and stable. I used a threaded rod with nuts and washers at the drum end and put it right in the chuck at the other. I use a c-clamp thing to hold down the trigger, which is variable, so I can set my drum speed to where I want.
Body - I don't know what to call the tin can. Basically, I couldn't get the drum hot enough with a heat gun, so I cut up these big tin cans to fit around it. It'll go past 2C no problem now, but for me that just means I have more control at and around 1C. The two pieces pull apart so I can grab the drill, pull out the drum, and dump the beans. I cut a strip of aluminum and bent it up to hold a thermocouple probe to get BT. I don't know how accurate it is (1C is almost always at 400F), but the numbers are repeatable, so that's huge for me. I was planning on making a stand to hold it in place at the right angle, but it wasn't necessary, and I was more interested in roasting than fabricating."
Tije de Jong and Frans Goddijn's Shanken-Not-Stirred Roaster
The following text is copied from this Dutch website that has more info and videos of this roaster that takes a different approach to coffee roasting.
Tije let go of the idea to agitate the beans by a powerful air flow and he also discarded the "rolling drum" concept which has been used in most classic roasters so far. He tried stirring the beans but found that this hard to do automatically. He used the motion of a jigsaw to shake a kitchen sieve filled with beans and he took the heat from a simple paint stripper
Neil Friesen's Modified West Bend Poppery
Flipping the power switch turns on the fan. The little dial on the bottom left side controls the voltage going to the heating element. The bottom display is a voltage display of what the dial is doing. The top display is temperature in Celsius from a Thermo couple placed just below the plastic chimney of the popper. These two things in tandem allow me to be very precise if I want to get repeat results from a roast. I currently only roast 110g at a time. The purpose of the extended chimney is so that when I roast in winter I can do it inside. I attach a flexible dryer vent into a bowl so I don't have a large mess to clean up later.
Pat Mitchell's Motorized Popcorn Popper Roaster
This is a modified sweet and easy snack machine from Wabash Valley Farms. I got tired of turning the handle, so I cut it off, attached it to a robotics motor and ran that motor to a controller to manage the right speed. I've roasted over 100 batches of coffee with this roaster and it works great. I can roast anything from a couple of ounces to a full pound. However, I find the sweet spot is right at a half pound. I use an electric hot plate so that I don't have to worry about propane tanks. I also added a second wire stirrer inside the machine. Next steps on this will will to add an internal thermometer and then set that up with logging software. However, it works fantastic based on my needs.
Want to see a few more hod rod roasters? CLICK HERE and check out our archive of DIY roasting machines built by our customers.