A Rough Outline for Building the “EZ Wobble Disk Coffee Roaster”
An alternative to buying a purpose-built home coffee roasterA machine for roasting coffee. Or the person operating it! The basic requirements for a coffee roaster are a heating element that gets suitably hot and a mechanism..., or using a popcorn popper or an oven to roast, is to build your own machine.
And nobody captures the DIY spirit of home coffee roasting
The application of heat to green coffee seeds (beans) to create palatable material for brewing a great cup!: Coffee roasting is a chemical process induced by heat, by... better than Larry Cotton. He’s been a customer and comrade for years, always sharing his new designs to encourage others. From using flour sifters for a roast chamber, Larry came up with a unique and effective design for moving coffee and roasting evenly. He calls it the “wobble disk,” and he’s able to roast a good volume of coffee using this scheme.
Here’s the intro to Larry’s document, and the PDF file you can download with a direct link at the bottom of this page. – Thompson
PDF Intro by Larry: Have you ever craved a cup of coffee brewed from beans you roasted? In a roaster you built? That sports a wobbling disk, an 8-cup flour sifter, most of a 13″ pizza pan and three red tubes? Yes?
Well, here’s your chance to build one! Roasting times of 12-20 minutes are typical for 300+g (~11 oz) of green (raw) beans in ambient temps of 40+F and above, depending on your likes. Unlike most commercial roasters, you can roast back-to-back batches with no cooling pauses.
In the building process you’ll sacrifice the flat part of the pizza pan*–well seasoned or brand new–to yield most of the roaster’s metal parts.
Though it’s nowhere near as sophisticated and feature-rich as commercial machines (think $$, technical savvy and space requirements), I guarantee it will yield many amazing cups of very fresh coffee.
This plan specifies the materials and tools needed to build the roaster. Depending on your workshop and materials on hand, costs should be around $100-$150.
Warnings: Both building and using this coffee roaster require tools, parts and procedures that can injure you if safety is ignored. A heat gun (normally used for stripping paint and such), and the sifter surrounding its nozzle, can reach 450+ deg. F. This roaster must be used outdoors or in a building or garage with an open door. Coffee beans can emit smoke near the end of a dark roast, and will catch fire if left unattended. And the hard-working wobble disk that stirs the beans could injure you if you touch it while roasting.
I highly recommend using the main parts as specified; they’ve been thoroughly tested in more than a few home-built roasters I’ve built over the years:
Larry’s PDF Outline to Build this Coffee Roaster:
You can view the file in a browser below, and click Download at the bottom of the viewer to save it!
3 Responses
I’d say don’t skimp on the heat gun quality and invest in a better brand. The cheap plastics/heat element coil material in low tier disposable heat guns would be far from trustworthy applying heat to a consumable product. Not to mention pathetic temperature control/consistency being used for lengthy periods of time.
I’ve built 24 of these roasters over the years, all of which take the Harbor Freight Warrior heat gun. Yes, it’s cheap and has only 2 settings: hot/slow and hotter/faster. None has failed except the one that wasn’t mounted correctly–my bad! If you spend more money you can get more control, for sure, especially the ability to run the fan with no heat; that would be great for the cool-down cycle! I have to dump my beans immediately to cool.
Larry Cotton
That is so beautiful. I loved seeing how complete all the instructions are and that there are pictures of everything that might be confusing. I feel like I already built the roaster. Thank you so much for the fine set of instructions. I did have to laugh at the suggestion that a cardboard box would be helpful in wind protection when roasting at the beach. At the beach? I think that, as a heathen, I would roast my beans before going to the beach. Thank you for the best read I have had in a long time. I love how clear and thorough you are.