Wobble Disk Coffee Roaster Looks Good In Wood

If you love coffee, you probably make it yourself at home most of the time using beans from some hipster coffee shop where the employees have full-sleeve tattoos and strong opinions. Maybe you even buy whole beans and grind them right before you use them. If you want to go all the way, you gotta roast those beans yourself. There are various ways to go about it, like repurposing a hot air corn popper. If you’re [Larry Cotton], you buy heaps of green beans and keep building wobble disk roasters until you’ve achieved DIY perfection.

[Larry]’s latest roaster boasts all-wood construction with no metal brackets or housings in the structural parts. This is good because you’re less likely to burn yourself on anything, and you aren’t sinking heat away from the beans. Nothing should get hot except the sifter, the beans, and the stiff triangle of wire that holds the heat gun nozzle in place. Once the roasting cycle is complete, [Larry] just shakes out the beans onto an adjacent screen that’s situated over a fan so they can cool off.

Unlike some of [Larry]’s previous designs, this one uses an 8-cup flour sifter situated over a heat gun. A battery-powered screwdriver drives the wobbling disk that churns the beans and helps them roast evenly, and a wooden arm holds down the power button. We love the simplicity of this machine, and think wobble disk roasters are mesmerizing to watch. Check out the video after the break to see it in action and learn how to build your own.

There’s more than one way to roast beans, and one of them is even officially sanctioned by Hackaday editor [Elliot Williams].

Continue reading “Wobble Disk Coffee Roaster Looks Good In Wood”

How To Cobble A Wobble Disk Roaster Together

As with anything else, once your knowledge of coffee expands, the more attractive it becomes to control as much of the process as possible. Buying whole beans and grinding them at home is one thing, but you’re not a real coffee geek unless you’re buying big bags of green beans and roasting them yourself in small batches.

[Larry Cotton] has made an even more portable version of the wobble disk roaster we saw last summer. Beneath the housing made of aluminium flashing is the guts of a $15 Harbor Freight heat gun pointing upward at a metal strainer. A large metal disk mounted at a 45-degree angle to the spinning axis tosses and turns the beans as they get blasted with heat from below. [Larry] used a 12 VDC motor to run the wobble disk, and an an adapter to change the heat gun from 120 VAC to 12 VDC. This baby roasts 1½ cups of beans to city plus (medium) level in 12-15 minutes. Grab a cup of coffee and check it out after the break.

Roasting beans isn’t rocket science. Even so, there are some things you would benefit from knowing first, so here’s our own [Elliot Williams] on the subject of building DIY roasters.

Continue reading “How To Cobble A Wobble Disk Roaster Together”

Tired Of Popcorn? Roast Coffee Instead

We’ve seen a lot of coffee roaster builds over the years. [Ben Eagan] started his with a hot-air popcorn maker. If you think it is as simple as putting beans in place of the popcorn, think again. You need to have good control of the heat, and that requires some temperature monitoring and a controller — in this case, an Arduino. [Ben’s] video below shows how it all goes together.

With the Arduino and the power supply strapped to the sides, it looks a bit like something out of a bad post-apocalypse movie. But it looks like it gets the job done.

In addition to the Arduino, a thermocouple measures the temperature and that takes a little circuitry in the form of a MAX31855. There’s also a relay to turn the heater on and off. There are other ways to control AC power, of course, and if a relay offends your sensibilities you can always opt for a solid state one.

Continue reading “Tired Of Popcorn? Roast Coffee Instead”

Wobble Disk Coffee Roaster Gets The Beans Just Right

Coffee roasting is an art or a science, depending on who you talk to. Both camps will however agree that attention to detail is key. Many diehard beanheads, as they’re known, will go so far as to create their own roasting hardware to get the job done just right. [Larry Cotton] is one such builder, who has created an elegant roaster to get his brew just right.

The build is based around a wobble disk design. This consists of a round plate fixed at a 45-degree angle to a rotating shaft. As the shaft spins, the disk gently sweeps and agitates the roast, allowing the batch to heat up evenly without burning the beans. It’s a two-part design, with heat gun parts in the base to generate the hot air for the roasting process. The bean basket sits on top, held in place by magnets that also act as a conduit for the wobble disk motor’s power supply.

It’s a tidy build, which allows for accurate roasting and easy dumping of the beans once finished. If you’re a serious beanhead yourself with a few hacks up your sleeve, be sure to let us know! Video after the break.

Continue reading “Wobble Disk Coffee Roaster Gets The Beans Just Right”

Build An Excellent Coffee Roaster With A Satisfyingly Low Price Tag

There’s a lot of mysticism around coffee roasting, but in the end it couldn’t be simpler. Take a bunch of beans, heat them up evenly, and stop before they get burned. The rest is details.

And the same goes for coffee roasters. The most primitive roasting technique involves stirring the beans in a pan or wok to keep them from scorching on the bottom. This works great, but it doesn’t scale. Industrial drum roasters heat a rotating drum with ridges on the inside like a cement mixer to keep the beans in constant motion while they pass over a gas fire. Fluidized-bed roasters use a strong stream of heated air to whirl the beans around while roasting them evenly. But the bottom line is that a coffee roaster needs to agitate the beans over a controllable heat source so that they roast as evenly as possible.

My DIY coffee roaster gave up the ghost a few days ago and I immediately ordered the essential replacement part, a hot air popcorn popper, to avert a true crisis: no coffee! While I was rebuilding, I thought I’d take some pictures and share what I know about the subject. So if you’re interested in roasting coffee, making a popcorn popper into a roaster, or even just taking an inside look at a thoroughly value-engineered kitchen machine, read on!

Continue reading “Build An Excellent Coffee Roaster With A Satisfyingly Low Price Tag”

DIY Coffee Roaster Uses Cordless Drills And A Camp Stove

We’re no stranger to coffee roasting hacks, but it’s been a while since we’ve seen a new DIY roaster design. Thankfully [Larry] has been hacking together a small-batch roaster with a bunch of off-the-shelf parts. He was originally trying to make a fully-automated roasting system, but after a bunch of failed prototypes, he settled on a simple roaster design that works great.

[Larry]’s roaster is designed for small batches of coffee (about 3oz). He has a small hopper with a motorized auger (cannibalized from a chocolate fountain) which drops coffee down into his roasting basket. The basket is mounted to a cordless screwdriver which rotates it to agitate the beans inside. A small camp stove provides the heat, which is placed right under the basket. The beans churn around in the roasting basket and heat up until they reach the desired roast level (typically between first and second crack).

Once the roasting is complete, another hand drill rotates the basket assembly to dump out the coffee. [Larry]’s build includes an assortment of knobs and switches which control the auger, basket speed, bean dumping, and even a “speedometer” gauge that shows how fast the basket is rotating. Want to build your own roaster? Check out the instructions for building [Larry]’s roaster or some other builds we’ve featured before.

Fabricating Custom Displays For A Commercial Coffee Roaster

custom-display-panel-for-a-coffee-roaster

Roasting the perfect coffee bean is an art form. But even the most talented of roasters can use a little feedback on what’s going on with their equipment. [Ludzinc] recently helped out a friend of his by building this set of 7-segment displays to show what’s happening with this coffee roaster.

The yellow modules hiding underneath the display panel are responsible for setting the speed of the hot air blower and the rate at which the drum turns. They’re adjustable using some trimpots, but it sounds like the stock machine doesn’t give any type of speed feedback other than direct observation.

The solution was to patch into those speed controllers using the ADC of a PIC chip. They each output 0-10V, which [Ludzinc] measures via a voltage divider. After the speed is quantified the microcontroller outputs to one of the displays. Since there’s a different chip for each readout, the firmware can be custom tuned to suit the operator’s needs.

Keep this in mind if you’re still planning to build that coffee roaster out of a washing machine.