Whirley Pop Home Coffee Roaster : 13 Steps (with Pictures)

I love my morning coffee, and after mastering my morning routine for grinding beans and brewing (Aeropress), I thought I'd try roasting my own beans.

What I discovered is that with a little bit of effort and a small investment, you can easily create your own custom blend, combining your favorite beans with just the right amount of roast.

This Instructable shows how I made my own roaster setup using a few simple items: a Whirley Pop stovetop popcorn roaster, an electric hot plate, and a windshield wiper motor. The materials cost me about $35, and it's fast and simple to use.

If you haven't roasted beans before, be sure to do it outdoors; roasting beans creates a bunch of chaff and smoke.

Step 1: Find and Modify Your Whirley Pop Popcorn Popper

A Whirley Pop is a stovetop popcorn popper that uses a hand crank to turn the kernels. This is perfect for turning coffee beans while they roast. I bought mine at a garage sale for $7.

I started by cutting off the hand crank and soldering on a ring terminal (from Radio Shack). This is so the motor can turn the shaft of the Whirley Pop.

Step 2: The Whirley Pop Has Arms That Turn the Beans

Here you can see how a Whirley Pop works. The arms on the bottom rotate when the crank handle is turned so that kernels (or coffee beans) keep moving for an even pop (in our case, roast).

Step 3: Here Is the Ring Terminal Soldered Onto the Crankshaft of the Whirley Pop

This was easy to do. If you can't find a ring terminal, see what solutions you can dig out of your spare parts bin.

The key is to make sure the shaft of the Popper can be attached to, and easily disconnected from the shaft of wiper motor when you are roasting beans.

Step 4: Using a Windshield Wiper Motor

Windshield wiper motors are great for home projects; they are super strong and last a long time. I have another one that helps make beer really cold. More on that in another Instructable.

I found this motor online from Monster Guts. It came from a Saturn automobile and cost $19. The power supply is from an IBM Thinkpad and cost $5 on Ebay.

I also bought a piece of 10 inch pine shelving to build a holder for the wiper motor. This is so I can keep the motor stationary and keep the shafts of the popcorn popper and wiper motor at the same height.

Step 5: Using Parts From an Old Desktop PC to Hold the Motor

I used a scrap metal plate from the chassis of an old PC to hold the motor to the wood. The motor is mounted using the three phillips-head bolts shown in the photo.

I also soldered on another ring terminal, just like the one attached to the Whirley Pop crankshaft.

The washers, wing nut and bolt offer an easy way to connect/disconnect the two shafts.

Step 6: Add a Hot Plate, Mount Your Motor Frame

My hot plate came from Target for $9. I plug it in just like the wiper motor, and it heats up really fast.

I also mounted the wiper motor frame onto a piece of pine shelving. Makes it easy to carry the whole roasting setup. The motor frame-mount is moveable, with a knob and T-bolt threaded into a slot in the shelving.

This allows me to slide the motor out of the way when I'm done with a batch of roasted beans.

Step 7: Here's the Power Supply for the Wiper Motor

The power supply plugs into a pigtail adapter that came with the wiper motor. There's no switch; when you connect the power, the motor begins to turn.

Depending on which contact points on the motor you use to connect the pig tail, the motor will go faster, slower or in reverse.

After some quick experimentation, I found the setup that would turn the Whirley arms at just the right speed.

Step 8: Ready to Roast

Here you can see the final roasting setup.

Time to plug in the motor and the hot plate; it will take about 6-8 minutes for the hot plate to reach roasting temperature (maximum); then, it's time to roast.

Step 9: Time to Add the Green Beans

I roast about 1/4 -1/3 of a pound of beans at a time. This is so the rotors on the bottom of the popper can turn the beans without straining.

I buy my green coffee beans online from Sweet Marias; a pound of beans is about $6.50, and the varieties are really interesting to explore.

Once the beans go into the popper, I don't have to do anything except set my timer for 10-12 minutes and work on other projects in the garage.

Roasting times can be faster or slower depending on the temperature outside. The best way to tell when the beans are ready is to listen for a loud cracking sound and observe the color and aroma. After a few tries, you can really dial in your roasting time.

Step 10: Cool Off the Beans When They Are Done

When the beans are done, you need to cool them before storing.

I made a small 'cooling frame' using some spare 2X2 wood and an extra air filter screen from an overhead oven fan. It features a metal flap door so I can easily pour out the beans when they're ready. You could just as easily put them in a muslin bag or a colander and get the same result.

I let the beans sit for about 10 minutes until they are cool enough to transfer.