Print PDF
Favorite
Email
Step 2Making the popcorn machine into a coffee roaster
Popcorn machines are simple devices that consist of a fan that blows air past a heating coil. The heated air is blown through holes into an aluminium tin where is causes a vortex. Beans or popcorn in the tin will be heated by the hot air and dance by the vortex in something that is called a fluidized bed.
I started with this link, but I found out that my popcorn machine didn't roast the beans. It hardly popped popcorn. Then I found out it didn't heat above 180C (that's probably why it was only 10 euros).
I opened the roaster and bypassed the heating security (as I didn't take any pictures during the making of the coffee roaster, you need to check the site below for details on bypassing the security). Without this security, your roaster could go to higher temperature than it is supposed to, which could result in fire. So be smart. I noticed this already when the see-through polycarbonate cap started to meld. Therefore I replace it with a food tin, with bottom and top removed.
With the security bypassed, the popcorn machine could heat up to higher temperature, but still not high enough. Then I came across this website and followed the advice to disconnect the fan and the heating coil and make the fan speed control-able. As I don't understand too much of electronics, it took me a while to find out how to do this (the dimmer mentioned on the site cannot work, as far as I know). The motor in my popcorn machine requires 20V and uses about 0.8A. You can't simply reduce the voltage as the motor will not have enough power to keep on going at lower voltage. Instead you will need a pulse-width modulator. I got a DC motor speed regulator (Kemo electronic B71) for 20 euro, which I needed to put together myself, but worked perfectly. As a power source, I use the adapter of my laptop (19V 3.4A).
Disconnecting the coil and fan allows you to turn of the coil at the end and cool your beans with the fan at max, which is also great compared to cooling the hot beans in a colander.
Next, you need a good thermometer! Mine is a cooking thermometer, going up to 300C. You could do without, but you will not be able to follow a temperature profile and it will be difficult to repeat your results as the outside temperature is of great influence to the temperature in the roaster. Mine cost me 40 euro, which I realize is a lot of money. But with this, your coffee roaster will be much more advanced than the commercial roasters you can buy for 200 euro's, which doesn't measure temperature, only time.
Drill a hole through the popcorn machine and into the aluminium tin and place the temperature sensor about 1 cm above the bottom of the tin.
I started with this link, but I found out that my popcorn machine didn't roast the beans. It hardly popped popcorn. Then I found out it didn't heat above 180C (that's probably why it was only 10 euros).
I opened the roaster and bypassed the heating security (as I didn't take any pictures during the making of the coffee roaster, you need to check the site below for details on bypassing the security). Without this security, your roaster could go to higher temperature than it is supposed to, which could result in fire. So be smart. I noticed this already when the see-through polycarbonate cap started to meld. Therefore I replace it with a food tin, with bottom and top removed.
With the security bypassed, the popcorn machine could heat up to higher temperature, but still not high enough. Then I came across this website and followed the advice to disconnect the fan and the heating coil and make the fan speed control-able. As I don't understand too much of electronics, it took me a while to find out how to do this (the dimmer mentioned on the site cannot work, as far as I know). The motor in my popcorn machine requires 20V and uses about 0.8A. You can't simply reduce the voltage as the motor will not have enough power to keep on going at lower voltage. Instead you will need a pulse-width modulator. I got a DC motor speed regulator (Kemo electronic B71) for 20 euro, which I needed to put together myself, but worked perfectly. As a power source, I use the adapter of my laptop (19V 3.4A).
Disconnecting the coil and fan allows you to turn of the coil at the end and cool your beans with the fan at max, which is also great compared to cooling the hot beans in a colander.
Next, you need a good thermometer! Mine is a cooking thermometer, going up to 300C. You could do without, but you will not be able to follow a temperature profile and it will be difficult to repeat your results as the outside temperature is of great influence to the temperature in the roaster. Mine cost me 40 euro, which I realize is a lot of money. But with this, your coffee roaster will be much more advanced than the commercial roasters you can buy for 200 euro's, which doesn't measure temperature, only time.
Drill a hole through the popcorn machine and into the aluminium tin and place the temperature sensor about 1 cm above the bottom of the tin.
| « Previous Step | Download PDFView All Steps | Next Step » |
 |
Add Comment
|
