Step 1: Materials.
- A 3/8" construction rod which was getting rusted in my backyard (2 meter long).
- A piece of aluminum pipe where the rod will fit loose (for the crank). To be honest, I'm not too good at aluminum sizes, so just look
at the pictures please.
- Two tuna cans.
- A scrap stainless steel sheet that was left from another project (30 Cm X 20 Cm).
- A couple of washers.
- A short piece of thick wire about 1/8".
Step 2: Making the Roaster Body.
For the tuna cans to fit inside the crank and actually get cranked, we need to make some 3/8" holes right at the center of them, and with a small triangular file or a 1/8" file, make an off centered hole like the ones you see on the pictures. You will understand what I mean when you see the crank. (Sorry if the pictures are not very clear, but you can make out the holes).
Once your holes are made, your roaster is ready fit the two tuna cans on each side of the rolled sheet to make a can with two caps. Now let's continue with the stand and the crank.
Step 3: Making the Stand.
Note: Make sure you measure the total length of the roaster before bending the rod, so that it will fit with a little slack between the two hooks.
Step 4: Making the Crank.
After you have made the crank bend, at 7 cm, make another bend to fit the aluminum pipe, giving yourself enough room to freely grab the crank. I measured the pipe by grabbing it with my fist and leaving an inch on each side. Make yet another small bend for the pipe to stay in place.
Once your crank is bent, go to a close shop and have the two pieces of wire welded only at the center, not on the outside, because you want them to be a little shaky in order to absorb some of the pressure from the crank on the cans (look at the pictures to see where they are welded). On the last picture, you can see the washers in place without the roaster.
Note: The distance between the center rod and the crank should not exceed 7 cm, otherwise your hand will be hitting against wherever the roaster is standing. Trust your eye-balling abilities here, just like I did when I was bending the rod for the stand. Remember your rod is only 2 meters long. Before you weld the short wire that is close to the crank, insert one washer that has a 3/8" hole that will hold the roaster in place once it is all assembled for roasting. If you forget this step, you can always cut the washer and insert it later like I did, but it will look better if it is uncut.
Step 5: Assembling the Roaster.
Step 6: Roasting Coffee.
First turn on the heat in high for about 3-4 minutes and then lower it to medium. In my experience at roasting coffee, I have noticed you get a richer coffee flavor when you roast it at medium heat. Crank constantly until you start listening to the beans crack. Your coffee is almost ready. At this point you see smoke coming out of the roaster. Continue cranking until the smoke is more continuous and at this point turn off the heat. Remove from the stove using your crank handle, remove the upper tuna can using a pot holder and turn your beans in a container to cool off as quickly as possible. Your coffee beans are roasted.
Note: Before you use your roaster for the first time, it is a good idea to put it on the stove for at least 15-20 minutes and crank it a couple of times to burn any toxic materials coating the inside of the tuna cans, usually plastic, which might be toxic.
Here's a useful link to help you learn a little more about roasting coffee. http://www.youtube.com/watch?v=d3ZA5Eg9wfg
I hope this project helps all the people out there who like good coffee and who enjoy doing things themselves. Oh! and have a cup of good coffee on my name.