My problem with home-made roasters thus far has been a pretty severe and handicapping one - I have absolutely no electrical skills and the very thought of making electrical mods causes me to break out in a sweat. This pretty much eliminates most of the standard accepted methods of roasting here. So, I have for better or worse come to use the soup can roaster over coleman propane tanks (the heat from the stovetop was simply not hot enough, or so I thought).

In theory, this method seems to offer all the heat control one would need, and my roasts have been markedly improved using this method since leaving behind the unmodded popper or the unmodded bread machine and "scorch" gun. But it is lacking in many areas. Here are the problems I can see with this method:

1. Monitoring the temperature is an issue as a thermocouple cant really be installed in a unit such as this and infrared thermometers seem to be unreliable from what I have read
2. As the soup can is solid, a hole is needed to pull samples to observe the progress of the roast, however, this seems to allow too much heat loss.
3. The drum itself I suspect needs to be able to retain more heat.
4. The mechanism for controlling the drum speed (the drill trigger) needs a fabrication of some sort to offer more reliable control.

Can anyone offer suggestions on how to improve this setup (even if they are extravagant - at least it will point me in the right direction)? Or, do you think that this method is usable at all?

Since you can't see inside, or easily record bean temperature, you need to go to plan B: the roasting technology of a hundred years ago:

Insulate the roaster as much as you can:
-- Buy a cheap aluminum pot with lid, drill holes or cutouts in the sides for the axle, and mount the drum inside.
-- Make a fiberglass insulation tea cozy for the pot lid and sides.

Now keep the environmental temperatures as low as possible: Add a cheap $10 TC to measure the air inside the pot. Preheat it so the air is around 400F, and let the temperature rise slowly to around 475F over the course of the roast.

Now roast by cracks. Pull it as the first fades for a light roast, first pops of the second for a medium one, and top of the second for a dark one.

Now tune your profile: Adjust the amount you roast so that the roasts finish in 12 to 14 minutes or so, regardless of roast depth, in that 400F to 475F pot. With experience, you can tweak the temperature profile of your pot air sensor, for instance, you can bring up the pot temperature to 500F for faster roasts of high density beans, or drop it for slower roasts of Brazils or island coffees. You can also tweak the initial temperature (the drop in) to affect the drying and timing to first crack. You may also want to let the pot temperature peak at the first crack and drop it afterwards to get a slower finish

I don't know if this will work. But it's how people used to roast before high tech controls were easily available, and it's not a Rube Goldberg solution.

Oh boy... I am truly sorry for wasting your time by asking such an airheaded question, but... if I mount the drum to the inside of an aluminum pot, how is it supposed to rotate?

Thank you very much for a highly do-able improvement with tips!

The outside of this roaster would look like a stock pot with a crank.

Sounds like a stovetop popcorn popper.

Why reinvent the wheel? Here's a link to a Freshroast, which I'm sure you can find elsewhere for less with a little bit of searching: http://www.sweetmarias.com/prod.freshroast.php

Then, find a generic Variac which you ought to be able to pick up for around $30. No electrical skills are necessary, you just plug the roaster into the Variac, and you turn the dial to reduce the voltage to extend the roast where you want to extend it, especially as you approach the onset of 1st crack, and then until you terminate the roast.

Alternatively, you could find another sort of cheap air roaster, such as a popcorn popper, and use that.

You can easily snake a cheap thermocouple/digital thermometer wire into the roasting chamber to enable you to monitor the roast. The last time I checked, cheap digital thermometers with included thermocouples cost around $12.

ken

Thanks! I guess that is quite a bit easier than I gathered. So, what are the major drawbacks to a popper/variac style roaster other than batch size? (BTW, I have never roasted more than 1/2 cup of green beans at a time anyway, so this wont be at all bothorsome). And is there any reason that I should get a specific air device (eg the Poppery I), or rather are there other upgrades that will come down the road that a specific model will make easier to facilitate?

Also, any issues with doing back to back roasts with any of the poppers, or the FR?

noah wrote:Thanks! I guess that is quite a bit easier than I gathered. So, what are the major drawbacks to a popper/variac style roaster other than batch size? (BTW, I have never roasted more than 1/2 cup of green beans at a time anyway, so this wont be at all bothorsome). And is there any reason that I should get a specific air device (eg the Poppery I), or rather are there other upgrades that will come down the road that a specific model will make easier to facilitate?

Also, any issues with doing back to back roasts with any of the poppers, or the FR?

One very nice thing about air roasters (which includes poppers) is that you get to see and hear what is going on with the roast, close up, and in your face! After doing a couple of batches you will get a good general idea about the stages that occur when you roast coffee, and this is very useful no matter what kind of roaster you end up using longterm.

It's been a while since I've used a Freshroast. There used to be issues with the base cracking, especially if it got too hot, however I'm sure that has been fixed by now. If you were going to get a FR, I'd buy a second roasting chamber (not that expensive, $18-$20 each, and available separately) which would allow you to let one of the chambers cool while you use the other one, e.g. to alternate them.

Before buying a FR, I'd do a little research on this type of roaster, as I haven't kept up with them and I don't know what else is out there that might be better. There are some other ones that have larger capacity and that cost more, but you'd need to look into that too (see Sweet Maria's link below).

As to poppers, there are some that are safe to use for home coffee roasting, and those that can catch on fire. Sweet Maria's explains this here in detail, as well as the other air roasting options that they sell: http://www.sweetmarias.com/instructions.php

There are people who have done very exotic things with poppers; Jim S. immediately comes to mind. You can certainly go all out and start rewiring them, but I think that you will be fine just getting a Variac, and using the voltage adjustments to get the controllability that you want. There are different kinds of Variacs at different prices. I'm sure that someone here can point you to a good source at a cheap price. I bought mine ages ago for $20 or $30.

As to digital thermometers and thermocouples for monitoring roast temperatures, there are a lot of cheap ones out there, and most or all of them will be accurate enough for your purposes. You should probably buy your roasting device first and play around with it for a while before you start trying to monitor temps, using the cracks as your roasting guide. When you do look for a digital thermometer and thermocouple, you will need to be sure that you can get the probe into a place in the roaster that will give you consistent information about how your roasts are progressing. Good luck.

ken

Well, variacs are not quite straightfoward, at least on ebay. Jim, I read your review of a 5 amp variac on coffeegeek, which you stated was sufficient at that time, do you still think that 5 amps is sufficient, say, for a Poppery I? (or II, I suppose) Also, any issues with buying Chinese made? Ken, I know you said generic will do, but will it do for a unit whose amperage is technically too low?

Plus, any general buying advice or sources that anyone can offer would be of great assistance to this blind buyer!

I'm no longer an expert on variacs; especially not the cheap ones on Ebay.

My take on your questions, no offense, is that you are not much of a DIY person. I would either recommend getting something that works off the shelf, like a Hottop or Gene, or even the Iroast if they've overcome their QC problems. If you really wnat to get into DIY, putting in the effort to understand and build your own PID kit, i.e. PID, SSR and sensor, is a better time investment then messing with variacs.