I picked up a Nostalgia Electrics Mini popcorn popper from Kijiji the other day, and although it had the features to look for (deep chamber, side air vents, no mesh bottom), it's significantly lower power (1040 Watts) than the much vaunted West Bend Poppery. Also, probably cheaper construction, the thing felt lighter than my pound of green beans. I've read that most poppers get too hot, but I've also read that some of these newer models are underpowered. I was surprised at just how fast it went!

Parameters:
- 50 g Ethiopian Yirgacheffe from a local roastery (I figured I'd start experimenting with small batches)
- Outside in -2 C weather with a brisk wind
- Plastic hood removed from popcorn popper

Results:
- First crack started at 1:06, lasted until 2:13
- Second crack started at 3:00 and I stopped the roast at 4:00

I figured I'd run it past second crack just to experience the whole process.

For my second attempt, I did everything the same but this time I shook the whole popcorn maker more or less continuously to introduce more airflow. I managed to delay first crack by 30 seconds, and it still lasted for about a minute. I stopped the roast just as second crack was starting at 4:15, because I like lighter roasts. The result is a bit lighter and a bit more even.

Today, I tasted both batches in espresso form (I will try aeropressing as well, but I was too excited). The taste was reminiscent of a time I tried eating a raw olive off a tree in Spain... really one of the worst things I've ever tasted, and with a lingering aftertaste that ruined even my next real coffee. Yes, they've rested for less than 24 hours, but I don't really have high hopes.

Questions
- Is it possible that I never actually hit second crack, but that there was a weirdly long pause in the middle of first? The beans do not look as dark as I would expect from going to the end of second crack (also, they're very uneven). If this is the case, would I record it as first crack lasting for 3 minutes?

- Is there anything I can do to slow things down while I work on a more advanced control system? The long extension cord idea makes me cringe, but I was thinking of drilling some holes in the plastic casing to introduce more airflow. I was also under the impression that smaller batches can help, but I don't think I can go much smaller than 50 g.

Ultimately, I know this is not the best way to do things. I'm thinking of building an Arduino control system, as I'm somewhat familiar with Arduino and it sounds like fun. However, it'd be nice if I could get some decent results with the unmodified machine if only to prove to myself that this is a worthwhile project.

Generally at 2nd crack you will have some hollow beans from the insides exploding. I don't actually see any in the pic. But yeah, if you are hitting 1c that fast, then it will taste terrible. Also, you would slow the roast by adding more beans, not less. But then you will likely have issues with your fan, but you can try putting in more beans and stirring throughout the roast if you don't mind doing that. Stirring will also help with the evenness.

The quickest and cheapest solution to do better roasting, for around $35 you can put put variac on heating element, dimmer switch on fan, and thermometer in the beans. Plenty of guides out there on how to do that. That said, if you are already pining for arduino, then that will likely be $35 wasted. That said, that said, arduino can get a little pricey, unless you already have the stuff. If you decide you don't like roasting, then the variac route would have saved you money. It's a risk either way really, you just have to choose.

Once you have temp control, then good starting point is to hit 300f bean temp in 4-5 minutes, 1c in the next 4-5 minutes, and learn to adjust temps to keep the bean temp rising during the roast and not stalling out. Do that and in a short time you will have better coffee than any pre-roasted coffee you can buy costing twice as much. Then just work out from there to figure what you like best.

Hmm, so maybe some of my beans are hitting 1st at 1 minute, some at 3, and I'm not really going to 2nd. That would explain the unevenness/paleness.

For some reason I thought that fewer beans in a popper slowed it down by allowing more airflow. However, I watched some of the Sweet Maria's videos and my beans definitely weren't dancing around as much as theirs were. I'll play with batch size, though I'm wondering if I might also have a weak fan. I don't mind stirring - probably better than the shaking I was doing for the second roast!

I thought about the variac thing, but they're a bit more expensive in Canada. I had a similar thought progression though... if I'm spending $50 already, might as well get a temperature controller, but if I do that, might as well just get an Arduino and program the PID myself, and that way it'll be useful for other projects if this one doesn't work (or if I move on to bigger and better roasters!). I've also got Arduinos at work that I could probably borrow, though I'd still need to buy some components.

On the totally opposite end of the price spectrum, is there any reason I shouldn't use this 2000W SCR Voltage Regulator in place of the Variac?

Charbucks,

I'm new to roasting myself. After a lot of consideration, I decided on the Heat Gun & Bread Machine route. I wanted to roast larger batches (8 to 12 oz) and also a bit more control. I started with the heat gun and a dog bowl, but quickly moved to the bread machine for stirring. It provides a very even roast, since the bread pan is vertical, keeping beans huddled together, and is stirred constantly by the machine. Another advantage for you, being in Canada, is that the bread machine is probably better insulated and should perform better in cold weather. I've roasted outdoors in freezing weather and have gotten great results. You could buy a more powerful heat gun to help counteract the cold weather.

I'm very happy with my results to date. The heat gun allows for a lot of control. If you mount the gun in the top of the bread machine, you will probably want a gun with adjustable heat levels (I'm using a Wagner HT3500, purchased at Home Depot). If you hand hold the heat gun, you can raise and lower it to control the heat, so you might be fine with a single power on/off gun, probably about 1500 watts or so.

My typical roast goes as follows:

4-5 minutes from start to 300F (drying phase)
4-5 minutes more to First Crack (usually 380-400F, depending on the beans)
2-3 minutes development to end of roast
Total time: 10 to 13 minutes typically

I know this doesn't speak directly to your current mode of operation with the air popcorn popper. So, if this approach doesn't interest you, just ignore it. I'm thrilled with the results I am getting.

Lou

An easy thing to try is a really long extension cord(s). For example, a 50' cord should slow the roast considerably. I recall plugging several cords end to end to get the time I wanted. That said,I have never liked the taste of coffee roasted in a popcorn popper no matter what I tried
The constant blast of air seems to impart a very harsh, dry taste that gets worse as the coffee rests.
The whirley pop style of roasting tastes a lot smoother, in my opinion. But it has its quirks and challenges too.

Thanks for the replies. It's beginning to sound like an unmodded popcorn maker really isn't capable of much, which I suppose is to be expected - I'm just surprised that others seem to have gotten anything drinkable at all from them.

My reasoning for going the air popper route was the low barrier to entry. I am willing to entertain the idea of spending more, but I'd like to prove to myself (and my husband!) that this is a worthwhile venture. I do have a whirly pop, but I use it all the time for popcorn. I might be able to borrow a heat gun for a while though, and they're not as expensive as I thought, so that might be an option. They're also useful for other things, so if I ultimately give up the coffee roasting it's not just a sunk cost.

For now, I might just hardwire the fan on the popcorn popper directly to the power cord and operate the heater as a bang-bang controller. Might as well destroy this thing if I'm going to be moving to new methods!

Charbucks,

It can be done inexpensively. I bought a used bread machine at a thrift store for $6. Heat gun was $39 at Home Depot. Digital temperature meter on Amazon was $20 and a type K thermocouple probe was an extra $10-15. Total cost was about $80US. It took a little work to set it up, but nothing that difficult. Contact me via personal message if you want the details on the above items.

That's a pretty low cost of entry. Since green coffee beans are typically half the cost of roasted beans, sometimes less, it pays for itself quickly. My home roasts are better than what I was buying, even fresh roasted stuff. I've only been doing this for about 3 months, so once you get the basics down, it is pretty easy.

I thought about the Whirly Pop and almost went that route. Some people get great results with it. I guess I chose the heat gun and bread machine because I thought it would be easier and that my roasts would be more even.

Good luck. It's worth doing if you like roasting your own. If you don't want to be bothered roasting once or twice a week, it's probably better to find a good source or fresh, pre-roasted coffee. I like doing it, so for me it is a Win - Win.

I used an air popper when I was first starting out, and was eventually able to get fairly tasty roasts out of it.

I left the fan wired in directly with no dimmer, but wired in a high-wattage dimmer switch to the heating element. There are good guides on homeroasters.org about how to do that mod. I also used sugru to permantly attach a thermocouple probe to the top lid, which was set to be centered in the middle of the bean mass during a roast.

If you keep a hand on the dimmer switch and keep an eye on the rate-of-rise (the speed of temperature increase in the bean mass), you can go as fast or as slow as you like using a setup like this. Fluid bed roasts will tend to taste a bit brighter and dryer, in my experience, but they can still be pretty good.

With all that being said, a HG/BM roaster is far more versatile, and will do much larger batches so that you can spend less time roasting and more time enjoying the coffee. But it is more work to build, so if you are in a hurry to improve your roasting you might want to try the dimmer switch mod on your popper to last until you've finished setting one up.

Alright, I just bought a high voltage dimmer switch off of Ebay. Should arrive by the end of March :p. I may well have switched systems by then, but it's still something I want to try.

Ibdina: $80 is quite a bit more than $5, but I get what you're saying. I already have a multimeter with a temperature probe, so it'd really only be the heat gun. Might be able to justify that one even if I do abandon the coffee roasting venture, or move on to a proper roaster.

As an aside, I'm jealous of the green coffee prices in the US. With shipping it seems next to impossible to find green beans in smaller quantities (~5 pounds) for under $10 a pound in Canada.

If you already have a multimeter and temp probe, and can find a bread machine cheap at a thrift store, you can use a very inexpensive, single power, single speed heat gun if you choose to hand hold it. Just vary the distance from the surface of the beans to control the temp and rate of rise. Agreed...$80 isn't $5.

Some people just use a heat gun with a stainless steel bowl instead of the bread machine. Cheaper yet. Lots of videos on YouTube.

Best of luck.

Lou