Using a handheld fan to control heat during a popcorn roast

[c0alJK]

Rating the roasts is not something I would do...as I really consider my lack of experience to be the limiting factor. I can however tell you there was a vast improvement from using it just as is without being able to control the heat, to fitting the dimming circuit. We had numerous very drinkable batches, and some that my wife even liked, or preferred to what the local roaster supplied. Could probably have been better if someone with more experience did it, but it wasn't bad. If by "woody smell" you mean burnt smell, nope, that was not a problem for us.

Just to show how really quick and dirty it can be done, here's what I did. I fitted the dimmer into an extension lead box (happened to have one handy), and plugged the popper into that. You can also see where I cut the tracks to power the fan directly.

second pic shows where I fitted the thermocouple. Arguable how good a location it is, but it works. I didn't want something in the way of the beans that I was going to knock all the time while agitating.

Cheers!

Looking good, doing something very similar real soon. Thanks for sharing!

[jannus]

Cheers for the info, do you find that you could produce some excellent quality roast? How would you rate it /10?

How about the woody smell, do you notice any of that still?

Rating the roasts is not something I would do...as I really consider my lack of experience to be the limiting factor. I can however tell you there was a vast improvement from using it just as is without being able to control the heat, to fitting the dimming circuit. We had numerous very drinkable batches, and some that my wife even liked, or preferred to what the local roaster supplied. Could probably have been better if someone with more experience did it, but it wasn't bad. If by "woody smell" you mean burnt smell, nope, that was not a problem for us.

Just to show how really quick and dirty it can be done, here's what I did. I fitted the dimmer into an extension lead box (happened to have one handy), and plugged the popper into that. You can also see where I cut the tracks to power the fan directly.

second pic shows where I fitted the thermocouple. Arguable how good a location it is, but it works. I didn't want something in the way of the beans that I was going to knock all the time while agitating.

Cheers!

[stralto]

I would never bother going back to roasting in a popper without being able to control the input voltage.

I'm using a Breville Crazy Popper connected to a $35 Variable Fan Speed Controller.

No special wiring required and it provides excellent control of temperature. Of course, at lower temperatures you also get lower fan speed which results in insufficient motion and agitation of the beans. This is easily overcome by stirring for the first three minutes.

From 0C to 150C I have a small desk fan blowing over the top of the unit to reduce the ramp up temperature.

When it hits about 150C (Fan Speed controller on high-medium setting) the beans are lighter (and fan is faster) so the beans move/mix freely by themselves. From here on in I can control the temperature quite precisely (hold it within a couple of degrees), all the way up to 235C (max temp is dependent on other factors too).

I roast 100 - 120g at a time and extend the roast as long as I want

The de-coupling method jannus posted above would be an additional improvement - but i don't have the know how to do that type of wiring.

[c0alJK]

Running a popcorn maker as is I found to be way too hot and way too quick. It would get to 1C then 2C really really quick, almost uncontrollable. Using the dimmer and the fan wired as I did, you can turn down the heat as much as you want, and find a good rate. Even if you're flying relatively blind, there's a lot more control, and you can get some decent roasts from it. Of course at the end you can do a very nice cool down phase right there by just turning the heat back and letting the fan carry on. The biggest disadvantage is the small volume you have to work with.

Cheers for the info, do you find that you could produce some excellent quality roast? How would you rate it /10?

How about the woody smell, do you notice any of that still?

[jannus]

It seems 60g is the sweet spot, will have to try that next. Glad yours can get you 15 mins roast, I struggle to reach that time before burning it - it's happened once haha. And yes, I hate that woody smell so much, but you are right i'm noticing it fades away slightly after >5 days. I have a good feeling it's cause of the rapid heat of the popper. I'm really hoping I can get some level of complexity when I get to adjust the heat, but stock as is now tastes unbearably bad... really flat and acidic.

Agreed about the blends too, I haven't done home blends but the best shop ones I've tried only had maximum of 3 beans. Also I'm in the same position as you, came very close to just buying a behmor to skip all this frustration but deciding on a better roaster in the long term so i'm saving up. Really banking on the mod to get me some decent roasts at least to get by now :/

Running a popcorn maker as is I found to be way too hot and way too quick. It would get to 1C then 2C really really quick, almost uncontrollable. Using the dimmer and the fan wired as I did, you can turn down the heat as much as you want, and find a good rate. Even if you're flying relatively blind, there's a lot more control, and you can get some decent roasts from it. Of course at the end you can do a very nice cool down phase right there by just turning the heat back and letting the fan carry on. The biggest disadvantage is the small volume you have to work with.

[jannus]

I just bought the exact same dimmer for about $12, just waiting for it in the mail! I think that's the best way to wire it, variable fan would be nice but priority is the dimmer. What brand temp probes? And how did you hook yours up? :/

I used a K-type thermocouple I ended up getting from a local hobby shop, was dirt cheap. Probably not ideal, but it works well.

I hooked that up to an arduino, and ended up adding a solid state relay as well, so the fan ran full speed (if it ran slower the beans probably wouldn't move anycase), and the SSR / temp probe combo controlled the rate from Artisan with Artisan doing the PID. It was pretty responsive. There's so much air moving around, I used it only as a drum temp kind of sensor, never tried to get meaningful BT readings.

Cheers!

[c0alJK]

So far with no mods, the Sunbeam popper with 60g of beans runs OK - takes approx 15min to 20min to get a darker roast. I also bought a Breville roaster from JB which is more powerful, and I have to reduce times by about 3 mins for it. I run both popcorn roasters at the same time and get 120g batches, often mixing the results of the two machines into resealable plastic bags and labelling them with my Brother 12mm tape labeller. The temps using my laser measuring device seem around 180C +- 20C which I don't think is too hot and seem to be the minimum temperature for proper roasting - much hotter and better than my cast iron roasting attempts which were 160C or so and I was probably getting underdeveloped baked coffee instead of roasts.

With these popcorn makers, I was initially getting underdeveloped, woody expresso blends but have found that by resting the beans at least a week and blending with just two beans I am getting much better results. For example a 60% El Salvador + 40% Brazil tasted surprisingly complex and good -giving me hope.

I was previously blending 4 beans trying to get the right recipe. Then I tried a coffee at a Williamstown coffee shop and was astounded at how good the coffee was so bought 250g of their beans, only to find out it was a simple 50% Brazil 50% Columbian. That inspired me to simplify my blends. Yesterday I had an expresso from a local cafe which was 100% Brazil and it had plenty of complexity.

I have been thinking about getting a Behmor coffee roaster now that they are in stock but read a few blogs and posts about the need for hacks and custom roast profiles etc, tin foil tricks etc. which has put me off.

It seems 60g is the sweet spot, will have to try that next. Glad yours can get you 15 mins roast, I struggle to reach that time before burning it - it's happened once haha. And yes, I hate that woody smell so much, but you are right i'm noticing it fades away slightly after >5 days. I have a good feeling it's cause of the rapid heat of the popper. I'm really hoping I can get some level of complexity when I get to adjust the heat, but stock as is now tastes unbearably bad... really flat and acidic.

Agreed about the blends too, I haven't done home blends but the best shop ones I've tried only had maximum of 3 beans. Also I'm in the same position as you, came very close to just buying a behmor to skip all this frustration but deciding on a better roaster in the long term so i'm saving up. Really banking on the mod to get me some decent roasts at least to get by now :/

[c0alJK]

I just bought the exact same dimmer for about $12, just waiting for it in the mail! I think that's the best way to wire it, variable fan would be nice but priority is the dimmer. What brand temp probes? And how did you hook yours up?

[tcab]

So far with no mods, the Sunbeam popper with 60g of beans runs OK - takes approx 15min to 20min to get a darker roast. I also bought a Breville roaster from JB which is more powerful, and I have to reduce times by about 3 mins for it. I run both popcorn roasters at the same time and get 120g batches, often mixing the results of the two machines into resealable plastic bags and labelling them with my Brother 12mm tape labeller. The temps using my laser measuring device seem around 180C +- 20C which I don't think is too hot and seem to be the minimum temperature for proper roasting - much hotter and better than my cast iron roasting attempts which were 160C or so and I was probably getting underdeveloped baked coffee instead of roasts.

With these popcorn makers, I was initially getting underdeveloped, woody expresso blends but have found that by resting the beans at least a week and blending with just two beans I am getting much better results. For example a 60% El Salvador + 40% Brazil tasted surprisingly complex and good - giving me hope.

I was previously blending 4 beans trying to get the right recipe. Then I tried a coffee at a Williamstown coffee shop and was astounded at how good the coffee was so bought 250g of their beans, only to find out it was a simple 50% Brazil 50% Columbian. That inspired me to simplify my blends. Yesterday I had an expresso from a local cafe which was 100% Brazil and it had plenty of complexity.

I have been thinking about getting a Behmor coffee roaster now that they are in stock but read a few blogs and posts about the need for hacks and custom roast profiles etc, tin foil tricks etc. which has put me off.

[jannus]

Not sure why my popper is like this but with 1st crack so soon, my roasts taste so very dry and underdeveloped I can definitely tell they're undercooked inside with a bit of uneven roast (80-100g batches, I have tried 120g but it gets even more uneven). Currently looking at ways to delay 1st crack without switching it on/off, and am now about to experiment using dimmers/potentiometers - as my last resort, didn't want to mess with electrics in the first place. Did you have the same experience?

Just from my side - I found it easiest to disconnect the internal fan and run that off an external 24V DC powersupply - so that always ran full speed. Then I ran the popper (essentially just the heater circuit) on a 2kw dimmer I got from a local dealer for dirt cheap. That gave quite some control of the roasting power. Add to that a temp probe, and you can get some pretty good control.

I found that mine worked best on 55g, and even then I'd agitate by hand until close to 1C. Anything more than that gave very uneven roasts.

Good luck! It's a bit messy with the chaff going everywhere, but for such small batches it's manageable with a small broom afterwards...

Best regards

[c0alJK]

How did you go? I recently started getting into roasting with the same Sunbeam popcorn popper and I find with this popper (this is the only one i've used) my temps are way too high, the power on this thing is too much. I wouldn't need to remove the thermostat like others do, in fact I need to turn the power down, way down. I'm getting 1st crack at about 3-5mins, roasting outside at 16c ambient (at night) with a fan on high directly at the popper + a 15m extension cord.

Not sure why my popper is like this but with 1st crack so soon, my roasts taste so very dry and underdeveloped I can definitely tell they're undercooked inside with a bit of uneven roast (80-100g batches, I have tried 120g but it gets even more uneven). Currently looking at ways to delay 1st crack without switching it on/off, and am now about to experiment using dimmers/potentiometers - as my last resort, didn't want to mess with electrics in the first place. Did you have the same experience?

[deegee]

G'day tcab, No - I have never tried roasting in a pan or skillet.

One downside of using poppers is their capacity. Stock units can usually only handle 60 to 80 grams of green beans in warm weather, and maybe 80 to 100 when it's colder. It can get a bit tedious if you need to do large quantities in such small batches.

I mostly use a modified popper as it gives me fast response to changes, and very good control. It can handle up to 150 grams (greeen) but I usually do a bit less. I mostly do 125 gram single origin batches and blend post roast. Because I mainly roast just for myself, this is not a problem. For the occasional larger roast I have a Behmor.

You may find that the thermostat in your popper is attached to the heater coil plate, not the chamber. If it is, don't try to move it, those mica plates are very brittle and quite fragile. The solution is to short out the thermostat by soldering a wire across it, or carefully bend the contacts together, so they cannot open, no matter how hot they are.

In this pic the t'stat is the widget between B and D.
If you haven't already seen it, take a look at this thread - it's a bit dated now, but most of the info is still valid.
https://coffeesnobs.com.au/forum/cof...ps-tricks-mods
Cheers, deegee.

[tcab]

wirecutter23 thanks for the advice! I will follow it and move the thermostat.
I suspect the steps are probably very similar to those in this youtube video, which I watched some time ago.

[wirecutter23]

Also from my experience I reckon it's an absolute must to move the thermostat inside the popper. If you don't, there's a high chance that the popper will cut out due to the high temp during your roast and ruin your batch.

I think moving the thermostat in the Sunbeam one is pretty straight forward. You just have to remove the case (undo screws on the bottom) and unbolt the thermostat from the side of the popping chamber (you can see where it's attached if you look into the popping chamber - you'll see a dot on the side). Just move it to a place wheer it won't heat up too much and you shouldn't have any problems. No re-wiring needed! Good luck.

[wirecutter23]

tcab,

I started roasting with a cast iron skillet before moving to a popper (i'm now using a coretto set up). II got my popper to the point where I could produce a much more consistent roast than with the skillet. But every now and then now i'll roast a batch on the skillet because it's a lot of fun and sometimes its refreshing to roast a batch based on feel and not a formula!

Personally I think it comes down to how easy you want roasting coffee at home to be. Getting your popper set up right with all sorts of mods can mean it can be pretty hands-off which might or might not appeal to you.