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comment by PacoH
PacoH  ·  3501 days ago  ·  link  ·    ·  parent  ·  post: Home Roasting Part II: Modifying the Air Popper to Extend Roast

Hey ecib, this is a great post. That popper is ubiquitous and is one of the few currently available for cheap that meet the side-vent requirement for coffee roasting. The annotated images are first rate. I am glad that you advocate simply moving the thermostat as opposed to removing it like so many people have done over at the Sweet Maria's forum. That practice is dangerous. I can envision relocating it to just the right position where it cuts off so you don't get too fast a roast but your roasting times are long compared to mine. I am using some old generic brand popper I picked up at Goodwill and it gets very hot without any modification. My roast times are too short. I am thinking about actually adding a thermostat because it doesn't have one. Just the opposite of your dilemma.

Though there are a lot of tangent posts about the uhhh… 'coffee culture' here in USofA, they are amusing. Only Americans make such a big deal about making good coffee. And the various coffee forums are the worst offenders. All kinds of snobs, forum bullies, and disseminators of misinformation abound on those sites. Not to say that there isn't some good solid information there, it's just that the signal is buried deeply in the noise. It seems that everyone is engaged in a really infantile competition at being THE master 'barista' in this country. I have to laugh at all this. I went to Italy in the 70s and I was blown away at what Italians simply consider coffee. We call it espresso, they call it simply caffè. We make a big deal about it. They take it for granted. We pay $4 for a shot. They now pay $1. Christ, they've been quietly enjoying superb quality coffee for a century and a half while, at that time we were still using percolators with the reject coffee that Juan Valdez supplied us with. :) When I came back I immediately sought out the coffee shops in the Italian neighborhood. The coffee was good, just not AS good. In Italy you can find good coffee even in little bars in remote train stations in small towns. It's ingrained in the culture. And a barista is just a bartender who knows how to make great caffè, mix drinks, and grill sandwiches. No big deal is made of the craft. We are gastronomical infants by comparison. Enough said…





ecib  ·  3501 days ago  ·  link  ·  

Thanks, though re-reading it I just noticed that step 9 really didn't need to be there, haha. And yeah, bad idea to remove the thermostat imho. At least located on the bottom, there is a chance it could trip if the temp gets catastrophically hot.

I'm with you on some of the absurdity of coffee culture here, -all you need is some fresh roasted good beans and a fresh grind and you're basically all the way there. Nobody percolates anymore, so pretty much any way you brew it will be fine, but a simple press is going to kick ass.

I will say that the $4 dollar cups of coffee I have here at good shops are significatly better than what I grew up on. At least I'm getting something for my money, and prices are only ever going to go up :)

Regarding your short roasts, did you try using a really long extension cord and/or roasting fewer beans at a time? I know it sucks to roast with fewer beans in a popper because the capacity is so small to begin with you usually want to get as many in there as possible, but more beans = less air flow = hotter quicker. I often hand-shake my unit while roasting in order to extend the roast.

PacoH  ·  3500 days ago  ·  link  ·  

Yeah… no I would never use a long cord to reduce the voltage/current. That's a little too much of a kludge for an engineer like myself. Total waste of power. What I WOULD do is add a simple SCR/voltage regulator with a pot to smoothly regulate the voltage to the main coil. I was thinking of splicing in a frying pan probe thermostat but the SCR is the way to go.

I agree with you on the simplicity of obtaining superior coffee at home for cheap. I pay $8/lb for top quality varietal beans and I roast 3 small batches at a time. This lasts me and my wife about a week, drinking one cup a day, and I get many weeks out of just one pound.

I long ago determined that I can only roast 1/3 cup of beans at a time with my machine. That way it starts whirling immediately without stirring. If you have to stir to get things going, you're being too impatient and should reduce the load IMO.

As for percolators, I was only using that as an example of what was the norm at that time. I got a Macchina Mocha Espresso stovetop filter-up pressure pot when I was in Italy. It's what everybody there used at home. So I was enjoying superior espresso even back then while most Americans never had a cup of espresso. Then came the Melitta filter and then the coffee machines that used the paper filter and the rest is history.

I use an Aeropress for everyday use and a La Pavoni Pub for when I want to spend some time crafting a REAL cup of caffè.

ecib  ·  3500 days ago  ·  link  ·  

Ah, I use and Aeropress too. Since I've been roasting, I've become a bit more particular, but my wife persists in only liking dark roasts from two brands...Starbucks Verona or Trader Joe's French roasts. Neither one I can drink black. So I have to make two different cups each time I make us coffee, and it's just easier to brew with a single cup brewer like an Aeropress. That it is almost impossible to screw up the brew with one is an added bonus.

    What I WOULD do is add a simple SCR/voltage regulator with a pot to smoothly regulate the voltage to the main coil. I was thinking of splicing in a frying pan probe thermostat but the SCR is the way to go.

Oh man, if you do this post pictures!

PacoH  ·  3484 days ago  ·  link  ·  

Here's an update. After considering all of the cheap SCR controller boards on eBay, I decided that it would be more involved than I had hoped because I would have to buy and populate an enclosure, since the boards were all too big to fit inside the popper housing, and then there was the heat dissipation problem. The much discussed Harbor Freight Router Speed Control had all the qualities I needed. And it was on sale for $19.99 and with the 20% OFF coupon it cost just $17.40 with the tax. What's great about it is it is a self-contained unit so there's nothing to build. It worked actually better than I had anticipated. I had read in the beer-making forums that people had to add a massive heatsink to the aluminum back-plate of the case, some even going so far as to mill a depression in the plate to better fit the heatsink. The first time I used it, I set the VAR control on maximum until first crack, about two minutes. It did get hot enough that I could only touch the back-plate with two fingers for two seconds. When I turned it down so the beans were barely swirling around, it was warm, not hot. The next time I put the switch on FULL until first crack and then switched over to VAR and turned it down until the beans were just barely swirling. This time the back-plate was barely warm the whole duration. So great, no need for a heatsink. I have to say that, even though the control also reduces the fan speed, the roast is slowed down enough so that it is much more controllable and much more even. So this is already a huge improvement. Phase one completed.

Next I have to come up with a way to control the fan independently, using a minimalist, read that cheap and compact, approach. I'd prefer to have everything inside rather than have an external box with a separate wire. I'll report back on what I find.

ecib  ·  3473 days ago  ·  link  ·  

Thanks for the update! Sounds like the modification was definitely a success. I hadn't actually seen that particular speed control before, but it looks like a pretty clean solution. How long did it take you to do the mod would you say?

PacoH  ·  3465 days ago  ·  link  ·  

There are numerous forum posts about this controller. People use it for controlling popcorn coffee roasters, beer brew kettle heating elements, even high power industrial lighting for video production, saving thousands of dollars off commercial controllers.

Here are two excellent posts about using it for coffee roasting:

Ultimate Poppery II and Pumper - Home Roasting

Hacking the Orville Redenbacher Hot Air Popper to Roast Coffee

Heh-heh, the 'mod', if you can call it that, took me as long as it took to go to the store, buy the unit, then go back there and exchange it because the one I got looked used. That's it. Just plug 'er in and go. :)

After using it several times, I decided the chip, which is a BTA26-600B A320 Triac, is getting too hot. This was designed to provide intermittent power to a router, not continuous power to a heating element. Even though I can replace this chip for $2 on eBay, I never want to overdrive a component like that so I decided to add a heatsink like the guys that use this for controlling heating elements for beer brewing and controlling industrial lighting. Mr P's 110v Harbor Freight controller duel element setup has a nice discussion about this. Here is a photo of his mod:

The heatsink will cost me more than a replacement chip and some work but I like to do things right the first time whenever I have the luxury of doing so. ;)

I decided there's no practical way to separate out the motor circuit and drive it internally so I will just slap a jack onto the shell and use a nice little 32V 750mA plug-in power supply from my trashed HP Piece-O-Crap® printer. That way I can use it on any popper.

PacoH  ·  3425 days ago  ·  link  ·  

OK, I finally got the heatsink from China and did the mod. I did an Instructable on it.

Harbor Freight Router Speed Control Mod

ecib  ·  3388 days ago  ·  link  ·  

Woah, just saw this. How has it been performing for you? That looks awesome!

PacoH  ·  3367 days ago  ·  link  ·  

It works well. Even at full power with the Variable setting, the heatsink is barely warm. I still have to do the fan mod though because it slows the fan.

PacoH  ·  3500 days ago  ·  link  ·  

Starbucks and Trader Joe's? OK, I've bought Starbucks beans and had them grind them to my specs for the Aeropress when I was visiting in NYC. It was not that bad. They still can roast better than I can but they don't have anything approaching varietal coffees. I used to buy only Trader Joe's Dark Sumatra. But now that I have discovered roasting, I have never looked back.

For the Aeropress, I use one rounded scoop of unground beans for one cup. I grind them to between espresso and French press. I steep for one minute, using the plunger to keep the coffee in the tube. I even did an Instructable Make Great Coffee with an Alternative to the Aeropress 'Inversion' Method and a video about it An Alternative to the Aeropress 'Inversion' Method. There are tons of videos on the inversion method so naturally, I got some flack and down-votes from that crowd but who cares? They are exactly the ones I was talking about above. Infantile little fanboys who think their clumsy over-thought method is best.

My wife uses a Vietnamese filter coffee strainer with my roasted beans.

Don't worry, if/when I do the SCR mod I will make an Instructable on it. I have not seen that done anywhere.