Author Topic: Fluid bed roaster  (Read 634 times)

Gime2much

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Fluid bed roaster
« on: April 03, 2011, 05:24:05 PM »
I had forgotten just how nimble an air popper was until finding an original Poppery 1 at the thrift store for $3 last week. After split wiring it and disabling the safety thermostat, I threw in 4oz of El Salador Bourbon and pulled off a very even 12 minute roast thanks to variac control of the element. Amazing how quickly the rate of heat rise reacts to adjustment of the variac compared to the UFO/CO.

 I started out on poppers and there are a few things, like having an unobstructed view of the beans, that no other type  roaster offers. Dam the fact that poppers are limited to 1/4 lb or so.

Dan

randytsuch

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Re: Fluid bed roaster
« Reply #1 on: April 03, 2011, 08:37:12 PM »
You can add a boost transformer, and increase capacity a little.

I think my transformer adds about 15 volts, and there is a noticable increase in fan speed.

I haven't used my pumper for a while, but the ability to boost and change the fan speed gives you real time adjustments that I can't do with a drum type roaster.

Randy

Offline sontondaman

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Re: Fluid bed roaster
« Reply #2 on: April 04, 2011, 08:49:03 AM »
I have successfully roasted about 200 grams in my poppery 1 just by splitting the heat and the fan circuit. At the beginning  I have to tilt the roaster a bit for better agitation but as roast progress, the beans becomes lighter and will agitate better. I also add the glass chimney to prevent rogue beans from popping outside.

Gime2much

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Re: Fluid bed roaster
« Reply #3 on: April 04, 2011, 11:34:31 AM »
 The 1500w heat element of the Poppery 1 should handle as much as 1000g but the airflow is always going to be an issue. I actually wish for more capacity than the 1 lb for the UFO/CO and 3/4 for the Behmor. I'm working on a CO setup that can roast a full kilo but with 20 projects going at the same time (ADHD?) not many of them see completion.

 The air popper is great for trying a small batch of new beans so it will probably remain as is. It's certainly fun to revisit ones roots from time to time.

Offline rasqual

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Re: Fluid bed roaster
« Reply #4 on: April 05, 2011, 06:46:02 AM »
Yah, my typical batch is 10 oz in a Wearever 1400W model. That's not a challenge -- it's the sweet spot. I use a Corning bread tube for the chamber (the 3" ones are rare on e-bay nowadays), and of course tilt it substantially. To obtain large batch sizes, it seems necessary to partially obstruct the downward flow of beans (near the bottom of the chamber) to prevent compression. I can't imagine such a batch size without doing that.

I also variac the fan -- not the heater. A boost to the fan allows dense greens to flow early in the roast, and reducing the fan later when agitation increases due to decreased density keeps the heat up. With the proper tilt to the apparatus, manual profile control is a cinch.

I'm about to build my 2.0 model, which I suspect I'll do a bit differently. Hope to eliminate the variac and contrive a better means of securing the chamber.

Note:the ceramic element was an interesting experiment; I no longer use it. For now.



(geez, I sure hope that was a DP. Not a very consistent roast!)