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JackH
OfflineAdmin
· 08/10/2020 8:46 PM
Had to make myself another cup of coffee to get through it.

snwcmpr
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· 08/10/2020 7:33 PM
I went into withdrawal for a bit. Now .. all is good. roar

mtbizzle
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· 08/10/2020 7:26 PM
Yeah Jack I think so, I couldn't access for a bit

JackH
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· 08/10/2020 6:51 PM
Did we lose the site for a while?

JackH
OfflineAdmin
· 08/06/2020 3:33 PM
Allenb, how are you doing?

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Noob build - never roasted anything, diving in
shortyjacobs
So I've never roasted a single bean before. But I wanna. I mainly drink espresso, though thinking about getting back into pourovers/press as well. I've got 4 lbs on the way from sweetmarias. I don't feel like dicking around with a popcorn machine when I know I'll want more control pretty much instantly.

Goals:
Fluidized bed hot air
Electric
250ish g batches,
Good temp control.

My plan: 2kw 220v element, run off of a PID with manual mode, (but no ramp/soak or programs). Ducted fan (1st choice) or vacuum cleaner motor, (2nd choice, cuz I don't have one on hand). either metal or pyrex cylindrical roast chamber.

Questions: What's more important, BT or ET? Should I control my PID off a RTD probe in the beans, or hot air?

I love the look of the asymmetric roast chamber in this video: https://www.youtube.com/watch?v=FtmH4...tmH4mUB9bk...thinking of using the bake-a-round pyrex cylinder - will that work with 250g batches? Or what should I do on roast chamber?

Oh, and are there tips on how to seal the pyrex/metal RC to the tube below? RTV sealant? 100% silicone caulk? some type of silicone gasket?

Chaff collection - I'll be using an exhaust hood to suck up the smoke - don't want to clog the fan with chaff.....screen to catch chaff? vortex chamber? Other?

My reasons for some of the choices above are cost. I want to start CHEAP here - make sure I like home roasting. I am a (former) homebrewer (no time with kids), so I already have fused/GFCIed 220V and 110V (30A and 20A, respectively) power going into a control box with RTD PT100 probe hookups, twin PIDs, SSRs, a variable speed exhaust hood that goes outside. darn thing even has an E-Stop. My plan is to keep this under $20 until I know I'm happy home roasting. So far I'm in for $8 for the 2KW heat gun element, $7 for another RTD probe, and $4 for an extra XLR connector to hook the probe into my control unit. Fan unit is scavenged from my garage, as will be everything else I need, with luck.

Thanks!
 
allenb
Hi Shorty,

A couple of thoughts on sensors and control. If you're set on only measuring one spot in your roaster you've got to make it bean temperature since without BT you're flying blind and can't hope to dial in profiles and will never be able to repeat them. The danger in running an electric roaster without seeing the temperature leaving the heating element is element burnout if you happen to hit too high of an element temp for more than a few seconds. If you're not planning on ramp/soak control or automatic profile following then there's no need for PID since you won't be setting any single setpoints for your ET to hold to. Go full manual control with variac or TC4 into an SSR. With the TC4 you'll have a place to plug two thermocouples into for reading ET and BT.

If you must stick with your $20 budget then go propane with a used campstove burner and use a bimetalic dial thermometer dropped into the roast chamber.

No problem roasting 250 gram batches in a 3.5" diameter bake-a-round.

Be prepared for many close calls if using the glass RC as it's not easy to avoid dropping if you have a removable RC. If I built another fluidbed I'd use sheet metal to avoid the skipped heartbeats when trying to dive for it before it rolls off the table.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
shortyjacobs
Hi Allen,

Thanks for the advice.

For control - I can measure multiple points. I have a pair of PIDs in my control unit I can use, (even just use for temp readouts), as well as a multimeter that can take a K-type thermocouple. So I can measure up to 3 points. In the future I'm thinking TC4, or other custom arduino option, or just the $80 auber PID with ramp/soak...but right now the two PIDs I currently have don't support ramp/soak/profiles, just setpoints.

So you're saying there's no point in putting a single setpoint for ET or BT and modifying it as roast progresses? (i.e., set BT setpoint at 200F, wait a few minutes, go to 210, then 220, then 230...basically manual ramp/soak). My current PIDs do have manual/automatic bumpless transfer, so I can go into full manual mode at the touch of a button and dial the heater from 0-100% at will.

So BT is the most important temp for monitoring roast progression - but if I'm doing a "manual control" ramp/soak - do I want to control the PID with BT, or ET?

Yeah, my first attempts will most likely be metal RCs because they are cheaper/free (cobbled together from spare parts around the house). My concern was that I'd have trouble knowing what was going on without a visual. I'll be roasting in my basement, with my exhaust hood directly over the exhaust of the roast chamber....so it'll be tough to see in from the top. (My exhaust hood is more of a "trunk", it's the part above the keg in this fuzzy pic:
i.imgur.com/8MI8E.jpg)
)
 
allenb
Sounds like your well equipped for being able to measure both BT and ET. I've tried resetting the PID controller's setpoint variable every few seconds and never had good luck with it as it would go to full power and back to minimum with a yo-yo effect with each new setpoint. Definitely go the % output mode for manual control and you'll be set! In fact, I would stay with that for quite a while to get to know your roaster before attempting automation.

On controlling ET or BT with manual control? You'll find best results by controlling power based off of bean temperature rate of rise. By doing this you can smoothly follow a predetermined profile by knowing in advance temp rise in degrees per minute needed. You can do mental calculations by watching the degrees tick off / minute or better yet, get yourself a TC4 and see the value in realtime which is what I and many others are doing now.

On using a metal RC. Cut a vertical slot down the side of the RC and silicone in a 1" wide strip of glass for a viewing window. Doesn't need to be real tall but just enough to be able to see spout height.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
oldgearhead
I've been roasting for over three years now with my home-built, 120 volt, electric, one-pound, heat-reclaiming, fluid-bed roaster. I do NOT use PID temperature control. I set the desired air temperature at the start of each roast and control the roast with the blower control. Most 440 gram batches of Central and South American, wet-processed, green beans are roasted for 12 minutes with 500°F air temperature using constant 1075 watts. I use a temperature controller that has manual (%) control of the SSR pulses.

I cannot envision roasting inside anything but a glass vessel. The sight, smell, and sound are all important to my roasting experience.

__ Blower = Two-stage, flow through, VC.
__ Heat = One 1550 watt heat gun element usually running at 1Kw.
__ Roasting Chamber = One Pyrex Bread Tube.
__ Cooling = In the RC
__ Chaff collection = In the RC
__ Evac = 'J' tube

http://forum.homeroasters.org/forum/v...ad_id=2207
oldgearhead attached the following image:
bmt_1_8.jpg

Edited by oldgearhead on 09/25/2014 8:24 AM
 
shortyjacobs
Thanks OGH and Allen,

You're answering a lot of my questions. Great tip on the sight glass in a metal RC - and it answers another of my questions - can I use 100% silicone caulk in the "hot" areas. Answer is clearly "yes"!

OGH - the all-glass RC is definitely an attractive option....I think pretty soon here I'll be staking out bake-a-round auctions on fleabay....though I may start with all metal just for prototyping purposes...

Any opinions on the asymmetric roast chamber spout in my original post? (the youtube video). Seems like an advantage over symmetrical center spout is easier to tweak while maintaining good mixing. Disadvantage is it's tougher to initially build. Thoughts?

Thanks!
Keith
 
allenb
I've never worried about what type of silicone adhesive I used. After thorough drying and after it's been cured in 400 F air for 15 + minutes it'll be safer than the interior of your car any day.

On comparing asymmetric versus conical RC bottoms, you will be very happy with either as both will produce excellent coffee. The asymmetric takes a little less blower pressure to achieve bean lift compared to conical.

To me, a big advantage of the asymmetric is the simplicity of construction. For the sloped RC bottom and perf plate, cut a piece of sheet metal into an oval shape, cut off part of the oval, screw the cut end onto a round disc with holes cut at the right spot to coincide with the space left between the cut off end of the oval and the outside of the round RC tube. Silicone the works into the bottom of the RC tube. This also eliminates experimenting with various kitchen and bar coned shape appliances to find the right cone wall slope. Make the metal RC tube heavy enough so you can simply set it over the air exit hole of the roaster base and if you have a precision enough fit between RC bottom and roaster base surface then you won't even need a gasket. Maybe just include a couple of angle brackets strategically located to act as guides to center the RC on the base. I fabricated an asymmetric RC bottom including holes in two hours total fab time.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
allenb
If you end up going with an asymmetric, here's some perf hole layout numbers I put together from Rob's build notes:

http://forum.homeroasters.org/forum/v...post_40101

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
oldgearhead
For me it's all about re-purposing. I've found the 3.5 inch stainless-steel cocktail shaker top perfect for any size load from 120-550 grams in my Bake-A-Round, and I didn't need to fabricate anything.

The shaker top with it's nineteen 0.150 inch holes delivers a nice center spout every time..
oldgearhead attached the following image:
dsc_5397_6.jpg
 
allenb
To help Keith in his quest for picking an RC design, it would probably be a big help to describe for him how you made the transition from heating element tube/shroud to the inlet of the shaker cone, how the shaker cone attaches to the underside of the top of your roaster base and how you attached the bakearound to your base for your permanent/fixed RC. This would give him a good idea of fabrication needs and tools required using a shaker cone and fixed bakearound RC.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
oldgearhead
The entire project and bill-of-materials is still here:

http://forum.homeroasters.org/forum/v...ad_id=2207
.
Allen the shaker top isn't fastened to the RC. The RC simply sets on top of it.The shaker top 'locates' it's seat inside the bottom RC flange.
.
oldgearhead attached the following image:
dsc_8347_7.jpg

Edited by oldgearhead on 09/26/2014 10:03 AM
 
allenb
Thanks for posting the link to your build which will give Keith a good look at all of your fabrication steps that were necessary to pull all the parts together. I'm still amazed at how well your roaster turned out and especially the "elegance" factor of the way the RC chamber turned out.

BTW, have you come up with a painless method of removing baked on film inside of the bakearound?

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
shortyjacobs
Allen, OGH, you guys are fantastic. OGH I'm about a third of the way through your build thread, I'm very impressed! I can see why I keep reading, "I copied OGH's design" in so many build threads... The heating chamber made out of sink plumbing - fantastic. I've been trying to figure out what I'd use for that.

So I see why you guys love vacuum cleaners so much. I figured I could do it a lot quieter if I took a large fan, ducted it, and funneled it down to a reasonable outlet. I spent an hour or two today building a duct for my fan out of wood, 1/8" clearance between the fan and the ducting, and funneled it from 8" to 1". I know, fans, (like normal whirly propeller fans), are low pressure, high volume, but I figured by ducting and dropping the outlet size, it'd work!

It didn't work. You all knew that, I'm sure, but know I've demonstrated it for myself. I was amazed that even just the funnel, which had a 1" outlet and ZERO restrictions, basically had no air come out of it. The fan by itself could blow stuff 10 feet away, but slap the funnel on it and air was just dribbling out of a 1" hole. Time to tear apart a vacuum cleaner. I have a monster upright unit we no longer use - I'm guessing that's gonna be way too powerful....the motor is 12 amp.

Allen, glad to see I'm not out in left field with the asymmetric thing. I'd only seen one youtube vid of it. The pictures and calculations in that thread are great! I think I'm going to start on this route - I don't have a cocktail shaker I can cannibalize, and I'd rather make a RC bottom for free than spend $20 on a shaker at Target. I can't argue with how "polished" OGH's setup looks though!

You folks in this forum really have stuff figured out.
Keith
 
shortyjacobs
Well might as well make this in to a build thread while I am at it. Found what looked like a decent deal on craigslist. $20 for this: http://www.grainger.com/product/DAYTO...cuum-6H003 Bag was busted up a bit, but otherwise in decent, albeit dirty, condition. Went, looked, picked it up for asking price, (too much of a hurry today to haggle, and the guy was really nice). Brought it home, and was too excited to take pics before diving into it. Ripped it apart, gave it a pretty thorough cleaning, attached it to a triac dimmer I had lying around, and fired it up. Even on low it might be a bit too powerful, but time will tell - to be honest I have NO idea how much power I need to loft 250-400g beans. It's a 6A motor running on 120V.

lh3.googleusercontent.com/-BrIHC0IwsP8/VCch7_YF7AI/AAAAAAAANb8/OntZBCMFO20/w756-h567-no/20140927_154254.jpg

lh4.googleusercontent.com/-uvJWfg37w2g/VCch96N6hcI/AAAAAAAANcI/rYQ6eD2t6_I/w756-h567-no/20140927_154317.jpg

lh5.googleusercontent.com/-qE3MZV9Ds8g/VCciAIPsIEI/AAAAAAAANcU/IPq4NXfHsA0/w756-h567-no/20140927_154342.jpg
 
shortyjacobs
Hmph, so much for a build thread. Anyway, I encased the blower motor pictured above in a big box. I then went through a few iterations trying to SEAL that darn box....got it mostly there. Controlling the motor speed with a SCR speed controller.

Used a sink drain to mate a steel/chrome downtube to the box, put the heater gun element into that tube, and stuck in a K-type thermocouple to get "ET".

Ended up going with the Target shaker after all. On top of that is a progresso soup can which has been torched to return it to solid steel, (to extend the RC), and the rest of the shaker on top of THAT. All held together by a couple of springs.

The K-Type thermocouple is read by my multimeter, sitting on top of the fan box. The 2KW 220V element is controlled by one of the PIDs in my brewery control panel, (it actually comes in at around 2.2KW thanks to my 240V). An RTD temp probe pokes into the RC from the bottom (height adjustable), to measure BT - that reads out on the PID. A squirrel cage exhaust fan blows the hot air out the dryer vent.

I did a test run today - no beans, just an empty RC. Ran it up to 525F air temp to burn off anything nasty left over.

It'll be interesting to see how it controls. The shortest duty cycle the PID will do is 2 seconds - that's pretty darn long for a heater element. It was glowing pretty red in there - not sure how red it can get before it blows.

I'll have to do a bit more work before I can roast - the duct tape holding together the exhaust system worked great when I was brewing 10 gal batches down there, but apparently 500F is a bit hot for the glue, and it started to fall apart. I'm not doing any chaff collection - hoping it just blows out the dryer vent. We shall see.

Click picture below for a bigger version!

lh5.googleusercontent.com/-CwjqgE7WSOo/VE1zEP94O8I/AAAAAAAAOKk/B1w4TytLMWk/w756-h567-no/20141026_171704.jpg
-Keith
 
shortyjacobs
Slowwww going. Got around to building a new roast chamber....realized with the fully opaque one I'd never know what airflow i'd need to get a nice spout, (can't easily see into the metal one, it's so tall and narrow I'd have to put my face right in the airflow, and it's hot).

Still haven't roasted anything in it, but fun to build! woohoo

Didn't break any new ground here. A bake-a-round, some metal, some allthread. Not as fancy as OGHs, but I don't have the tools or friends he does :-).

lh6.googleusercontent.com/-jL-GrqFriL0/VFb7TwqEHRI/AAAAAAAAOMg/SSZFKeCXLjc/w425-h567-no/20141102_214846.jpg
-Keith
 
oldgearhead

Quote

allenb wrote:

>put the snip<
BTW, have you come up with a painless method of removing baked on film inside of the bakearound?
Allen

Allen.
Every 4 months I put the Bake-A-Round, 'O' rings, and the flanges into a sink full of dish-washing suds and scrub everything. Really there isn't too much 'film' to deal with. Only a 5 inch band around the top. I tend to use mostly wet-processed beans so cleaning the 'inards' is kept to a minimum.
 
shortyjacobs
It's alive!

lh3.googleusercontent.com/-es1x00z2bnA/VFwliyWJxAI/AAAAAAAAOOs/rA53HGefm5E/w822-h616-no/20141106_195044.jpg

Roasted my first batch today. Warmed up the system a bit, got all my stuff ready, notepad, timer, calmed and prepared myself, and dropped the beans.

Temp skyrocketed up to 250F BT, I freaked out and dropped the element down to 20%. Meanwhile my exhaust fan was doing diddly squat to collect the chaff, so I ran upstairs and grabbed a metal strainer to throw overtop to collect all the crap flying out. Trying to take notes, but it was all happening so fast! BT dropped...DROPPED....to 150F, I cranked it back up, got on a nice ROR path, (Best as I could tell looking at the thermocouple readout and guestimating), and boy is my fan LOUD.

But then, even though ear plugs and jet engine roar of the fan, came the pops of first crack! Chaff was flying, nice smokey smell, holy crap I'm roasting coffee! I wussed out, and I think I halted the roast a bit too early, (I would guess it's city, based on my meager knowledge and extensive googling, and I was going for city+ to full city).

Total roast time, 11 minutes. Hit FC around 9 min. Oh, and the chaff clogged up the screen and I was worried I wouldn't cool the beans fast enough, so I pulled the screen and blew chaff EVERYWHERE in the cooling phase.

I lasted a whole 4 hours before giving in and brewing up a quick pour-over. It was good! A bit, uh, flat? but it was coffee flavored, and I know that 4 hrs is not nearly enough outgassing time.

I'm hooked. Can't wait to do more!
-Keith
 
HoldTheOnions
On mine, the bean thermometer reads around 200, then I first drop the beans the air will slow down and thermometer will briefly spike to 240-250 and then it drops back down to right around 150 after a few seconds as the thermometer absorbs the bean temp and then generally works it's way back up to around 240-260 by the end of the first minute, depending on temps and batch size. So either everything is normal or we're both completely screwed. Grin
 
shortyjacobs
Wait, so we want to hit 240-260 within a minute? I thought it was supposed to take more like 4?
-Keith
 
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