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JackH
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· 07/04/2020 10:27 AM
Happy 4th of July! jazzyhands

JackH
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· 06/24/2020 7:58 AM
@Mark McCornack, Please post your question in the forum.

Mark McCornack
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· 06/15/2020 9:28 PM
Hi! Looking for a legacy inlet temp sensor on 13 yr old Gene Cafe. It seems they've changed it and now you need new mother board and new sensor. Any ideas where I can find compatibile old one? Mark

Samaniego
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· 06/09/2020 6:39 PM
Wich thermometers Can i buy for my roasting machine compatible with usb or macbook?

JackH
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· 06/05/2020 5:38 PM
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Building a drum roaster
allenb
When you get around to the next roast send all you got. Trust me you're not going to bore anyone with the long version. This helps everyone, especially folks who are at the testing phase of their new build.

When you add an outside the drum ET probe I think you'll find a nice improvement in your ability to steer the roast and anticipate temperature changes.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
Ringo
Allenb- looks like you were right, I did a couple of roast tonight with the FT "fire side" probe installed it seems to be a good piece of information. I am going to post the logs, I was attempting to slow the roast at 300 BT for drying and 350 BT for carimalization. 1c came faster than I wanted so I will have to work on this next roast.
Sumatra Permata Gayo
Drop 255 BT
:30 BT 188 ET 206 FT 285
1:00 BT 161 ET 181 FT 306
1:30 BT 168 ET 188 FT 322
2:00 BT 181 ET 204 FT 326
2:30 BT 201 ET 223 FT 332
3:00 BT 220 ET 241 FT 344
3:30 BT 237 ET 258 FT 353
4:00 BT 254 ET 275 FT 362
4:30 BT 267 ET 289 FT 368
5:00 BT 280 ET 301 FT 375
5:30 BT 292 ET 313 FT 380
6:00 BT 303 ET 323 FT 376 Gas moved to 70 %
6:30 BT 311 ET 331 FT 368
7:00 BT 318 ET 339 FT 362
7:30 BT 324 ET 345 FT 360
8:00 BT 329 ET 350 FT 357 Gas moved to 100 %
8:30 BT 336 ET 356 FT 364
9:00 BT 343 ET 364 FT 375
9:30 BT 351 ET 371 FT 385 Gas to 70 % for carrimalization should do sooner.
10:00 BT 361 ET 381 FT 385 1c starts gas to 50 %
10:30 BT 363 ET 384 FT 373
11:00 BT 364 ET 384 FT 353
11:30 BT 364 ET 384 FT 348 gas to 60%
12:00 BT 365 ET 385 FT 351
12:30 BT 369 ET 389 FT 358 1c stops
13:00 BT 374 ET 394 FT 360 I pulled the roast, nice city ++

So I am open for ideas, I have not taisted this coffee yet it needs to rest but I think I will miss a little sweetness. I blew past 350 deg to 1c much faster than I wanted. With this big steel drum I will have to anticipate changes a little soomer.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
allenb
Is your "FT" sensor close to the location where combustion air enters the drum?

The reason I ask is I'm not used to seeing combustion air temp that low but there might be some outside air/combustion air mixing at the point where your sensing.

In any case it's very useful info. You can see where you dropped down to 70% at min. 6 causing a drop from 23 degrees/min down to 15 and 11/min. After that you kicked it back up to 100% at min 8.

I'm thinking with the thick drum you've got you will probably want to avoid trying to make many abrupt swings and concentrate more on making a couple of smaller ramp changes for drying phase to roasting phase and roasting to 1C and beyond. You might also try a little hotter drop in temp.

It will take a little getting used to with the delayed temp reactions but you'll pick it up soon enough.

Keep the updates coming in.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
Ringo
The FT is the combustion gasses right before they enter the drum, I pull a lot of air through the drum while I am roasting so this air would be well mixed with excess air, this has me wanting to try less excess air with a lower burner thinking the drum may be a little cooler while roasting. Lots of things to try, I will be tinkering for a long time.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
allenb
Until you've logged some miles with your new roaster I would pick an airflow just high enough to move the smoke and chaff out and leave it locked in to keep variables to a minimum. You'll then only be varying burner output to steer the roast. You'll most likely see a higher outside the drum ET with the reduced airflow which is fine.

Once you've gotten comfortable with it you can start experimenting with airflow changes to allow "tighter turns" in your ramps.

I can't remember how you said you are monitoring gas input or burner output but a lot of folks have found improved control by adding either a magnahelic or utube gas pressure meter to allow tight burner control. I'm an old boiler guy and I understand you are too so I'm sure you've already kicked that around.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
Ringo
I should tell people how I ended up controling the gas if anybody is thinking abought building a pipe burner. Changes in presure of the gas do not change the output of the burner much so I had to install a needle valve in the 1/8 inch feed line. Small turns in the valve make big changes in the burner. I look in the window and judge heat imput by flame size, I can turn one burner off compleatly for much lower heat imput but I have not needed that yet. I think when I start learning to run small roast I will need to run at times with one burner off. I do not think a magnahilic will help on this roaster, I use them at work and they read presure differentials, my roaster firebox and roaster is so open to airflow air is not restricted so very little differental presure. This was by design, I wanted too much air flow so I could dial it back for controll, heat flows around outside of drum freely at the top of drum heat is pulled out of the fire side and through the drum. Another possible project someday is to add some baffles under the burners to control how much excess air gets in. Comercial drum roasters seem to have these. I forget the word but I will rig up a piece of flexable tube and put water in it to see what kind of vacuum I am pulling soon, "utube" thats not it.
Edited by Ringo on 06/16/2010 7:40 AM
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
Brainiac

Quote

Ringo wrote:
I forget the word but I will rig up a piece of flexable tube and put water in it to see what kind of vacuum I am pulling soon, "utube" thats not it.


Manometer

http://www.upscale.utoronto.ca/PVB/Ha...meter.html

Brian
 
allenb

Quote

Ringo wrote:
I do not think a magnahilic will help on this roaster, I use them at work and they read presure differentials, my roaster firebox and roaster is so open to airflow air is not restricted so very little differental presure. This was by design, I wanted too much air flow so I could dial it back for controll, heat flows around outside of drum freely at the top of drum heat is pulled out of the fire side and through the drum. Another possible project someday is to add some baffles under the burners to control how much excess air gets in. Comercial drum roasters seem to have these. I forget the word but I will rig up a piece of flexable tube and put water in it to see what kind of vacuum I am pulling soon, "utube" thats not it.


I've gotten used to calling a water column style manometer a utube.

If you put together a simple clear flexible tube inclined manometer with hopefully no steeper than a 30 degree angle, you should be able to see small changes in very low gas pressures pretty easily. Most folks put a red or blue food coloring in the water and place a white paper behind it for visibility. You can also mark some graduations on the paper or use a finely ruled graph paper.

I wasn't implying that you should measure combustion gasses flowing up from the burner but was thinking you would have enough gas pressure between your metering device and burner to get a reading.

There's different magnahelics out there, some are for measuring differential pressures and others (the one I'm referring to) are single input pressure gauges going down to hundredths of an inch H20. Unfortunately, these guys aint cheap. You can also get a digital one by Dwyer for around $80 (Graingers price) that has a resolution of .010".

Without knowing how low of a pressure you've got after the needle valve it's hard to know if the digital unit would read low enough.

One good thing about the inclined tube is you can keep lowering the angle till you get the resolution you need then pin it in place.

I'm not sure how one should use one of these (u-tube) arrangements to not have a safety issue measuring a combustible gas. Maybe some of our fellow home roasters using gas fired roasters could weigh-in with how to make the setup safe?
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
Ringo
I did not realize you were talking gas presure after the needle valve that would be really good to have. Now you got my mind rolling, thats not a good thing sometimes. That would be positive presure much easyer to read. I believe that a part of the puzzle, it should give me a way to estimate heat imput. Thanks for the idea!!
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
allenb
Take a look at page 4 of this PDF on making your own test setup (hvac related): http://www.dtec.net.au/Tech%20Article...Design.pdf

He's got a pretty slick inclined tube setup with a fluid reservoir.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
dja
I read the article that Allenb pointed to, good paper but its actually a flow bench setup for carburators and such.

you can get a Dwyer Slacktube or U-tube Manometer in a 24" size from WW Grainger for about 25.00 bucks last one I purchased. Or just get some heavy wall clear vinly tubing 1/4" ID and a measure tape, water and Iodine for fluid, for more critical measurments get gauge oil from grainger 4 oz bottle probably about 10 bucks.

don't ya just love the scientific stuff that a homely little coffee roaster will bring out in ya!ThumbsUp

Hows the roaster doing?
I pour Iron and roast Coffee BeansThumbsUp
If life seems normal your not going fast enough Mario Andrette
 
Ringo
Allenb
I took your advice and tried a roast with low air flow low gas, it was a compleat different roast. The roast was much slower, but I feel like it smelled much better. One more time, thanks for the advice. I did a high airflow roast at the same time and will cup them in a couple of days. One thing that was interesting is with low air flow the probe in the firebox is hotter than the ET probe, less radient heat on the drum. If this style roast cup well I feel like I could easy roast 4 pounds at a time.
1 min BT 193 ET 255 FT 286
3 min BT 231 ET 270 FT 276
6 min BT 272 ET 308 FT 310
9 min BT 307 ET 349 FT 359
12 min BT 363 ET 410 FT 433 1c was 359
13.30 BT 375 ET 392 FT 375 1c ended
15.00 BT 392 ET 406 FT 394 Pulled roast City plus
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
allenb

Quote

Ringo wrote:
Allenb
I took your advice and tried a roast with low air flow low gas, it was a compleat different roast. The roast was much slower, but I feel like it smelled much better. One more time, thanks for the advice. I did a high airflow roast at the same time and will cup them in a couple of days. One thing that was interesting is with low air flow the probe in the firebox is hotter than the ET probe, less radient heat on the drum. If this style roast cup well I feel like I could easy roast 4 pounds at a time.
1 min BT 193 ET 255 FT 286
3 min BT 231 ET 270 FT 276
6 min BT 272 ET 308 FT 310
9 min BT 307 ET 349 FT 359
12 min BT 363 ET 410 FT 433 1c was 359
13.30 BT 375 ET 392 FT 375 1c ended
15.00 BT 392 ET 406 FT 394 Pulled roast City plus


It will be interesting to hear how much of a difference you find with the two roasts. Your bean temp read out at 1C is quite a bit lower than what I'm used to seeing which is typically between 400 and 405F. I know this can vary a bit from roaster to roaster.

If we add 37 degrees to your 272 at minute 6 I believe your hitting the 300 mark between 5 and 6 minutes which is within the typical time range.

If this roast doesn't cup out the way you like I would try and get the rise per min up in the 20's during the 2nd phase of the roast (for a while you're in the 11-13/min range between minute 3 and 9).

My advice again would be to find a sufficient air flow for chaff removal and play with burner output to keep the variables down to a minimum during future experimentation. I would also dig further into how your probes are sensing. Maybe get another read with a couple of bare TC's into a handheld meter to verify your current readings.

Keep the feedback coming!
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
Ringo
I have been roasting 1 pound batches lately, the probe is in the beans just not as deep. I believe 1 pound batches will read 15 deg cooler than actual temp. The one pound batches let me test more profile theories. As I test out each roasting theory I want to do two roast of the same coffee, one contoll and one with a change. Then cup side by side. I did drink the slow roast coffee this morning on 12 hour rest it was very good, I think this is going to be better. Aroma miles ahead. I noticed during the roast much less smoke with the slow roast low air method. Maybe the next "theory" will be lower air still.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
Ringo
I tried both roast, the high heat, high air flow fast roast next too low air low heat slow roast. There is no comparison, the fast roast is flat with nothing special. The slow roast is great. As I am starting to learn how this drum works I now see, if I pull lots of air through the drum the gas is wide open, flames are hitting the drum. I ran high air to try to get more convection like an air roaster but the I now think I heated the drum steel so hot I got more radiant heat. After around 20 roast I now think this thick steel drum is going to be great for me, I can move the roast slower or faster. The problem with the mass of steel is after a roast everything is heated to 400 deg, it takes 10 min to get it cooled of to drop temp. At home thats fine, in a commercial setting that delay would kill you. I can do two loads an hour, with less mass I could do three. If I was building a new roaster today I would keep the thick steel.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
Ringo
I wanted to do an update on my roaster just incase somebdy is going to build one. I have used the roaster for a lot and its doing a good job. I made a change to how I cntrol the heat. I used the needle valve and just looked at the height of the flame to judge BTU input, now I used the adjustable pressure regulater to adjust heat imput, this is much better. I have a number to match on different roast. I run gas pressure at 12 pounds at the start, this gives me a ROR of 16 to 18 degs every 30 secs. At 300 deg I cut pressure to 11 pounds this gives me a ROR f 11 deg every 30 secs. At first crack i turn one burner off and set presure to 4 or 5 pounds looking for a ROR of 4 every 30 sec. If anybody is building a pipe burner this is a better way to control heat.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
allenb

Quote

Ringo wrote:
I wanted to do an update on my roaster just incase somebdy is going to build one. I have used the roaster for a lot and its doing a good job. I made a change to how I cntrol the heat. I used the needle valve and just looked at the height of the flame to judge BTU input, now I used the adjustable pressure regulater to adjust heat imput, this is much better. I have a number to match on different roast. I run gas pressure at 12 pounds at the start, this gives me a ROR of 16 to 18 degs every 30 secs. At 300 deg I cut pressure to 11 pounds this gives me a ROR f 11 deg every 30 secs. At first crack i turn one burner off and set presure to 4 or 5 pounds looking for a ROR of 4 every 30 sec. If anybody is building a pipe burner this is a better way to control heat.


Very cool. You really seem to have gotten this beast under control using the pressure reg.

Are you using the rate of rise meter or just watching the readout and timing it?

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
Ringo
I have the parts ordered for the ROR but they are not all here yet, so I do the math as I hand log. I will be very happy when there is no more hand logging my roast will get better with more time to watch everthing. Believe me I have lots to learn with roasting with the drum but its getting better. I did a .34 lb roast today, turned one burner off for the roast I think it will be good. So I have roasted .34 to 2.5 pounds. 1st crack was 20 deg hotter with the little bean load, not sure why.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
Ringo
I wanted to find out how large a roast I can do last night. I dropped 6 pounds in and it roasted great. I was able to get 6 pounds to 300 deg in 5 min, finished the roast with a city+ in 11:20 min.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
Vidget
HELLO, whether to create some drawings for the construction of your roster? and can you share them? I'm starting to develop and further construction of his home drum roaster and would like to take yours operating time to speed up the process if you do not mind.
 
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