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01/12/2021 6:15 PM
@Nomad As a general rule Roasting should not exceed 20 min to second crack You are describing is baking

12/31/2020 2:39 PM
I trying another 2 cups at 200 for 45 min

12/31/2020 2:38 PM
I have a questions.. im trying to experiment with riasting.. i roasted 3 cup of nicaraguan at 200 degrees for 1 hr and 30 min.. is that to long?

12/17/2020 11:16 AM
Snow again in NC.

12/13/2020 3:51 PM
I didn't realize snow was forecasted for this neck of the woods

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Aliexpress Fluid Bed roaster 300g
trisse
Hi! This will be my first post here. I want to make a reviw on my newly bought fluid bed roaster from aliexpress

First of all im very happy with my purchase. I payed a total of 600 dollars for this machine including the usb dongle for connection to computer. The roaster have a lot of power both on the fan and the heater i normal use about 70% of the heater capacity and only max 50% of the fan.

Something that not work so well is the chaff collector. When connection a ventilation hose, the chaff collector have a tendency to leak and spout chaff all over the place.

The included thermocouples are k type and seems not to be so accurate. Also i think the BT probe is to short so i have ordered a new longer probe.

Feel free to ask me anything and please give me some tips on how to roast better.
trisse attached the following images:
honduras_snabb.png honduras_cerro_azul.png
trisse
Here is more pictures

i.ibb.co/1fK01gH/20201103-135428.jpg
i.ibb.co/Yhtrs9S/20201103-135432.jpg
i.ibb.co/0J0LZMj/20201103-135438.jpg
i.ibb.co/tBFTy8g/20201103-135448.jpg
i.ibb.co/FgBGP44/20201103-135453.jpg
i.ibb.co/4KjRcHw/20201103-135458.jpg
renatoa
Congrats for your purchase, for the limited FB offer of this capacity range on the market, seems a well balanced price.

Beware, a longer BT probe will come in the hot air path, and could be fooled by the different air/beans mix in the center.
As is now looks ok, why do you think it is not accurate ?
trisse
Thank! It feel like a good purchase. I get very even roasts and they are starting to taste good. On the first few batches i did start with to low temperature so the coffee didn't turn out so well.


Well I donĀ“t think its accurate because i get first crack at 130-150 degrees C. Also when i do back to back roast i get very different curves. I think the BT probe is measuring the metal in the bottom of the bean tube instead of the bean. The roaster have 2 probes sitting over the heater. One of those goes to the display on the roaster and the other one goes to artisan as the ET temp. It feels kinds off if it never goes over 200 degrees C. if i turn up the heater more i get 3 min roasts

Here is some of the roasts i have done
trisse attached the following images:
honduras_snabb_1.png honduras_monte_cristo_frsta.png honduras_misstag.png etiopien.png brasilien_-_copy.png
renatoa
Well the numbers on graph don't read so well, that's why I asked.
So what I imagined to be the 200 C line is actually 150 C, which indeed is not a realistic FC landmark.

For the future please use Artisan File menu, Save Graph command, and choose at least the 700 pix (Home barista) format, is the smallest with very good readability, imo.
trisse
Oh sorry I didn't notice that.

I have ordered 3 probes for Aliexpress, 3mm diameter, 50mm long with m6 screw should fit my unit. But I don't think I can change the probes over the heater.

Maybe i should just change the bt probe and but one in top chaff collecotr for et?

I'm i right going high with the heater in the start and then lowering? I don't see another way theget a declining RoR.

Also my temps (both bt and et)get lower when I lower the fan.
renatoa
You should not try to mimic the heat dynamics of a drum roaster, FB and drum are completely opposite as strategy.
While the drum store energy and deliver to beans gradually, in a FB the beans temperature increase is mainly driven by air temperature increase, contact or radiant heat are minimal.
In order to drive a FB roast with unreliable BT temperature measurement, you should rely more on air temperature and relate desired BT to power levels.
The air curve should be somewhat parallel and about 50 C above the desired profile, but not more than 250-270 C.
I would preheat at 100 C, to have a margin when loading the beans, then start to increase power almost proportionally with the profile, this is how I achieved my best results with a FB machine. The start power level should be found by experiments, a value to bring the air to ambient + 50 C degrees. This was 24% for 75 C in my case.
From there I start increase power one percent every 3 degrees, arriving to 200 C with power about 70%.

Check attached graph for an example of such roast. ET is not logged, the red graph is power. If rescaled, it is almost parallel with BT graph. Every % of power in a FB has direct and proportional impact in beans temperature, some seconds later.
renatoa attached the following image:
0912_cr_nat_-optimal.png
trisse
Wow thank you for a detailed post. I will definitely try this.


It pretty much opposite to what I have done earlier.

As you see on the picture i have knobs without values controlling the heat. I think it Will be pretty hard increasing with exactly 1 % but maybe is not that accurate?

Good idea to preheat. I think it will be easier to do back to back roasts and comparing profiles if i do that
renatoa
I thought the usb adapter provide also backward link, to control power from Artisan... yeah, with a knob will be harder...

btw, how you see this roaster from Artisan, what device compatibility ?

Just noticed this post from drake39:
https://homeroasters.org/forum/viewth...post_72625
... the image illustrate pretty well the "ET parallel and above BT by xx degrees" concept I wrote in my post.
In his case the difference is about 30 C degrees, of course this value depends on machine build and dynamics.
Edited by renatoa on 11/03/2020 1:49 PM
trisse
The little round thing on my pictures are a bluetooth dongle for the probes. In arisan i choose tc4 as and change port if i remember correctly. I can post a picture of the manual but it is in chinese. You gotta love google lens.

I had to change baud rate(?) To 9600.

Remember on my pofiles the ET are actually a probe just above the heater.
renatoa
For me E is for Environment always, not exhaust.
Is the hot air surrounding beans that drive the roast, not the air leaving chamber.

OK, so it emulates TC4 protocol, good to know... and not surprising, it's almost a standard.
I see here the first step for improvement, replacing electronics with a full TC4 solution, allowing you a better heater control.
trisse
Yeah I know, but i didn't figure out how to change name in artisan. The machine came with 2 thermocouple one above the heater and one as BT.t The usb dongle have connection for two probes so i fitted them both for as much information as possible.

I have been thinking fitting the machine with a complete tc4 control. But it looks hard to open. With a guide/howto I could probably to it.
trisse
Got a new 3mm thermocouple for BT today. Much better readings, would have bought 2 but they only had one in stock

Here are some roasts i did today
trisse attached the following images:
colombia_batch2.png colombia_batch1.png
trisse

Quote

renatoa wrote:

You should not try to mimic the heat dynamics of a drum roaster, FB and drum are completely opposite as strategy.
While the drum store energy and deliver to beans gradually, in a FB the beans temperature increase is mainly driven by air temperature increase, contact or radiant heat are minimal.
In order to drive a FB roast with unreliable BT temperature measurement, you should rely more on air temperature and relate desired BT to power levels.
The air curve should be somewhat parallel and about 50 C above the desired profile, but not more than 250-270 C.
I would preheat at 100 C, to have a margin when loading the beans, then start to increase power almost proportionally with the profile, this is how I achieved my best results with a FB machine. The start power level should be found by experiments, a value to bring the air to ambient + 50 C degrees. This was 24% for 75 C in my case.
From there I start increase power one percent every 3 degrees, arriving to 200 C with power about 70%.

Check attached graph for an example of such roast. ET is not logged, the red graph is power. If rescaled, it is almost parallel with BT graph. Every % of power in a FB has direct and proportional impact in beans temperature, some seconds later.


Tried to mimic roasting this way manualy. It is tough, my knob is very sensitive. Here are the two roast trying this way. I think its very hard controlling RoR. i can get it to decline over the hole roast, but i get several flicks and bumps. Any idea?
trisse attached the following images:
batch_7.png batch_8.png
renatoa
When ET is lower BT, and ET is the output of hotgun, clearly there are issues in temperature measurement, so can't judge anything.

Do you have any feedback of knob rotation on display ? Is the knob stepless ?

You could adapt another knob, like below, for more precise adjustment:
https://www.tme.eu/en/katalog/precisi...rs_112335/

Or, simpler, replace the power control with a digital unit, very cheap, more precise and reproducible than a pot:
https://www.ebay.co.uk/itm/AC-220V-40...4377031174
trisse
I changed the bt probe to a 3mm and got better readings. Now I get first crack when I suppose to. The ET probe is still the original. I would have changed both but the store only had one in stock.

I have a display showing the heater settings through voltage. It's step less but kinda hard to make fine adjustment. If i would to upgrade it it would be with a tc4 so i can controll it by artisan. I have been reading about about it. But i feel i wanna do some roast first
renatoa
Maybe a demultiplier knob is the immediate solution for finer adjustment, if you have voltage display.
But beware, power is square of voltage... so % of power equates to a different voltage curve than you see in roasting graphs.
trisse

Quote

renatoa wrote:

Maybe a demultiplier knob is the immediate solution for finer adjustment, if you have voltage display.
But beware, power is square of voltage... so % of power equates to a different voltage curve than you see in roasting graphs.


I see ! Didn't know power was square of voltage. That explains why the big difference in temp when using 170v and 180v.

Hmm how should I approach your recommendation with increasing power by one % every 3 degree ? I last time I tried to go 3v higher but i see now that not correct
renatoa
When using AC sine wave chopping you are controlling the effective power passing to heater, not voltage.
For example, in EU mains is 50Hz, i.e. 100 half sine cycles. The control element act a high speed switch that let pass or stop these half sines to the heater. For example 75% means letting 75 pulses and stop 25, every second.
For US you have 120 pulses per second, so the on/off counters are 90/30, but the ratio is the same: 75%.
The voltage remains the same, is the power itself that is (precisely) modulated.
That's why I can dose the power as the profile requests it.

Now that you told me, and I wrote the above, I am wondering what control circuit you could have inside your box, able to deliver a variable voltage in a so small footprint... this is usually done with (big) transformers.
A solid state controller would operate as I described above, so the voltage on display should be always mains voltage - 110/220V - not variable with the knob... unless the display is a true RMS meter, which are quite expensive... maybe not for chinese Grin

Regarding voltage variation and power %, is difficult to do this without permanently computing... 1V change at 100V means 2% as power percentage. But the same one volt variation at 150V means 1.3%, so... you need a table Grin
trisse
Damn! Very interesting post. Got me curious about what's inside my machine. I have this picture of what is the backside of my voltage display if that saying you something. I will try to take some pictures of the inside of the machine tomorrow but i think i will get any good photos.

Thank you for taking the time to respond
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