Hi,

A bit of background, I have a home designed and built fluid bed roaster with an approx 3600w element and an IR thermometer.
The roaster uses my own programming language and is very responsive.

As an example:


The blue line is the actual bean temp, the red is the et from the heater unit, orange is the power output from 0 - 200.

The profile programmed is:
STA,0 #Start, wait for nothing, must be first
MET,370 #Maximum Environment temp is 370c
MHP,180 #Maximum Heat Power is 180, Tone it down for small batches
SHP,45 #Warm up the beans gently
WBT,35 #Until 35c and then let it go..
PBT,77 #PID Bean Temp to 77c
WBT,70 #Getting close, slow down earlier.
MHP,80 #slow down for the corner
WBT,77 #Start of controlled rise
RBR,25
MHP,200 #Remove restrictions
WBT,127
RBR,14 #Slowed down to 4.5 minutes. Was 3.5
WBT,190
RBR,25 #Hard push into first crack
WBT,213 #First crack
RBR,4 #Slow ramp to the end, was 6 but stretched. Now 2.4m instead of 2m
WBT,226 #End at 2nd crack
SHP,0
SAP,55
WBC,35
SAP,20
END,3

The key commands are WBT= Wait for Bean Temp, RBR = Rate of Bean Temp rise per min, PBT = PID Bean temp by adjusting ET, WBC = wait for temp below.

I roast for an espresso machine, beans like Mexico El Malinal, Monte Alegre Estate Natural, Daterra Estate Sunrise etc.

The IR thermometer measures the actual bean temperature, 1st crack seems to be around 214c depending on the variety, within 3c.

As you can see, it is very flexible.

So what is the correct answer?

best regards

Lee

Wow, it does seem responsive! Any chance you will post some photos of it? Unless your just roasting one bean, having a set profile that never changes is going to be hard. Is it difficult or time consuming to change the profiles with your software?

Hi Lee, nice to see you here. I remember your awesome fluid bed from homeroaster.org Any recent videos?

Not sure there is a correct answer, but what I would try to change is speed things up a bit, cutting the dry time to 3.5-4 minutes, 1st crack around 7-8 minutes. Instead of going hard to 1st, try going very slow, and compare. Finish around 10-11 minutes. Add pre-heating to 100c-150c. My fluid bed gave me better results by going faster, made things more pronounced.

It appears you have a reactive roaster and the monitoring abilities needed. Your BT-RoR will clue you in as to how the beans are reacting to whatever heat input your providing. This allows you to try several controlled approaches and cup the different results to taste. Beyond the differences of working with softer and harder beans there is also the ability to somewhat manipulate characteristics, acidity, body, flavor development etc. Different designs of roasters will accomplish these manipulations basically the same way but also somewhat specific due to the design. This is where becoming one with your roaster and being able to distinguish and adjust from the cup becomes essential.

@dustin,
Profiles are easy to change, you simply write it into a text file using notepad as per the example above. anything after a # is a comment, not needed for the program.
The SD card that holds the programs is removed and plugged into a pc for editing.

I will give the profile a tweak and check the results.

I will take some photos today and post.

regards

Lee

Great, I would love to see a video/photos of your roaster in action. Do you not like playing around with profile on different beans? 99% of the reason I roast is the fun I get trying different things(times/temps/fan).


(oh, and what is the very bottom line in your profile represent?)

Overview showing the complete roaster, starting from the top, IR Thermometer, Air handler (grey box) chimney, roast chamber (glass) heating chamber, blower (white box)

Ok, I'm jealous.

Lee, what's your ejection method? How does your perforation look? The narrow heat chamber is impressive (among many other impressive things) how it can hold your mica + element!

Struggling to upload more than one pic per post so this may take a while..

This is the element, as you can see it is just flat sheets of mica and a brass bolt and insulators.

The wire for the connections is coat hanger wire. The cross section of the mica looking from the top is a snug fit in the pipe so it holds it in the centre.
I just run a bolt right across the pipe at the base through the hole in the centre of the bottom insulator.

The earth is of course connected to the metal pipe.