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Dull tasting coffee
harryf
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Posted on 04/23/2021 4:40 AM
I have been roasting with a modified Severin popper controlled with a TC4+ and Artisan for a few months and I still can't get what I would call decent coffee. I have used profiles I have seen others use with fluid bed roasters and played around with them but I'm just not happy. The roasted beans do not have that fresh roast smell, but more of a biscuit smell and the coffee produced tastes really flat and dull. Is there a recommended profile that suits these roasters best?
 
Koffee Kosmo
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Posted on 04/23/2021 11:24 PM
First question is
What coffee style are you roasting for

Not sure what profiles you are following but I find that most popper style roasters are way to fast by several minutes
Those minutes in the roast cycle are used for flavour development
Keep in mind you are not drinking the bean - you are drinking the oils and sugars extracted from the bean

Depending on the style of coffee you drinking

Before second crack = Filter, Pour over, siphon styles
At second crack = Espresso
Beyond second crack = Don?t go there Shock

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(KKTO) Turbo Oven Home Roaster.
 
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harryf
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Posted on 04/24/2021 10:37 AM
I am roasting for espresso based drinks, but I do not want a dark roast. I have never roasted to second crack, as far as I am aware. The noise from the popper fan makes it difficult, but if I go much past the end of first crack, the beans get too dark for me and the taste is burnt. I have attached graphs from Artisan to show some profiles I have tried. I wanted to attach 3 pics but only 2 worked.
harryf attached the following images:
save3.png save2.png
Edited by harryf on 04/24/2021 11:02 AM
 
renatoa
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Posted on 04/24/2021 12:37 PM
The hot air temperature is a bit too high, and could explain the burnt taste, because at 270C cellulose start burn.
The ET curve should cross the 200 C somewhere in the end of drying ballpark, then adjust the ramp, in order to reach 245 C about minute 6-8, and stay there to the end of the roast.

An example attached
...
renatoa attached the following image:
0225_antigua_et.png
Edited by renatoa on 04/24/2021 1:01 PM
 
harryf
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Posted on 04/25/2021 3:25 AM
Thanks for that Renatoa, but I need some help to follow your advice. I have set up the PID to get the BT to follow a background by controlling the ET. How can I lower the ET temperature and still get the correct BT curve?
 
renatoa
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Posted on 04/25/2021 8:13 AM
As the espresso standard diagnosing "if bitter, lower the temperature... etc", in the roasters case if too high air temperature, or too late FC, then you either have too much load, and PID is pushing too hard, either ET is not measured in the right location.

So this led to the next question set: how much load ? how is ET measured?

Can you plot also the heater %, i,e, the PID output?

The two images you posted are from two different profiles, right ? The timing is significantly different...
 
harryf
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Posted on 04/26/2021 4:06 AM
My popper has been modded exactly as in this article: https://www.instr...e-Roaster/, so the ET is measured just above the heater, as the air enters the roast chamber. If by load you mean amount of beans, then that is 100g. The beans move slowly at the start of the roast and gradually speed up, as per instructed.

I don't know how to plot the heater %, I need help with that.

Yes, the graphs are from two different roasts, as I was trying to improve things.
 
renatoa
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Posted on 04/26/2021 9:48 AM
In Artisan you should add the extradevice TC4 56, as in the attached image.
The heater and fan values will appear in the legend, and plotted in the graph as well.
...
renatoa attached the following image:
image_2021-04-26_174832.png
 
harryf
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Posted on 04/27/2021 3:36 AM
Thanks Renatoa, I have made that change and I will post again when I have done another roast.
 
harryf
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Posted on 05/02/2021 6:40 AM
Here is a roast I did showing the heater and fan values. I used 80g instead of 100g to see if that would improve things, but no. The FC points may not be accurate, as I was using a different bean and the cracks were very hard to hear over the fan noise, but I finished up with a medium roast, which is what I am after. I just wish it tasted better!
harryf attached the following image:
image1.png
 
renatoa
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Posted on 05/02/2021 8:07 AM
The curves allure is similar with one of my 50 grams roasts in a popper, that's why you see lower power levels to get the same result.
I am not plotting ET, no such probe, because calibrated everything at build time to not exceed 270 C in hot air. So my only guess is that your ET probe is somewhat off.

Sadly, the above still don't give you an answer to the bad taste you experience...
What about the beans ? Trusted source? Recent crop, not dried ? Do you have good roasts from them on another location/machine/method ?
renatoa attached the following image:
image_2021-05-02_161100.png
 
harryf
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Posted on 05/02/2021 9:17 AM
Thanks for posting the profile renatoa, as it's encouraging to know that what I'm doing looks about right. I don't yet have much experience of different suppliers, so there is a possibility of dubious quality. I will try another supplier next time I order. Watch this space!
 
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