Unexpected temperatures with Roastlogger

Roasters and roasting

Moderators: GreenBean, Gouezeri, bruceb, CakeBoy

Unexpected temperatures with Roastlogger

Postby Barrie » Sun Sep 22, 2013 2:42 am

I have posed a similar question on the HR forum, so hope that doing so here is not a transgression?
I have a Hottop with HTC/TC4 mod. Originally it was used for logging only, with a cheap probe through the chute. The results were perfect including 1C every time at around 400F. Then I put Omega XCIB-K-3-5-3 probes through the back wall. Since then both environment and bean temps look out of calibration, with 1C occurring around or just before 370F. The curves and relationship of one to the other look fine. Does anyone have any thoughts?
[img].[/img]
Last edited by Barrie on Sun Sep 22, 2013 12:48 pm, edited 1 time in total.
Barrie
 
Posts: 5
Joined: Sat Mar 30, 2013 9:51 pm
Location: Menlo Park, California

Postby GreenBean » Sun Sep 22, 2013 7:46 am

Different thermocouple installations, installed in different locations, will result in different readings. This is not to say that one thermocouple is reading correctly and another is incorrect it is a function of the installation not the thermocouple or the reading device.

With an installation of sheathed thermocouples through the bean chute the thermocouples are subject to radiated heat from the heating element and higher temperatures higher in the roast chamber. This results in readings higher than the actual bean or environment temperature at the tip of the sheath.

With any installation through the rear wall of the roast chamber some heat is conducted to the (relatively cool) rear wall resulting in lower temperatures at the thermocouple tip and, therefore, lower temperature readings.

Your readings are normal for the thermocouple installation you are using and are not a concern. The RoastLogger default action table settings are based on a first crack start temperature of about 374 F (190 C). So your new thermocouple installation is much closer to the default settings than your old installation.

The RoastLogger manual describes how to fine tune the action table settings to suit your particular case.
Image

Izzo Alex Duetto | Gaggia XD 2 Group | Mazzer Super Jolly | La Cimbali Max | Solis 166 | Dalian 1 kg roaster | Hottop P | Hottop B | French Press (several) | Kettle modded, no really, added digital thermometer |
User avatar
GreenBean
 
Posts: 2213
Joined: Wed Jan 03, 2007 2:15 pm
Location: Chester

Postby Barrie » Sun Sep 22, 2013 12:46 pm

GreenBean wrote:
With an installation of sheathed thermocouples through the bean chute the thermocouples are subject to radiated heat from the heating element and higher temperatures higher in the roast chamber. This results in readings higher than the actual bean or environment temperature at the tip of the sheath.

With any installation through the rear wall of the roast chamber some heat is conducted to the (relatively cool) rear wall resulting in lower temperatures at the thermocouple tip and, therefore, lower temperature readings.

Your readings are normal for the thermocouple installation you are using and are not a concern. The RoastLogger default action table settings are based on a first crack start temperature of about 374 F (190 C). So your new thermocouple installation is much closer to the default settings than your old installation.



Thank you so much, gb. That is clear, to the point, and immediately understandable. It means I don't have to talk myself into believing that I have accurate measurements. I do! :D The default first crack number is very interesting.
Barrie.
Barrie
 
Posts: 5
Joined: Sat Mar 30, 2013 9:51 pm
Location: Menlo Park, California

RoastLogger code

Postby Barrie » Sun Sep 22, 2013 5:27 pm

Now that my probes have been "approved", is it possible to edit the RL code? I am interested in custom-labeling graphs.
Barrie.
Hottop B-2K with HTC/TC4C mod.; Jura Capresso Ena3.
Barrie
 
Posts: 5
Joined: Sat Mar 30, 2013 9:51 pm
Location: Menlo Park, California

Postby GreenBean » Sun Sep 22, 2013 6:28 pm

All the information to recreate the chart is contained in the roast logs. The chart is recreated whenever you load an existing roast log. Due to this it is not necessary, in normal use, to save the chart.

You can store any information you wish in the roast log and you can choose any file name for it i.e. one that includes all the information you need to identify the roast.

Due to the above I have not seen much need to provide custom editing of chart labels. I will, however, consider providing these facilities in a future revision of the RoastLogger. For now I would suggest you use any image editor if you want to add or change labels in a saved chart.
Image

Izzo Alex Duetto | Gaggia XD 2 Group | Mazzer Super Jolly | La Cimbali Max | Solis 166 | Dalian 1 kg roaster | Hottop P | Hottop B | French Press (several) | Kettle modded, no really, added digital thermometer |
User avatar
GreenBean
 
Posts: 2213
Joined: Wed Jan 03, 2007 2:15 pm
Location: Chester

Postby Barrie » Sun Sep 22, 2013 7:40 pm

Thanks for the response. I understand. It was just that as an erstwhile programmer the thought was irresistible. :)
Barrie.
Hottop B-2K with HTC/TC4C mod.; Jura Capresso Ena3.
Barrie
 
Posts: 5
Joined: Sat Mar 30, 2013 9:51 pm
Location: Menlo Park, California

Postby Barrie » Sun Sep 22, 2013 10:03 pm

GreenBean wrote:All the information to recreate the chart is contained in the roast logs. The chart is recreated whenever you load an existing roast log. Due to this it is not necessary, in normal use, to save the chart.


I have only completed about 350 roasts, 110 in the HT, and am still very much a learner. One day I hope to reach the plateau of "normal use" but am not there yet. For example, as I examine RL records for different bean roasts with a view to improving on them, I would like to be able to compare print-outs of their charts. "Roast Logger Profile" is too generic for my purpose, whereas bean and date information would be more helpful. Granted, each user will see this from his/her own perspective.

Lest I seem unappreciative of this excellent software that cost me nothing, this is anything but the case. It is great!
Barrie.
Hottop B-2K with HTC/TC4C mod.; Jura Capresso Ena3.
Barrie
 
Posts: 5
Joined: Sat Mar 30, 2013 9:51 pm
Location: Menlo Park, California

Postby GreenBean » Mon Sep 23, 2013 8:38 am

Comparing print-outs of previous charts would be a very inefficient, ineffective and completely unnecessary way to proceed. Print-outs of previous charts would only show a direct comparison of that particular roast against the template used for that roast.

The RoastLogger can be used to directly compare ANY two previous roasts simply by loading one as a template and one as the current roast. When doing this the roast profile curves and the roast stage markers and tables are recreated allowing direct comparison of any two roasts.

I suggest you save roast logs for different beans to different subfolders or include the bean name in the filename.
Image

Izzo Alex Duetto | Gaggia XD 2 Group | Mazzer Super Jolly | La Cimbali Max | Solis 166 | Dalian 1 kg roaster | Hottop P | Hottop B | French Press (several) | Kettle modded, no really, added digital thermometer |
User avatar
GreenBean
 
Posts: 2213
Joined: Wed Jan 03, 2007 2:15 pm
Location: Chester

Postby bruceb » Mon Sep 23, 2013 9:31 am

That is really one of the many advantages of the RoastLogger. I use it that way on every roast, comparing different beans and comparing the present roast to past roasts with the same bean.
BTW, I have folders for different countries or regions, ie. South America / Brazil, etc.

GreenBean wrote:Comparing print-outs of previous charts would be a very inefficient, ineffective and completely unnecessary way to proceed. Print-outs of previous charts would only show a direct comparison of that particular roast against the template used for that roast.

The RoastLogger can be used to directly compare ANY two previous roasts simply by loading one as a template and one as the current roast. When doing this the roast profile curves and the roast stage markers and tables are recreated allowing direct comparison of any two roasts.

I suggest you save roast logs for different beans to different subfolders or include the bean name in the filename.
Three Francesconi (CMA) espresso machines - Rossi, San Marco, LaCimbali, Faema and 2 Mazzer Major grinders- CoffeeTech Maggionlino, Hottop, Alpenröst and HW Precision roasters.
I decided I needed a bit of a change so I roasted some Monsooned Malabar. That was a change!
Image
User avatar
bruceb
 
Posts: 5361
Joined: Sun Apr 04, 2004 12:49 pm
Location: Northern Hesse, Germany


Return to Roasting - Equipment and Techniques

Who is online

Users browsing this forum: No registered users and 2 guests

cron