Homeroasters - Home Roasting Coffee Community » ALL ABOUT ROASTERS » MY FIRST ROASTER
Who is here? 1 guest(s)
 Print Thread
How to get accurate temp readings
Petermet
Top  #1 Print Post
Posted on 01/02/2021 8:40 PM
I have just started getting back into roasting. I used to have a Behmor 1600 must have moved overseas and now use a simple stovetop setup.
My problem.is getting reliable temperature readings that are not simply from the hot air off the burner.

The first photo is the setup and the second shows where my current K thermocouple sits.
It does get "hit" by the beans every rotation but is widely affected by air thermals and any drafts.

Any advice on improving the setup would be welcome. Happy to do some work and spend some money to improve the setup. Ultimately I would like to use Artisan software.
Petermet attached the following images:
1609641131763.jpg 1609641131750.jpg
 
renatoa
Top  #2 Print Post
Posted on 01/03/2021 2:33 AM
Welcome ! BBQ grill

This was one of the phases of my evolution as roaster, I mean a perforated/mesh drum, and gave up, moving to other method.
Main reasons were hot basket handling, and temperatures measurement. Any temperature, not only beans.
Such setup is one of the few where your senses are the main factor you should rely.
Too many variables: gas pressure, environment temp, airflow around the drum.
Even if you manage to get a reliable temperature, what you can do to control? the stove knob is too coarse for the precision we need for a really "profile driven" roast.
My take would be to have a stable and reproducible heat, and find the sweet spot of the charge where the machine natural curve plays the best.

However, if I were a student and this would be an exam subject ... Grin I could have some ideas...
- one take would be to open the left side of the drum, to allow me place a probe that sink as much as possible in beans mass, with little as possible air or flame exposure. This can be done by changing the left side of the drum support method, from the shaft support as is now to an outer support , using two rolls mounted on the actual shaft support arms (the ^ wire)
- the second method much more radical, but moving your setup into another class, would be to modify your basket as the RotateFun300 roaster, check here to see what I mean:
https://hankua.wo...e-roaster/
If not clear, inside the drum there is an Archimede screw, that lift up the beans, to the opening where they drop back in the basket, and so on. The best design I ever seen for a home roasting perforated drum approach.

In the first phase there is no need to have an enclosure for the drum basket.
 
Petermet
Top  #3 Print Post
Posted on 01/05/2021 8:07 PM
Thank you 1 1/2 pounder.

I have relocated the K probe as you suggest and will give a try this afternoon. It sits nicely in the bean mass away from the heat source.

Thanks for your excellent advice ????
 
mtbizzle
Top  #4 Print Post
Posted on 01/06/2021 9:10 PM
This may have been mentioned
The quality of the K type probe can matter. I have heard that the phidgets k type (11cm, 3mm diameter) is considered good.
Roast: Kaldi wide, SR800 + projects
Grind: Lab sweet, Bentwood, giota w/ MP burrs, Commandante
Pull: Decent, La Pavoni, Elektra Microcasa a Leva, Faemina anno 60, Kim Express
 
renatoa
Top  #5 Print Post
Posted on 01/07/2021 2:29 AM
What means quality for a TC probe ?
The wires are made from two known alloys.
I would rather emphasize the importance of sheath than the TC itself.
The sheath is the interface that ensure the proper transfer from the measured environment to the junction.
People don't realise the importance of shape and other internal build details of this humble accessory.
 
Jump to Forum: