Where does the thermocouple go?

[gronk62]

I bought a multimeter and thermocouple today.

Multimeter QM1320

Thermocouple QM1282

I aim my heat gun at the far side of the hopper. Where should I drill the hole for the thermocouple?

Ive had a trial run with the little wire probe that came with the DMM and am amazed at how much the temp changes just moving the position of the heat gun slightly.
I didnt have any beans in the hopper though.

[Dimal]

Re: Where does the thermocouple go?

I aim my heat gun at the far side of the hopper. Where should I drill the hole for the thermocouple?

Basically, from the same side as the heatgun Id reckon mate and at a height that will have the probe well and truly covered with beans from a typical batch size. If you think you might be going to roast varying batch sizes then it would be best to drill holes in a vertical plane so that the probe will be kept at a similar depth below the surface of the beans and just move the probe up or down to suit different batch sizes.

The name of the game with these is repeatability from one roast batch to another so that the data you gather will actually mean something as you roast more and more batches. If you havent already got one, its a good idea (almost essential really) to set up a Roast Log that includes a space for cupping notes. Theres quite a lot of info about this topic throughout the forum so if you do a search Im sure youll turn up some valuable stuff.

Coming together now, eh.... 8-)

Mal.

[gronk62]

Re: Where does the thermocouple go?

I aim my heat gun at the far side of the hopper. Where should I drill the hole for the thermocouple?

Basically, from the same side as the heatgun Id reckon mate and at a height that will have the probe well and truly covered with beans from a typical batch size.

Cool, thanks for that Mal. I didnt wanna go drillin holes before I established where. I hafta drill right through from the outside case of the BM, through the inner aluminium wall and into the bean hopper.
I guess that means my new BM warranty will be a bit useless  

Coming together now, eh.... 8-)

Mal.

Fingers crossed.

I got my new batches of beans today (Thanks Andy  ) and roasted 2 cups of PNG peaberry, and a second roast of 2 cups of Malabar.
I think the Malabar went well, but I had trouble hearing the cracks from the PNG and only really roasted by colour.
These were done prior to me buying the DMM and thermocouple.

I got my membership card today as well and todays roasts both sit around CS9 - CS10 and are much more even looking than the last 3, thanks to your great advice Mal  [smiley=thumbsup.gif]

[runfast]

Re: Where does the thermocouple go?

Gronk, I have the same DMM and one tip, it has an automatic turn off function to save the battery if not touched after x minutes (cant remember at the mo). I tend to turn it off and on (to reset it) at a point where everything is going smooth and i have a spare second.


Runfast

[gronk62]

Re: Where does the thermocouple go?

Gronk, I have the same DMM and one tip, it has an automatic turn off function to save the battery if not touched after x minutes (cant remember at the mo). I tend to turn it off and on (to reset it) at a point where everything is going smooth and i have a spare second.


Runfast

Yeah it turned off on me while I was running tests. I thought the battery had gone flat at first. :-?

[gronk62]

Re: Where does the thermocouple go?

Drilled holes in my BM today and have just finished my first roast using a thermocouple.

Im kickin myself for waiting so long to buy one

It just makes roasting so much easier to do.

but you already knew that..

[doryanthes]

Re: Where does the thermocouple go?

Gday all, got any suggestions about a way to protect the bead type thermocouples , I am on the way to building a roaster after going through 3KG beans in the popper , just taking too long ,and Koffee Kosmo seems to have a cunning plan almost ready to unleash .. got my turbo oven ready to go.. thanks Gaz

[Thundergod]

Re: Where does the thermocouple go?

Mine protudes into the pan through a small hole and is secure in place by a screw and washer.

[doryanthes]

Re: Where does the thermocouple go?

Thanks TG ,I read a post today by Andy that was more or less saying that the bead type thermocouples were a bit flimsy, so I wanted to check before destroying one, much appreciated . Gaz

[Dimal]

Re: Where does the thermocouple go?

Gday doryanthes,

For roasting, Id reckon the solid probe type t/couple to be more suitable, not only because it is more robust but the extra mass of the probe tip will average out the fluctuations measured by the bead type and probably be easier to read. Jaycar list one here... http://tinyurl.com/6x2rmq

Cheers,
Mal.

[Thundergod]

Re: Where does the thermocouple go?

Never one to question you Mal but my bead type probe is quite safe where it is and doesnt run the risk of being damaged, as a lot of solid probes seem to be.
Its robustness isnt called into question.

I dont have a picture, but the wires run back up from the outside of the pan to the meter.

I dont have to remember to pull the probe out before removing the pan.
I do have to remember to disconnect the wires at the meter, but if I forget, the meter comes with me to the cooling bucket.

I take your point though about the fluctuating readings.

My probe placement seems to be OK in that regard providing I am consistant with where the gun points.

[Dimal]

Re: Where does the thermocouple go?

I guess I was thinking more in a generic sense TG...

If the t/c bead isnt properly supported, it will eventually break one of the wires due to metal fatigue. In and of itself, this is no big deal either as you can create a new junction quite easily; just a bit annoying. From your description TG, I think my setup is very similar to your own... the probe is supported vertically and easily removed before emptying into the cooler.

Mal.

[Thundergod]

Re: Where does the thermocouple go?

I used to put my probe in vertically.
It was secured to the handle of a wooden spoon.
Now it barely pokes into the pan.
Heres the view from outside the pan.

[Dimal]

Re: Where does the thermocouple go?

Rightio TG...

With our Big Loaf BM, its just easier to come in from the top. It also avoids having to drill holes into a Dual Purpose BM.... Ours is still used to knead dough from time to time

Mal.

[Thundergod]

Re: Where does the thermocouple go?

My lead feeds in from the top between the pan and the body.
It doesnt make bread though so I can afford the hole.