I have had temperature probes in the factory set positions on my Quest M3.

Sometimes I need to decrease the temperature because the roasting is going to fast. I can then have problems understanding when I need to turn the power up agian, without the temperature starting to go down because of the delay in the temperature reading.

Easy example:
100C (power off) - 105 C - 105C -106C - 106C - 106C - 105C


I have tested out reading the temperature of the exhaust, coming out of the drum at two different positions. It did give a better temperature reading, but that might also have been because I used a "naked probe".

So:
I was wondering if others are reading the exhaust temperature, and in case, how?

Does anyone have experiences with opening the probe for the BT or ET? To increase the sensitivity to change in temp.

I would also appreciate other comments about reading temperature on the Quest.

The ET probe responds fastest if you change air and current at once. If you need to raise the temperature fast, lower the air flow and raise the current. Lowering the temperature takes longer: raise the ar flow and lower the current. When actually roasting, the bean temperature will not respond until maybe 30 to 40 seconds after you see a response on the drum temperature; in an empty roaster it goes faster.

The Quest is not as fast responding to control inputs as an air roaster or gas fired sample roaster; it's more like a regular shop roaster. You get used to making an adjustment and checking back in thirty seconds to a minute to see how its taken.

All 3 of my probes are naked, so they respond really fast. Probably the best option(for the bean probe)would be a really thin sheathed probe, bent as far down into the beans as you can get. But a naked probe is a close second, though it does take a while to position correctly.

hello,

it's great to find other quest users. sorry for the long post but I have been using the M3 for about 6 month and have two questions and could really use some advice.

okay, first question - which is the best location for the ET probe? I ordered two K-type probes from the factory. They are both pretty accurate and read the same exact temp when submersed in boiling water but when each of them are in the roaster I get two very different readings. the one placed under the trier can read as much as 10-12 degrees (f) lower than the once placed on the other side. I have been placing and using the probe located on the opposite side from the trier. I typically charge at 428 (f) - 220c with a 125 gram by weight batch. Before I knew this, with the probe located under the trier, I almost had a fire with each roast.

and, I have seen comments that say to turn the amps to zero when cooling as to not do a dry burn but when I pull the tray out and turn the amps back again to heat up the roaster I do not get any ET temp consistency from roast to roast. getting any kind of consistency has been very hard.

maybe these two issues are related to my problems getting consistent profiles? any suggestions?

Thanks... Dan

I mounted my ET probe where the stock analogue thermometer is mounted. EricS here used to sell them, but you'll have to email him directly to see if he still carries them.

Back to back roasting is actually easier once you get the hang of it. If you have your tray full of beans in the back getting cooled off, then the drum is still sealed off from most of the airflow ( all except natural gaps in the door, hole underneath, etc) and you can start your drying phase while you are cooling off your previous batch. When I end my first roast, I have my next batch of greens ready to load, so as soon as the basket is in the cooling tray, the next batch of beans gets dumped in with the amps set at or around 5.

Your previous beans will be cool before the drying phase is over on the new batch. At that point you have to remember to kill the fan until your drying phase is done. Otherwise as soon as you lift the basket out, normal air flow will return thru the drum.

Hi trosimon,

I am curious, I was thinking of doing the same as you did. What are your temperature differences between your two exhaust probes and the ET probe (Door open and closed) during the roast?

I am using http://users.rcn.com/erics/Quest_Thermocouples_03.pdf MET probe from Eric and the TC4C http://code.google.com/p/tc4-shield/. Both are great additions to simplify the process, to understand and study the roast afterwards.

Thanks Tom. I suspect that the temperature difference between the two locations is causing some of my issues. I have been seeing some tipping that I just could not get around. I'll move to the other mounting hole and see how that goes... should help with the back to back roasting.. I'll post my results after I see what happens... Dan

Here is a device a friend steered me toward yesterday. http://store.igrillinc.com/igrill-black/

I wonder if it would work on the Quest? 2 probes, appears to log data and give real time measurements and has high/low limit alarms AND works in the Apple environment.

At the price it is worth playing with if you are a MAC person

I wonder if it would work on the Quest?

Those probes are very likely equipped with thermistor sensing elements. I doubt that those particular sensing elements could handle the typical temperature ranges experienced with a coffee roaster. You would likely get an error message on the reading device.

All that said, a phonecall to the device seller would answer that question promptly.

erics wrote:Those probes are very likely equipped with thermistor sensing elements. I doubt that those particular sensing elements could handle the typical temperature ranges experienced with a coffee roaster. You would likely get an error message on the reading device.

All that said, a phonecall to the device seller would answer that question promptly.

Yes, I just sent an email to them for that very question. Using an i-Pad sure would be convenient!

I still want your probe set-up for the Amprobe

Thanks Eric!