Charge Temp and Environmental Temp ?

Law104

New member
Jun 20, 2019
27
0
Empangeni South Africa
Good Day,

Can someone offer an explanation on the below.

I roast on a Diedrich IR5. I follow a strict warm up procedure, I record the outside air temp, humidity and air pressure. I record every roast on Artisan.

Normally when I charge the roaster with green beans I do so when the BT reading reaches a certain temp say 215 C. The recorded ET at this point is usually +- 10 C lower. Two days ago I roasted with normal weather conditions (warm and humid) and nothing out of the ordinary with regards to batch weight, bean type, weather etc. To myself surprise the ET was the same as the BT at charge resulting in a noticeably faster and hotter roast. Today I adjusted my settings to accommodate for the change only to find that the ET was back to being around 10 C cooler resulting in a much slower and almost stalled roast.

I have no explanation.

Thank you
 

Musicphan

Active member
May 11, 2014
1,517
6
Kansas City
Thank you,

If you have the time, could you suggest / explain a bit more.

Regards Lawrence

Sorry - been crazy busy trying to pivot my business to 100% retail/mailorder. I was simply stating if that all of your key environmental variables are constant than its most likely something with your machine. I do find that if there drastic differences in weather conditions I see slight differences, but not significant. Primarily when its rainy my roasts tend to be slightly slower roasting and I need a bit of energy. However, since you said the environmental information is fairly similar as I would say its something within your machine. Either the gas pressure has changed - my USRC 12K runs on very low pressure so I doubt that it would be that issue, but possible. Or most likely, there has been a change to your airflow within the roaster. On my machine the ET is in a higher position than the ET probe and since heat rises it's always hotter. Since your ET was the same as the BT I would make the assumption that your airflow rate is higher causing it to drop.
 
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Law104

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Jun 20, 2019
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Empangeni South Africa
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Musicphan thank you,

I also think that the issue is within the roaster. I have made contact with Diedrich and I am still waiting for a reply from their engineers. I will pass on the feedback if I receive any.

Regards............
 

almico

New member
Feb 17, 2015
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Something changed. You need to find it. As has been said, it sounds like airflow. I've never used a Deidrich, but the airflow is a bit funky. It switches from flowing through he drum to flowing through the cooling bin and halfway in between, I believe. Could also be a dirty exhaust. Also, if they are the stock 5-6mm temperature probes, I would recommend replacing them with 3mm probes. Remember, the readings you get in Artisan do not represent the ET and BT. They represent the temperature of the probes. And all probes are not created equal.
 
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Law104

New member
Jun 20, 2019
27
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Empangeni South Africa
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Something changed. You need to find it. As has been said, it sounds like airflow. I've never used a Deidrich, but the airflow is a bit funky. It switches from flowing through he drum to flowing through the cooling bin and halfway in between, I believe. Could also be a dirty exhaust. Also, if they are the stock 5-6mm temperature probes, I would recommend replacing them with 3mm probes. Remember, the readings you get in Artisan do not represent the ET and BT. They represent the temperature of the probes. And all probes are not created equal.

Thank you I am going to inquire what probes are in the machine. Can I simply measure the probe diameter? I will reply.
 
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