All Diedrich owners

[muzoon]

Hi
I was recently working for 1 week with Diedrich IR12 coffee roster In Bolivia to help local coffee producers to profile their coffee roasting. But we had one issue with the roaster. It was scorching the beans.
We measured the drum rotation speed and it was making 30 revolutions per one minute.

IS that normal for Diedrich Coffee Roasters that the drum is rotating that slow OR should it be rotating faster?

Pleas let me know how many rotations does Your Diedrich Roasters drum is making during one minute.

Looking Forward to hear Your comments!

Thanks and will appreciate Your feedback!

 

[ElPugDiablo]

I have an older IR12, its rpm is 34. I don't have scorching issue. How close are the flame tiles to the drum? How many pounds/kgs are you roasting, and what is your charging temperature?

 

[muzoon]

Well, the burner is infra-red burner and is quit close to drum (may-be 2-3 cm).
We charged 10kg and starting temp. was 220 C.
220C was chosen to avoid roasting times to get too long.

So, 30-35 revolutions per minute is ok on Diedrich roasters.

 

[ElPugDiablo]

I usually roast no more than 7kg per batch and charge from 200C to 215C and don't have any problem. How are you setting your airflow? Also my is an older model which known for being under power, if your roaster is less than 5 years my experience my not be applicable to you.

 

[muzoon]

the Diedrich is 10 years old and this is good to know that they have changed some things like stronger airflow in 2005. What else? I would be happy to know!
as I was roasting with diedrich for the first time I set the airflow 50/50 and during cracks to full drum. I was told it was recommended like this in user manual. at the same time i had not enough time to experiment fully cause I had to fix their way of roasting (backing actually [25:45 min for esp.]) I used 10 kg cause I use that amount as max on my L12 Probat.

As I understand the scorching may happen because of too high charging temp. and may-be too low airflow?
at the same time we charge coffee on high temps on our probat too but there is no such scorches, parts of beans. in diedrich beans look like they where roasted on pan not in rotating drum. Probat drum rotates 1 round per second which is almost twice the speed. beans fly around in the probat drum. In diedrich they seam to be more in contact with surface of drum.

It was interesting to see how was diedrich airflow system was built comparing to probat. it only sucks air from the drum but not through the drum as it is with probats. I had a question: from where the air gets into the drum which is sucked out into exhaust? only answer I was able to think of is: all the small fissures and holes are the places(?)

What are the exact differences between older and newer diedrich models?

I would be happy to get any knowledge on Diedrich roasters

Have you any idea where would it be possible to get a copy of diedrich IR roasters owners manual except diedrich company itself?

thanks and looking forward

 

[Thunder]

I was burning batches at first, until I realized that my I-12 was set up for Natural Gas, though I was using LP. I bought/installed the converter kit, and it worked great. Good Luck.

 

[paulc]

I just joined this forum and see that no one answered your question about how air gets into the roasting drum. I also made the same assumptions you did until I got educated by Jason at Diedrich. On an IR-12, most of the air enters the roasting drum through the front hopper. If you remove the front hopper you will see that there are 2 holes in the front plate. The upper hole is above the drum and the lower hole leads into the drum. Air enters the roaster and is heated by the heat sinks around the drum it then travels out the front plat and into the hopper. From there it reenters the roaster into the drum.