Diedrich IR-24K Coffee Roaster

Recently (March 2014) we acquired our first commercial roaster.  It was manufactured in 1994 at the Diedrich plant in Sandpoint Idaho.  This type of roaster uses infrared heat instead of traditional open flame.  This results in much greater efficiency and also less emissions.  A local coffee shop and roasting company had closed their retail doors and it as luck would have it they no longer used or needed the machine.  It was lacking a motor, fan, and the shroud encasing the fan.  In addition it was really really dirty.  Here are some before shots while it was still at the old location.



Large amount of creosote build up in the interior piping



Coffee oils built up under cooling tray

Cleaning took a lot, the coffee oils were built up so much that regular cleaning methods were of little use.  W would recommend a wire brush, flat head screwdrivers, and some steel wool for large build ups.


Wire brush was very helpful

The roaster without cooling tray weighs roughly 1000 pounds.  Moving it took a few piano dollies, a truck with a lift gate, and 5-6 people.  In the end not as big of issue as originally anticipated.


The roaster was in pretty rough shape and in need of some serious cleaning.  I don’t think the chimney stack had ever been cleaned.

IMG_6809 IMG_6814


This is actually pretty dangerous and can lead to a fire.  Clogging of the airflow can also lead to back pressure on the system and small explosions on the infrared burners used in Diedrich coffee roasters.

Here are some pictures after the cleaning.


We we’re missing a critical piece of the roaster, the exhaust fan, motor, and the piece that covers the fan (shroud).  We were able to order the motor and fan from Diedrich who were super helpful in the whole process.  Unfortunately the shroud was a piece specifically built for each machine and therefore unavailable.  Luckily we were able to get the dimensions from Melissa at Bluecaf Coffee Roasters and our man Jon built the shroud for us in no time.



Proper airflow is critical in roasting coffee, this roaster came with an 8″ straight steel pipe and 12″ insulated class A piping as a heat shield and fire barrier.  In order to vent this machine we needed to break through a brick and cement wall, run the pipe up a hallway and through the roof.  Each step seemingly harder than the next.


The brick wall

oh nice, the brick wall has a concrete wall behind it

oh nice, the brick wall has a concrete wall behind it


non issue


Oh look whats in the ceiling; an asbestos lined pipe !


safety first



Dwayne fitting the flashing


No turning back now


IMG_8062 Acme welding does it right




not a bad view at all




flame on

It took a lot longer to install than we had originally planned and after quite a bit of work it finally came together