The real deal pros and cons, Diedrich Probat, and how the tech has evolved


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Sep 17, 2008
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There have to be other people out there trying to decide on a brand of roaster. The typical argument is that there is no "best" but it comes down to preference and needs.

Some of the technical and operational principles are available. For example,

Diedrich roasters utilize infrared heating elements to create convection heat via indirect heating of the drum. Ambient air is brought around the drum and heated up before making it's way into the bean mass. Advertised advantages are, no exhaust fumes contacting the beans, no "hot spots", less energy, consistency. Usually steel drums.

Probat roasters use and open atmospheric style burner that does not directly touch the drum, yet is diffused over a type of steel plate that also is an inlet for air and creates hot airflow around the outside of the drum then into it. The advantage I hear about is, faster response time on the profile due to extra BTU power. A cast iron drum usually, from what i understand, there was a long period of production years that used steel instead of cast iron, but now it's back to cast iron with the newest roasters.

I've read and meet roasters that say you can not roast on a probat while beans are cooling off. I have a hard time understanding this because on a diedrich, it is advised to roast in the first several minutes with minimal airflow (still 20%+-) and then to open it up at other points depending on your style, but it is intended to roast continuously while cooling simultaneously. I've seen probat profiles with 100% airflow the entire roast, this seems like standard operating procedure. I've also read that they tend to have lower overall airflow.

I mentioned this to a probat roaster and he had never heard of this idea.

Newer probats have two seperate motors, one for the drum airflow and a separate one for chaff collection, now claiming to be able to roast and cool at the same time.

New diedrichs seem to have improved ergonomics for roasting over the years but little else is apparently different.

These are some of the things that come to mind, but then how does this translate into the cup? All these differences, but I am really trying to get a grasp for how these things can effect the flavor development. And some real pros and cons.

I've been roasting on a diedrich for a solid two years. I'm interested in upgrading to a larger roaster, I have been fascinated by Probat and would really like to learn more about the differences.

From Klatch, I have tried some good coffees, but I've had super coffees in the acidity category as well as from the sweeter full bodied category and great espresso. But the same can be said about roasters using probats. If anyone want's to chime in that has some experience please chime in!