Diedrich troubles...

Raf

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Feb 12, 2009
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Hello,
I just took over roasting for a small coffee shop and the machine is a Diedrich IRC-7. For the last couple months I've been working like crazy to get the roast times down without much luck. The machine is close to 10 years old and no one can tell me much about it. This leads me to a very basic question: Does the IRC-7 utilize infrared technology? Or rather, should the IRC-7 be utilizing infrared technology?
I've found mentions of it being infrared online but my machine clearly has normal gas burners.
Thanks!
Raf
 
i took over for the shop i manage a few weeks ago, we are using a deidrich ir3 believe it has the ir barrel heaters from what i am told. I am getting 18-23 minute roast times. Im not trained on the machine so i have trouble controling the heat. I mean the coffee that is coming out is acceptable to my customers they actually love it compared to the dockstreet and ellis products we used to have.
 
I've roasted exclusively on Diedrich Roasters, not by choice, for ten years. I suggest taking a roasting course through Deidrich, since you own one of their machines. They're in a beautiful small town in northern Idaho called Sandpoint. Knowledgeable staff, I learned a lot, and treated it as an investment in the company.
I learned Stephen Diedrich's way, but still continued to experiment with different roast times, temperatures, and momentum variations. Learning from Stephen Diedrich is a great way to learn about roasting coffee correctly.

mpdavis said:
i took over for the shop i manage a few weeks ago, we are using a deidrich ir3 believe it has the ir barrel heaters from what i am told. I am getting 18-23 minute roast times. Im not trained on the machine so i have trouble controling the heat. I mean the coffee that is coming out is acceptable to my customers they actually love it compared to the dockstreet and ellis products we used to have.
 
Its awesome if your customers like it. I feel you'll get optimum flavor out of a 14 to 15 minute roast. 18 to 23 minute roast take longer which roasts out a lot of the moisture in the bean, leaving a somewhat, "baked" flavor. Try loading the raw coffee beans at a higher temperature, maybe around 440F. This should give you enough momentum to achieve shorter roast times. You also must know how to adjust the flame accordingly. I would go through the cracks at a much slower rate, and remember, roasting doesn't truly begin until 200Celcius, or about 382F. If you can get to the 1st crack at about 9 to 10 minutes, you may just hit your mark to finish the roast off at about 14 minutes. It's very important to back off the heat at the time of the cracks. Bean development is crucial. It doesn't hurt in experimenting with different roast times! It may just rocket your business.
 
Hello Mark,

Just reading some of your posts and it looks like you have some great knowledge. I am new to roasting and have not been super excited about the results.Results are ok and customers are liking the coffee. I know it can be better. I think I am roasting too long. The end flavor is ok, but not great. What are your coffee amounts when you are refferring to a ideal end roast of 14 min? I have a IR 12 and usually do 12-18 pound batches. I think I am getting the baked coffee result you were talking about but not totally sure? Can you elaborate on what you do w/ the airflow and flame before and at 1st crack. I have been leaving the airflow at the full roasting bin setting for the entire roast cycle due to the fact that I have heard the airflow can be weak on the diedrichs. My Diedrich is 14 years old, but never used until this last march. I know! Weird huh? I was excited to buy it.
Thanks for your time.
 
Timing the airflow on a Diedrich is crucial. I have an IR-3 and there is a handle to shift the airflow from cooling tray to barrel...must be done closely following the manufacturer's recommendation. This basically shifts the air in the roasting chamber to keep the optimal ambient temperature and air flow, but also allows the operator to blow off chaff at critical times during the roast.

I am pretty sure all of the IR roasters use the same "tiles" to roast. Mine uses a propane flame to heat the tiles, but it's the tiles that roast the coffee - they spread the heat evenly as opposed to direct flame exposure. Thus the "infrared" roasting technique. I think of it more as radiant-heat roasting...but whatever.

At first I was concerned about the beans baking instead of roasting...but having mastered the process I can say the results are excellent and the customers love it. That in itself is satisfaction enough for me!

My best advice is to contact the company. Sandpoint, Idaho, is a long haul for me, but if you are closer you should consider making the trip to take a roasting course with them. Worst case, call them and talk it over. If you don't have a manual for your roaster, I'm sure they'll send a copy.

In a pre-heated roaster and following manufacturer's specs, my roast times are usually dead-on at 14 minutes for a medium roast, slightly longer (maybe 17 min) for darker French or Espresso roasts. It is important to pre-heat the chamber before you drop the beans...those tiles need to get up to temperature to really work effectively.

I have to admit, my IR-3 is the most energy efficient roaster I have ever worked with. It is also very easy to clean and service. The folks at Diedrich have been very helpful and professional as I got up to speed on operating this roaster.
 
Air flow will make and break good roast. It's best to place your air flow at "through roasting drum" during the cracks. Otherwise your beans will have too much gas pressure built up inside the drum, leaving no room for bean development. The gases being dispersed through exothermic reactions from the roast need a place to escape. Thus Air flow needs to be set at "Through Roasting Drum".

You should do little with the flame during roasting. I have my flame set at where it should be throughout the entire roast. A full batch should be set at high, a medium batch should be set at half the flame respectively. There are certain temperatures you need to be at certain times during the roast. Once you get into the second crack, you should have enough momentum to carry you until the roast is finished so shut it off. During the end of the roast, the beans begin to disperse heat rather than absorb it, so you want to be gentle on the heat at the end. Play with it, and aim for that 14 - 15 min mark, for an amber colored roast, without any oils bleeding the surface.
 
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