Replies to This Discussion

Permalink Reply by Michael McIntyre on December 18, 2013 at 8:25am

What are your batch sizes, charge temps, and total roast times?

I have used an IR 3 and an IR 24 and have found that for really even roasts, particularly less than 16+ minutes, 80 percent of the rated capacity is optimum.

I have also seen that really dense, washed coffees can handle much more intense heat through the drying phase. When I want to roast a softer natural in 13 to 14 minutes, I'll often start at a higher charge temp, but keep the gas more gentle.

• ▶ Reply

Permalink Reply by T on December 18, 2013 at 4:55pm

I'm roasting 15# batches, charged at 425' and finishing at or under 15 min. 305' around 6:00 min, 1st crack in the 10:20 - 10:40 range.
I also have an IR 3 and hear what you are saying about 80%. I fill that thing right up and it loves it! I was trying not to roast 20# batches, but feel that may be the way to go.
The coffee is cupping well, but I know I can do better and seeing signs of tipping makes me want to tweak something just not sure what.

• ▶ Reply

Permalink Reply by Michael McIntyre on December 19, 2013 at 11:45am

I've experienced some scorch marks with smaller batches on the IR24 by having too hot of a charge temp and being either too aggressive with heat through the yellow stage or toward the end of a roast, trying to bring up my curve with too dramatic of a finish. We were looking for a turnaround at about 180 degrees, 300 at 5 to 6.5 minutes depending on coffee, and 1st crack at anywhere between 9.5 to 12 minutes. We were able to tame the roast defects by manipulating charge temp and heat intensity at these different stages. Also, we ran airflow as follows: through cooling bin until 300, where we would run air through the drum for 30 seconds to a minute, depending on the coffee, put it at 50/50 until 390, where we would run air through the drum until the end.

T said:

I'm roasting 15# batches, charged at 425' and finishing at or under 15 min. 305' around 6:00 min, 1st crack in the 10:20 - 10:40 range.
I also have an IR 3 and hear what you are saying about 80%. I fill that thing right up and it loves it! I was trying not to roast 20# batches, but feel that may be the way to go.
The coffee is cupping well, but I know I can do better and seeing signs of tipping makes me want to tweak something just not sure what.

• ▶ Reply

Permalink Reply by Jed Vander Zanden on April 17, 2014 at 10:24am

Great tips. I'm finding some darkened spots around 320 (where the beans contact the drum). Also running 15# batches and dropping around 420.

My big issue is my bottomout. I'll drop in and give it high-ish gas for the first minute or longer and will still be at about 160-165. I'd like to see it above 170 so there's not such a hill to climb.

• ▶ Reply

▶ Reply to Discussion