Ok. This is my first roast with my new BC-1. Some Papua New Guinea Arokara from Bodhi Leaf. Looking for some feedback and some guidance on how to do better. I pre-heated to 400F at about 2.3KPA. At 400, I cut the heat and air flow (AF). At 350, I charged half pound of beans, waited 30 seconds and then hit the heat and AF. AF was at 25% and I dialed back the heat to 1.2KPA through drying.

After Drying, I dialed back to 1.0KPA. At this point, not quite sure where or when to adjust AF in fear of stalling the roast. I dropped after 1C was over as indicated by my graph. I'm guessing I don't want that dip that shows in my ROR around the 8 minute mark, nor that slight raise. I was messing a little with heat and AF.

Thanks!

William

I have a BC-5 and typically run it at 3-3.5lb, which is about 60-70% of the roaster capacity. I usually heat the roaster to 450F let it come down to nearly 300F then back to 450F as it takes awhile for the roaster to warm up. It takes about 10-15 minutes before I drop the first batch. My first batch is very small, and I use it to ensure the roaster is warmed up. It would be the same principle but at a different scale, using 60-70% capacity for your roaster.
I typically drop the beans at 350F and 1.5KPA with the manual damper set to 3. I look at both BT and RoR and try to anticipate when the BT hits 300F and keep my eye on the RoR not to drop too fast. I also look ahead at the total roast time to see if I overshoot or undershoot. From your graph, it appears that your RoR dropped too fast in the middle of the roast. During the roast, I typically make continuous manual adjustments to both the gas valve and manual damper and give it a couple of seconds to see how it affects the RoR and BT. I don't make abrupt changes to either fan nor gas valve, but I always try to ensure that I have enough power to finish the roast.
It takes time to get used to a new gas roaster, I've had mine for a few months now and I'm still learning. Do a few roast to see how your roaster responds to small changes in gas valve and manual damper and you'll learn it in no time.

Here is a roast I did today, it was 3 lb Brazil. As you can see I'm still learning.

blondica73 wrote:I have a BC-5 and typically run it at 3-3.5lb, which is about 60-70% of the roaster capacity. I usually heat the roaster to 450F let it come down to nearly 300F then back to 450F as it takes awhile for the roaster to warm up. It takes about 10-15 minutes before I drop the first batch. My first batch is very small, and I use it to ensure the roaster is warmed up. It would be the same principle but at a different scale, using 60-70% capacity for your roaster.
I typically drop the beans at 350F and 1.5KPA with the manual damper set to 3. I look at both BT and RoR and try to anticipate when the BT hits 300F and keep my eye on the RoR not to drop too fast. I also look ahead at the total roast time to see if I overshoot or undershoot. From your graph, it appears that your RoR dropped too fast in the middle of the roast. During the roast, I typically make continuous manual adjustments to both the gas valve and manual damper and give it a couple of seconds to see how it affects the RoR and BT. I don't make abrupt changes to either fan nor gas valve, but I always try to ensure that I have enough power to finish the roast.
It takes time to get used to a new gas roaster, I've had mine for a few months now and I'm still learning. Do a few roast to see how your roaster responds to small changes in gas valve and manual damper and you'll learn it in no time.

Here is a roast I did today, it was 3 lb Brazil. As you can see I'm still learning.
<image>

Thanks! How long do you keep at 1.5KPa? Do you punch the gas after drying ends and then bleed to slow things down a bit just prior to 1C?

I really don't have a set time until I keep the 1.5KPa steady, it depends on how the BT and RoR behave. I do increase air flow slowly after drying to reach 7 on the manual damper by the time I pass through FC.

If you compare Christians graph and yours, one big difference is the gap or delta between BT and ET. A larger delta is going to apply more heat to the beans, and it's worth a try to do this in the beginning of the roast right around the turning point. With my small gas machine I shoot for a turning point of @ 80-97*C and either turn the gas down low or off after charging.

Try turning the gas up to the max and air flow to low at the TP and engaging the projected LCD's as Christian noted. I don't do this all the time, but it's one way to follow a declining ROR strategy. At the EOD point I start reducing heat and adding in some more air.

The idea behind this is to drive the maximum amount of heat earlier in the roast, then taper down to the end.

One thing I wonder about the comparison of profiles to Christian's BC-5 is that with the 3-3.5lb charge, his BT may truly be in the bean mass, whereas with the BC-1, where the BT is located(even on the left side) it seems it may be in the "bean-dropping flow" (if that makes sense). So it may still have a lot of hotter air temperature influence keeping the BT temperature higher than it would in the BC-5. That "bean-dropping flow" is something I saw here in a video or photo where someone had taken one of these small drum roasters (a Huky IIRC) and put on a plexiglass front plate to see the bean flow. I'll put in a link if I find it. It gave good insight to the bean mass dynamics of these smaller roasters/charges.

I found it ... hah! It was linked by Madman13 Josh in your BC-1 arrival thread:

See how the beans are kind of falling over the probe. And that's a full 500g charge. There's certainly a lot more hot air in the dropping phase than in the lifting phase.

I see what your saying about the ET thermocouple being wonky, and that might explain the unusual drop. Even still William could charge at a lower temperature, wait for the turning point, and then crank up to heat to max. The first time I tried this was with a 2013 Huky, just because it came with a 4kPa regulator and why not see what happens?

This Huky profile ended up being a "4,3,2,1 kPa" stepping down the high heat in 10*c intervals starting at 150c. (150c,160c,170c,180c)

Good stuff! Some good strategies to try on my roasts. I will report back.

William

William, are you cranking the fan speed and throttling airflow with the damper? Just curious since the airflow has the two control options.

Hi Jim,

To use the manual damper, you put the electronic at max (100%). AF is then controlled by the manual damper. I'm still working on watching where things are (ROR) and where the beans are at as to where air flow should be. A definite skill to be sure!!!

William