Three more batches.
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Roasting Info:

Bean: Ethiopia Yirga Cheffe Gedeo, Batch #4, 300F Nordic trial 400F
Roaster: KapoK 500 sample roaster
Charge Mass: 227.0 g
Charge Temp: 300.4F
Dry/Ramp/Development: 4:42/3:30/1:20
FC-start temp: 378.9F
Finish Temp: 399.9F
Overall Roast Time: 9:33
Weight Loss: 12.11%



Charged at 300F, power adjustments of batch #4 was similar to that of batch #1 prior of first crack, carrying momentums into 1C, but dropped while first crack rolling. I applied more air flow in the early phases, and gradually reduced it. Don't have a good Nordic style template to follow: high/low momentum to enter the first crack? Stretching/dragging for how long? Air flow adjustments? Just messing around and will see the results in a week.


***

Roasting Info:

Bean: Ethiopia Yirga Cheffe Gedeo, Batch #5, 299F Rao Full City trial 419F
Roaster: KapoK 500 sample roaster
Charge Mass: 227.1 g
Charge Temp: 299.4F
Dry/Ramp/Development: 4:36/3:37/2:20
FC-start temp: 380.3F
Finish Temp: 419.2F
Overall Roast Time: 10:34
Weight Loss: 14.53%



Charged at 300F, power adjustments of batch #5 was similar to that of batch #1 before first crack. I have seen many larger drum roasters using this approach: building up tremendous momentum during the ramp phase, and subsequently coasting through the development phase. In my 500-g sample roaster, I don't have the luxury stable thermal mass as those big boys. I may need more subtle adjustments to compensate the bean/weather variations. Anyhow, I need the momentum to reach full city range (usually I won't go to FC) on time. This is a trial to follow Rao's rule and extend it into the dark side. I reduced the power several times during the development phase, but apparently still couldn't prevent the flick at the very end.

***

Roasting Info:

Bean: Ethiopia Yirga Cheffe Gedeo, Batch #6, 355F Rao +---- 397F
Roaster: KapoK 500 sample roaster
Charge Mass: 227.0 g
Charge Temp: 354.9F
Dry/Ramp/Development: 3:32/3:31/2:18
FC-start temp: 379.9F
Finish Temp: 397.2F
Overall Roast Time: 9:22
Weight Loss: 13.30%



Batch #6 (similar to my batch #2) is my reference roasting profiles. Charging at high temperature, reducing heat during the roast, moderate air flow adjustments, gently entering the first crack, and drop the beans within the 20-secs sweet window. I ran slightly longer development phase on this batch than the batch #2.

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3/24 updated:

In my roaster, increasing ventilation fan speed within a common range (30-55%) slows down the RoR (while maintaining RoR positive). I used to aggressively increase my fan speed as a way to tune down RoR. However, excessive air flow during the late ramp and development phases may strip off volatile flavors in my settings, and I revered back to the gas adjustment as my major temperature controls. (also read: What does coffee taste like when you use too much airflow? ) I had no prior experience of the Nordic style roasting, and what I gathered was a higher-than-usual air in the early phase, hence I decided to give it a try.

I'm happy with my batch #4, the Nordic trial. It was not sour, but with a refreshing lemon zest and sweetness in my typical Aeropress routine (24g fine grinds: 250g 201F water; 30sec 50ml bloom, 35sec (150 + 50mL) brew, 30sec press).

My batch #5 was OK. The junction between city+ and full city was vague. I got more body and low notes, but no significant chocolate yet. My batch #6 was also fine. Without the side-by-side comparison, I couldn't tell significant difference between my batch #2 and #6. Both my batch #5 & 6 made decent SO espresso.

The fun part is mélange.

So far, I like 20% Nordic (#4) / 50% City+ (#1, #2, or #6) / 30% Full City (#5) combination. 20% of Nord provides sufficient citric, penetrating through the rich floral notes. I think Nord also added to a sweeter after taste. The Full City roast was a counter balance of Nord, and it extended the lower notes to a fuller spectrum. As I described in post #10, I liked the complexity of my batch #1 over batch #2. Blending (#4+1+5 vs. #4+2+5) greatly enhanced the complexity, and made both of them equally lovely.

I didn't try the acid bomb, due to the limitation of my equipment, imaging cranking Pharos for two double shots of Nordic roast, and pull the shot on a pump machine. Oh, well, one can dream.

Hey, it's been a while. I'm excited about this coffee. It was fun roasting and the aromas coming from the roaster were great.
Anyway, I'm roasting 151g batch sizes on The Quest M3. That was my standard batch size for the longest time, but (out of laziness ) I've been roasting 188g for a while. I only mention that because the first couple roasts went a bit faster than I expected. I lowered the charge temp to compensate, but the MET at charging was higher than I even hit for my larger batch sizes. It just goes to show how important monitoring MET is for the Quest.

Roast 1

I used Jim's roasting method (bean door open) for this roast. It is the most common roasting style I use. The drying phase went a bit faster than I wanted, but the rest of the roast went as expected. The only note worthy thing about this roast was how strong and prominent first crack came on. It was way more powerful then the remaining roasts tonight.


Higher Resolution Link

Roast 2

Same roasting method, but I lowered the charging temp to slow the drying phase. Unfortunately, it didn't really go that way. The MET was too high. I was trying to shed some heat so I basically cut power to the heating elements. It was to little to late for the drying phase, but slowed the ramp to first crack. Nearly 50% of the roast was the ramp. This will probably be the worst of the 3 roasts I did tonight, but time will tell.

Higher Resolution Link

Roast 3

I roasted with the bean door closed for this roast. I used moderate fan during drying (4) and 6 amps. For the ramp I maxed out the fan and ran the amp at around 8ish. If I could have changed anything for this roast, it would have been to slow things down a bit going into first crack. Anyway, I'm still happy with this roast and can't wait to brew it. I didn't save the chart before shutting down the computer . The roast was approximately 4:30 - 9:00 - 10:10 at 409F at drop.

If folks prefer, I'd love to see the ball continue rolling on this discussion. There's enough exciting dialogue to share that could easily last us thru April as well, and we can all really fine tune our profiles. Many times, a month (actually only about 3 weeks) isn't enough.

If folks don't have an objection, we can continue on with this bean thru April. Share your opinions here.

The exciting news for HB members is that Jim Schulman will be leading May's discussion

Roast Date: Mar 15
Roaster: Huky 500 w/perforated drum + 48RPM motor

Roast 1:
Charge - 227g
Final weight - 198g (12.8% loss)
Times - 3:39/3:48/1:42
Drop - 411F (city)
Dev ratio - 18%
Roast notes: TC's were spiky again so the RoR graph is poor, but hit declining RoR pretty well

Tasting notes (2 days post roast, aeropress): nicely balanced, decent body. Classic Yirg. Mix of citrus acidity and chocolate low notes, surprisingly. Should develop nicely over the next several days. Very slight florals.

3 days post roast: heavy florals and perfume. There that goes.

Roast 2:
Charge - 225g
Final weight - 194g (13.8% loss)
Times - 3:24/3:33/1:39
Drop - 411F (city)
Dev ratio - 19%
Roast notes: TC's were getting a little spiky so the RoR graph is junk, but hit declining RoR pretty well again. This was an attempt at a more nordic-style roast, but it ended up declining on me naturally a bit too much, and so was simply a hotter/faster version of roast 1.

Tasting notes (2 days post roast, aeropress): thinner and crisper than roast 1. No low chocloate notes. Pronounced florals and acidity.

TomC wrote:If folks prefer, I'd love to see the ball continue rolling on this discussion. There's enough exciting dialogue to share that could easily last us thru April as well, and we can all really fine tune our profiles. Many times, a month (actually only about 3 weeks) isn't enough.

If folks don't have an objection, we can continue on with this bean thru April. Share your opinions here.

The exciting news for HB members is that Jim Schulman will be leading May's discussion

Keep Gedeo going! It is a bean worthy of fine-tuning. And I am sure more interesting profiles are to come.

9Sbeans wrote:Huky and Quest have thin drum wall and may need to apply more heat in the beginning to achieve a high RoR.

Even within the Huky, the perf drum vs. solid drum have wildly different starts. On the hukyforum boards, we've been discussing it a lot.

With my Huky perforated drum, I have been charging with the heat on full blast and fan on med/high in order to get a fast start, and start ramping down at the 1 and 2 minute marks until 300F. If I don't blast it with heat at the start, I get very slow TPs and low initial RoR. The solid drum guys don't need to blast it like that.

pShoe wrote: I didn't save the chart before shutting down the computer . The roast was approximately 4:30 - 9:00 - 10:10 at 409F at drop.

Hi Paul,

Your roast 2 has longer (5:13) ramp phase. In theory, it will convert more monomer sugar into caramelized form. I've seen Tom (TomC) playing with the extended ramp time recently, and wondered the effect in the cup. (BTW, would the effect of the ramp time be tested/discussed in the Hoos' new book? ) You may want to modify the linked graph of your Roast 2 (it's showing the same picture as your roast 1).

There is an autosave function in Artisan: Config -> Autosave... check the Autosave box, specify the prefix of the filename and the default path. The raw data files (.alog) can be retrieved.

The font size in the graph is not adjustable by user. If you save the graph in full screen mode, the characters will be blurry and tiny after resizing of the graph. I get around of it by reducing the size of the window of Artisan before saving the graph. File -> Save Graph -> Full Size... save as .png For example, my screen resolution is 1920x1200, and the full screened Artisan will save graph into 1920x1018 dimensions (not recognizable after resizing). If I reduce the size of Artisan into a 900x800 window, it will produce a better graph.

I also change the scale of Axes to make my graph bigger: Config -> Axes... to modify the min/max values of the temperature axis as well as the DeltaBT/DeltaET axis.

Cheers.

jalpert wrote:Even within the Huky, the perf drum vs. solid drum have wildly different starts. On the hukyforum boards, we've been discussing it a lot.

With my Huky perforated drum, I have been charging with the heat on full blast and fan on med/high in order to get a fast start, and start ramping down at the 1 and 2 minute marks until 300F. If I don't blast it with heat at the start, I get very slow TPs and low initial RoR. The solid drum guys don't need to blast it like that.

Yep, the effects of airflow (perforated vs. solid drum) on roasting are uncharted territory.

TomC wrote:If folks prefer, I'd love to see the ball continue rolling on this discussion. There's enough exciting dialogue to share that could easily last us thru April as well, and we can all really fine tune our profiles. Many times, a month (actually only about 3 weeks) isn't enough.

If folks don't have an objection, we can continue on with this bean thru April. Share your opinions here.

The exciting news for HB members is that Jim Schulman will be leading May's discussion

Keep it going! I botched my first batches enough that I haven't posted notes yet, but have enough beans to go through the next month. Would love to keep it going.

9Sbeans wrote:Three more batches.
*...

Your Nordic and Rao roasts appear well executed, although your probe is slow so it's not possible to be sure of what's seen. I'd love to hear your tasting notes, though!