Some more brewing notes added. I'll have time to run a few more/different profiles tonight. The coffee has a lot of hang time, it's still improving, less boozy and brandy like.

A couple of people have mentioned the savory aspect of this coffee. In my roasts so far, I experience this in the cup, but not so much in fragrance or aroma. To me, in my three roasts so far, I find this aspect unpleasant -- more like sweaty socks than herbal or broth-like. The least offensive of my roasts is the one that was taken all the way to early 2c. Does anyone have ideas of how I might get a city or city+ roast while avoiding the funk? I'm roasting with a popper, modified so I can control the profile.

Patrick,

I noticed you roast with the KapoK 500. Any thoughts on this roaster?

Thanks and happy roasting!

Henry

Hi Henry,

I had been lurking for years, and finally decided to pull the trigger on this one.

The un-boxing and the first impression is chronically logged in GCBC (http://www.greencoffeebuyingclub.com/in ... ic=18753.0 ; require registering to read). Hank (hankua) marvelously reorganized my scattered thoughts and paragraphs, and now you can also read my experience on his blog (http://hankua.wordpress.com/2015/01/15/ ... e-roaster/ ).

I'm new to gas roasting, and still exploring the potential of this machine. As a newbie, I don't know where to look, what to ask, but I'm as curious as you are. Please feel free to ask me anything, and I'll do my best to find out the answer. We can resurrect the old thread KapoK roaster for further discussion.

Cheers,

Patrick

Andy wrote:A couple of people have mentioned the savory aspect of this coffee. In my roasts so far, I experience this in the cup, but not so much in fragrance or aroma. To me, in my three roasts so far, I find this aspect unpleasant -- more like sweaty socks than herbal or broth-like. The least offensive of my roasts is the one that was taken all the way to early 2c. Does anyone have ideas of how I might get a city or city+ roast while avoiding the funk? I'm roasting with a popper, modified so I can control the profile.

It seems to me that these beans can take a lot of heat. I have three distinct profiles in mind, but so far can only successfully execute one.

The first one is the high charge temperature, fast roasting (10-min) profile, as shown in my batch #4. IMO, this profile may preserve the most fragrance. These Rwanda beans are best with the rest time from day 6 to day 11 in this profile.

The second one is the long drying phase, fast ramp profile. I'm still working on this one.

The third one is called "gliding". After hitting target temperature, controls power/fan to maintain at this
temperature for couple more minutes before dropping. It is said to remove funky smells/tastes in light roast.

9Sbeans wrote:It seems to me that these beans can take a lot of heat. I have three distinct profiles in mind, but so far can only successfully execute one

...

Thanks. That gives me some ideas to try. Glad I got enough of this bean to experiment with. There is a lot to like about it; I think it will be great if I can tone down the bit of weirdness I have been experiencing.

TomC wrote:These espresso shots are like brandy. It's certainly something different. Should be fun to play with in a melange.

Any luck with the melange?

I used to blend 10~14-days rest, lighter roasted beans with 6~10-days rest, darker roasted beans to make espresso. I have tried cross-blending my earlier lighter roasted Rwanda with the later, darker roasted ones. The results were good, but not exciting. I feel it lacks a "central scene", be it fruits, body, or chocolate. It's a well-rounded cup, but I haven't found out the focus to be emphasized.

Three more batches. Just for fun, don't know how it will taste next week.


Roasting Info:

Bean: Rwanda Karongi Gitesi #5 Flat RoR
Roaster: KapoK 500 sample roaster
Charge Mass: 227.1 g
Charge Temp: 297.5F
Dry/Ramp/Development: 5:54/4:30/2:12
FC-start temp: 374.7F
Finish Temp: 404.8F
Overall Roast Time: 12:37
Weight Loss: 13.78%

---


Roasting Info:

Bean: Rwanda Karongi Gitesi #6 Slow Start Fast Finish
Roaster: KapoK 500 sample roaster
Charge Mass: 227.0 g
Charge Temp: 299.7F
Dry/Ramp/Development: 5:51/3:39/2:11
FC-start temp: 376.3F
Finish Temp: 410.2F
Overall Roast Time: 11:42
Weight Loss: 13.96%

---


Roasting Info:

Bean: Rwanda Karongi Gitesi #7 Gliding
Roaster: KapoK 500 sample roaster
Charge Mass: 227.1 g
Charge Temp: 352.8F
Dry/Ramp/Development: 3:39/4:02/4:17
FC-start temp: 379.0F
Finish Temp: 393.6F
Overall Roast Time: 11:59
Weight Loss: 14.88%

___

2/24 updated:

Day 6 post roast, I did a non-scientific, lots-of-fun tasting test of batches #5, #6, and #7 with my colleagues. I included a positive control, Ethiopia Gedeo Yirga Cheffe, and randomly labeled them in A, B, C and D. My idea is that a person should be firstly single out this distinct origin, and then I could ask s/he a simple follow up question, choosing the most favorite/dislike cup. If a person cannot pickup the positive control, s/he might not like any of the black coffee, not test all of them, or just not care. I also included a positive control (Guatemala Gesha) with my previous batch #1 and #2 test.

The results were striking. I got 7 votes favoring Ethiopia Yirga Cheffe, 2 vote for #5, 3 votes for #7, and 1 dislike the sour after taste of #6. Ahhh, so much telling for roasting profiles. What is the old saying? If one cannot determine the optimal roasting profiles for a certain bean, the best approach is to try a different bean.

Due to the time constrain, I couldn't ask advance questions in this big group. I'll improve my assay method next time.

___

2/28 updated:

My profiles #5 and #6 are similar in the Drying & Development phases, #6 has fast Ramp. Both batches matured at similar rates, and exhibited similar fragrances/tastes. Day 7, the espresso was plain. The #6 had more herbal and acidic, but it stimulated more at the front of the tongue. Day 10 & 11, both batches got enough rest, and really shine in the cup. #6 (fast ramp) always preserved more high notes and the herbal flavor comparing to #5 (flat RoR) during these days, and #6 fast ramp developed a more pronounced sweet-aftertaste.

My batch #4 employed the high charge temperature, fast start slow finish profiles, and peaked at day 8&9, and it made really exciting SO espresso (of my taste). After day 10 this batch decayed fast (most of my batch #4 was gone by this time, only few left to test).

Batch #5 (Flat RoR) preserved fairly good origin herbal flavors, and steadily showed a balanced cup during all these days. However, it never became the bean of the choice during any of these days.

Batch #6 (Slow Start, Fast Ramp) had more acidic and high notes than #5. It was unbalanced at day 6 & 7. After longer rest time, it made decent espresso. It didn't reach the exciting peak as the #4, but it presented quite a balanced origin (herbal) & roast flavors. The espresso was good from hot to cool. If I want longer shelf life (e.g. 2 weeks) for espresso roast, I would choose this profile.

Batch #7 (Fast Start Slow Finish, 2min Gliding) was a fun experiment trying to mimic a profile from 2014 WCE roasting contestant, Björn Aarts. The archives can be accessed here: http://www.cropster.com/world-coffee-ro ... ion-finals


As can be seen in the above profiles, the power was reduced to minimum after reaching the target temperature, and the beans were kept in the drum for an extended time at an almost constant temperature.

The Gliding is said to reduce excess acidity and funky fragrances. In this attempt, I tried 2mins of Gliding at the end of the first crack. The drop temperature was relatively low, but the Gliding seemed to effectively remove the moisture content and it had greater % of weight loss.

As expected, the herbal taste was all gone, and there was a bitter-sweet aftertaste in SO espresso. It was a comfortable cup, and should make a very good milk based drink. However, imo, it was featureless and less interesting. 2mins of gliding might have killed all of the high notes. If I want to play with the Gliding next time, I would try a light roast with 1min of gliding, and limit the overall development time in around 2:30 range.

Another aspect is that, in Björn's profiles, the ET is higher than BT, and the Gliding quickly reduces the ET whiles ET is still greater than BT. In my profiles, ET & BT already converged after the first crack, and the Gliding makes ET significantly dropped below BT. I'm not sure if it has the potential of stalling the beans, and I'll pay extra attention next time.

Here are the notes from my first roast:

--

Roasting Info:

Bean: Rwanda Karongi Gitesi
Roaster: USRC Sample Roaster
Charge Mass: 400g
Charge Temp: 325F
Dry/Ramp/Development:4:45/3:30/2:45
FC-start temp: 375F
Finish Temp: 394F
Overall Roast Time: 11:01
Moisture Loss: 15%

Profile Plot:



[BT=Red, Exhaust=Green, Gas=Blue, Fan=Yellow]

Cupping Notes:

Rest: 4 days
Brewer: v60-01
Grinder: Bunn w/ Ditting Burrs
Water: 250ml, 205F
Coffee: 16.5g

Dry Fragrance: Bakers chocolate, roasting spices, dried cherries

Wet Aroma: Chocolate cake, pipe tobacco, raspberries, cream. Very rich!

Warm taste: Brandy, sweet cherries, tobacco & cocoa, milky body, lingering sweet tart aftertaste.

Cool cup: Cherry brandy, still quite sweet, but with a faint hint of chives starting to creep in to the aftertaste.

Overall Impression: This first cup has a lovely fragrance and aroma, and it tastes great while hot, but that vegetal hint that emerges in the cool cup is pretty off-putting. I don't think this is underdevelopment, because I actually took this a little deeper than my typical brewing roast. I suppose it might just be a few "off" beans; if it goes away in subsequent cuppings, I'll post back to let you all know.

I may try a slower, deeper roast to see if that moderates this aspect of the taste, especially since this green has plenty of acidity to spare.

Added at 6:30 PM on 2/18: This evening I tried pulling a shot using some coffee from the same roasting batch I describe above. I pulled it medium-hot on the Caferina, using 9g of coffee in the single basket to pull a 36g lungo. There was still something vegetal in this shot, but it had morphed towards a pleasant hint of roasting herbs, which mingled reasonably well with the flavors of chocolate, leather, bourbon, and raisins that the shot presented. The whole combination reminded me a bit of some of the odd combinations of savory/sweet flavors that one finds in amari liqueurs. Definitely not a breakfast shot, but more something that would be nice to offer guests after dinner.

[creative nickname] wrote:This first cup has a lovely fragrance and aroma, and it tastes great while hot, but that vegetal hint that emerges in the cool cup is pretty off-putting. I don't think this is underdevelopment, because I actually took this a little deeper than my typical brewing roast).

For what it's worth, I've definitely noticed that vegetal element and it's quite distinct from the off-flavor contributed by underdevelopment. It's just part of the coffee and not terribly intrusive.

Also, my post will be updated shortly with espresso notes and more profiles - this time two approaches for espresso.