Kenya Nyeri AB Gatomboya

Kenya Nyeri AB Gatomboya

Farm Description

Gatomboya is a coffee washing station, a wet mill, a coffee factory. By "factory", it does NOT mean they make mugs, custom hats and vacuum bottles. A "factory" is a wet mill where the coop members bring coffee cherry for pulping, fermenting, washing, drying. It's not the factory as we might imagine it. Small washing stations are aligned with a particular "society" which is what they call a cooperative in Kenya. We had an incredible lot of Gatomboya a couple years ago year, which is part of the same cooperative group as Gaturiri: Barichu FCS. We notice have been buying from the same family of coffees lately, such as Barichu and Tekangu societies. This was one of the most expensive coffees from Kenya in the previous season when we bought it as well, sourced direct from the cooperative to secure it's purchase. We didn't want to risk entering the auction with a great coffee like this, but it also means we had to pay a premium to ensure the final cost was at or above what the auction price might be. Based on the cup, it was a smart move. As with all our Kenyas, this coffee ships in vacuum pack on it's rather long ocean voyage, which helps protect against the effects of humid maritime environments.

This coffee is part of our Farm Gate pricing program.

Cupping Notes

Caramel and cane sugar sweetness dominate the dry fragrance, with lush tropical fruit and grape notes. It develops a very nice chocolate and citrus scent even at relatively light roast levels. The wet aromatics add blackberry syrup to caramel, with fresh cream and cherry on top. The cup also has a creamy sweetness, peachy in the lighter roasts, while the Full City develops a black currant and baking spice flavor. The cup really opens up as it cools. The character of the fruit seems to depend greatly on the degree of roast, how long after roast the coffee is rested, and the temperature of the cup as it cools. But there is no question this has complex, clean fruit notes. Peach turns toward apple as the cup cools with hazelnut as a backdrop of lighter roasts, while it becomes more milk chocolate with darker levels. It's a bright Kenya for sure, but not over-the-top, so it can have broad appeal to a range of palates.

Score

90.2

Lot Size

80 Boxes

Roast Recommendations

City+ to Full City roast is ideal.

Processing

Wet Process

Varietal

SL-28    

Grade & Appearance

.2 d/300gr, 17-18 screen

Packaging

Vacuum Packed at Origin
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This coffee has sold out. The review is provided for reference purposes only.

Barichu sign at Gatomboya factory, Kenya

Coffee pulp in the washing channel

Peter with an old (and rather tired looking) SL-28 Bourbon tree.

Cupping Kenya lots in Nairobi
 

Comments

#1 Roasting advice

Hi. I recently purchased this coffee and would welcome any roasting advice. I'm a new roaster working on a new IR2.5. I roasted a couple of 2.5 lb green weight batches and curiously to me first crack was very weak. In my limited experience I noticed the green coffee is very hard according to my bite, and perhaps the hardness is the factor. One roast had a steep slope and the crack was weak but more pronounced than the other roast which was slower. In that roast, I received a few pops and that was it. For all other coffees I'm used to a crack that is about 1-1.5 min long and pretty robust. I'm excited about the coffee but I don't think so far it's as fruit expressive in the brew as I think it could be (dry aroma I'm picking up some lemon and peach I think). I pull samples too prior to dumping and assess the development. Anyway, I'm wondering if such a weak apparent crack is a sign I'm doing something wrong or if it's a signature of this coffee. Any any other tips would be appreciated. I take extensive data, cup, and have read the posted articles on stretching the roast. Thanks!

#2 Thanks so much for your

Thanks so much for your comment! Different coffees do have different densities, so it's not so uncommon for there to be different intensities of 1st crack. Can I ask you to give me a few more details? What are your total roast times? When does 1st crack start? how long after 1st are you dropping the beans? Also, What's your charge temp? If you are uncomfortable giving any of this information I totally understand, you can email me at chris@coffeeshrub.com, but I'd love to have this discussion here as it might be helpful for others.

#3 details

Here are the answers: two profiles so far w/common charge temps of 355. Profile 1= FC start at 9:45 at 365 degrees then dump at 14:00 at 392. Profile 2= FC start at 7:30 at 365 then dump at 11:15 at 392. My experience to date shows temperatures achieved at milestones are correlated to mass of a batch, so if I would have 4 lb in roaster instead of 2.5 lb, the final temp achieved would be higher. Note in Profile1, sample pulled at 13:00-13:20 was preferred by me compared to final dump coffee. Note with a coffee this hard I'd probably try next to raise charge to 365 but I've never experimented higher than that. Note I turn air to 50/50 at 285 and to Roaster at 330 generally. Thanks!!!

#4 so, a couple things right off

so, a couple things right off the bat. First of all, thanks for responding here, I love working these things out in this venue as, like I said, perhaps it can be helpful to others.

As far as the roasting parameters go:

- Most drum roasters operate the most efficiently at 75%-80% capacity, and definitely not more. Doing considerable less than this can lead to inaccurate probe readings, less probe contact with beans making it more of an environmental reading. That being said, I've done a number of 2.5lb batches in a IR3/2.5 and they were pretty even, but I think they worked better at 3.

- The time between 1st C and dump in batch 1 seems too long and you probably over-developed the coffee here, keeping it at this temp range for too long breaks down the chlorogenic acids and trigoneline, which lead to perceived acidity, dynamics, and fruited flavors in the cup.

- You definitely want a more vigorous crack here, not so much so it's done in a flash, but I think you may be starting at too low of a charge temp. In my experience with IR roasters, it's best to start with as much energy as possible since the energy input is so gentle. I also make few if any energy setting adjustments. Most my adjustments are to airflow, and I feel that you moving the airflow through the drum at that stage is slowing your roast down. In the Diedrichs, the exhaust is in the rear of the drum, which means that the airflow pulls energy away from the charge which is being promoted to the front of the drum by the baffling. I generally kept the air through the cooling bin for the first part of the roast, then moved to 50/50 around 300 degrees when the color had moved to yellow/golden. I would also move the air back through the bin right before 1st C, so as too kinda give it a boost heading into the crack, but only for a bit, being sure to change it then to full drum to clear chaff for about 30 seconds, then finish at 50/50 depending on how the roast was going. With a 9:45 1st C, I'd want to see that roast be more in the 12 minute range to get the most brightness out of it.

Hope this helps, keep us posted.

#5 stay tuned for next round results

Ok, thanks so much for the insight. I'll roast another batch with your suggested changes. The airflow strategy is a new technique for me.

#6 Confirming higher charge temps

I've got both an IR-1 and now an IR-2.5 for a new project. I started with low charge temps on the IR-1 and have slowly bumped them up over time after reading many discussions of the 1st phase of the roast. When I got the 2.5 I just went ahead and started testing profiles with higher charge temps.

For a 1000 gram batch I charge at around 375 and I bump that up to 400 degrees when using a 2400 gram batch. I get a temperature turnaround at around 1:15.

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