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I would bet, with about a 90% chance of success, that when you ask a coffee roaster what their favorite coffee-growing country is, they’ll tell you either Ethiopia or Kenya. Luckily for you, coffee roaster, both are back in town.

In addition to this week’s release of an Organic Crown Jewel from Homacho Waeno in Ethiopia, we also got our hands on this stellar, certified organic Kenyan coffee from Muiri Estate.

It’s super rare to find organic coffees in Kenya, so this rare gem not only checks the box of being delicious, but also of being certified. Muiri Estate is in Kiambu, just north of Nairobi but a little south of the more frequently seen specialty producing regions of Nyeri, Kirinyaga, and Embu.

We were super happy to taste this timely Kenya arrival, and pleased as punch to find it well balanced, notes of orange juice and cranberry in the acidity, but without being overwhelming. Cuppers noticed black tea and dried date, as well as plum, white grape, and a hint of tomato. A clean and lovely delivery from Kenya, and one you’re sure to enjoy (even if it doesn’t make your top two coffee origins).

green

Graded as an AB, this coffee mostly falls in the 16 and 17 screens with pretty minimal distribution outside 15-18, quite similar to a Central American European Prep. The moisture is low, and the density is very high, characteristics of coffees grown in Kenya, albeit surprising to find such high density numbers at the slightly lower elevation of Kiambu (compared to Nyeri, e.g.).

Coffees cultivated at Muiri include the classics: SLs 28 and 34 are specialty selections were made by Scott Agricultural Laboratories in the 1930s. Scott Labs (SL) were established in a building formerly used as a sanatorium and hospital in the town of Kikuyu in Kiambu county, a stop along the Mombasa railway just northwest of Nairobi. SL28 was selected and released as early as 1931 from a bronze-tip Tanganyika (now Tanzania) drought-resistant variety, and was lower yielding and less resistant to disease than intended, but it did achieve a high sensory quality, which explains its ongoing popularity. SL34 is a Kenyan selection, from a single tree observed in Kabete in a field labelled as French Mission, presumably Bourbon trees. It’s a bit more productive than SL28 and better suited for planting in lower elevations. Like SL28, its new growth is also bronze-tipped. World Coffee Research indicates that genetic testing of both SL14 and SL34 suggests they are closer to Typica than Bourbon, meaning the French Mission selection story might be incorrect. K7 is also a Scott Lab selection (though it does not bear the SL moniker) made in 1936 from a Bourbon tree resistant to leaf rust, a characteristic the cultivar no longer exhibits.

Additionally in play is Ruiru 11, a complicated cocktail of a cultivar. Although it’s considered an F1 hybrid, it is quite a bit more complicated than a cross of two traditional varieties. Ruiru 11’s manually pollinated parents are themselves complex hybrids, using varieties including SL28, SL34, Sudan Rume, a few Bourbon selections, and a number of Catimors with the intention of achieving a blend of CBD (Coffee Berry Disease) resistance, compact stature, high yields, and cup quality. It is named for the research station where it was bred.

taste

ikawa

We’ve updated our V2 Ikawa Pro machines with the latest Firmware version (24) and run on “closed loop” setting. Our roasters underwent full service in October of 2018 which included replacement heating elements and an updated PT 1000 temperature sensor.


I’d sample roasted this coffee a handful of times, the old analog way, prior to tossing 50g into the Ikawa Pro, and felt pretty confident in using a lighter profile with low rate of rise at the end of the roast would produce good results. My early manual roasts suffered from overdevelopment after first crack, as the coffee seems to take on color quickly during this roast stage. Instead, the lighter, quicker, high airflow profile on the Ikawa produced a coffee that yielded black tea, honey, cranberry, and citrus notes with a solid plummy flavor as the dominant expression. Ikawa roasts can be tricky, and sometimes don’t always bring out the best in a coffee if the profile isn’t dialed in, but in the case of this batch from Muiri, at least, the Ikawa produced perhaps one of the best roasts we tasted and offering a lot of insight into the potential the coffee has for excellence.

You can download the profile to your Ikawa Pro app here:

Roast 1: RC ckornman 6m afmod dec2018v3

probatino

Another Crown Jewel, another African coffee! ‘Tis the season, and for most roasters I know, that season isn’t Christmas – although it can feel like it! This time our organic Crown Jewel offering is a deliciously sweet and fruit forward Kenyan AB coffee from the Muiri Estate in Kiambu. It’s an extra special present under the tree in that it is a certified organic offering from Kenya – one of very, very few that you can find from this origin this year. The coffee hovers around a medium to large screen size, as you might expect. Delving straight in and being aware that although the coffee was lower on the moisture side but still dense, I knew that I had to walk the line of giving the coffee enough heat to convert all those sugars weighing it down into a sweet and flavorful cup.

I started this coffee on a medium heat. The density of this coffee isn’t related to a high moisture content, nothing like that to battle with at this stage. The gas at 2.5 allowed the coffee to dry evenly, but it still took longer to color than I was expecting. That being said, roast kept moving along at a steady pace and, keeping an eye on the heat delta, I noticed a respectable RoR and so decided to leave well enough alone. I wanted to ensure this wonderfully dense coffee didn’t stall, and to give it enough heat and time to allow all of those sugars to make their way into the cup. The smells coming off of the trier were both encouraging and enticing!

Christmas wouldn’t be Christmas without a little bickering or drama (at least, not when we were kids!), and so much like the season itself, just when everything seemed to be perfectly rosy we hit a snag. Although the coffee was taking on color after first crack, it seemed to be doing so awfully quickly. I began to worry –  the color kept coming, but the RoR was crashing. I had misjudged just how much heat I would need to carry this coffee through first crack and into a respectable post-crack development phase. Did I panic? I did not (Narrator: she panicked). So, quietly… perturbed, I did something I don’t usually like to do at all, turned up the gas to see whether I could preserve what had been a perfectly easy-going roast up until this point. I was really worried that a crashing RoR followed by a step upturn in the same, would lead to roast notes and squash the acidity that Kenyan coffees are so well known for. Luckily the cup didn’t disappoint, and I was relieved to find that my unorthodox heat application didn’t leave its mark and ruin the coffee at all.

Before we delve into what we found in the cup, I want to mention that if I were to roast this coffee again on the Probatino, I would more than likely make sure the heat was higher going into first crack, and then come off of the heat almost immediately after it started to go to far into a rolling first crack. In this way, I would be able to prevent the coffee from stalling, and allow for the fact that I know that it will take on color very quickly and achieve the results I wanted without the minor heart attack I had the first time. In general, I would suggest a more thoughtful step-down approach, with the knowledge that the beans need that energy to carry along for the initial ride into PCD.

And on the cupping table we were greeted by a staggeringly sweet cup full of notes of concord grape, mimicking a grape jelly vibe. Black cherry, peach, and plum with a hint of smooth vanilla and black tea. The coffee had the intense sweetness of maple syrup, caramel, nougat, and roasted walnut. What was surprising, unique, and delightful was the mild strawberry and starfruit-like acidity which made the coffee extra special. And which brew method would I recommend this Organic Crown Jewel for? All! Well, I mean, it is Christmas after all!

quest m3s

This was a perfect coffee to roast on the very day I roasted it. To give some context, I roasted this coffee on the hottest June 10th on record here in Oakland, California. It was 98F outside. But my trope for this coffee is that it wanted MORE HEAT. So don’t be shy with this one, at least in the beginning.

My charge temperature for this coffee was 393F, a pretty standard starting temperature for the Quest M3s as far as my roasts have gone. This coffee soaked up a lot of heat, and turning point was at about 224F. For this roast, I had the fan as low as it could go, and the back of the roaster open to stymie airflow until 1:15, when I closed the back and engaged the fan to about ‘3’ on the dial. As soon as the drying phase was over at 3:20 (a bit later than normal!), I turned the fan to full power. This had a drastic effect on the roast, and I spent the majority of my time (45.8%) in the Maillard phase. Crack was at 7:06/387F, and continued in a leisurely fashion for the next 1:15, for a post-crack development of about 14.5%. I did reduce heat to 7.5A just after first crack. This coffee didn’t lose a lot of momentum post-crack, so be careful about heat application later in the roast.

Results on the cupping table were very pleasant indeed. Vanilla, black cherry, cardamom, and grapefruit were all dancing in the cup. This is an absolutely phenomenal coffee to have as a filter drip or (dare I say?) a flash-brewed iced coffee. A fun coffee to roast, and even better to drink. Just remember to hit it with plenty of heat, and back off toward the end!

brew

“Pick two numbers,” I asked our barista Ruthie Knudsten. Ruthie joined The Crown team to help launch our Tasting Room back in January of this year. “9 and 10,” she responded.

I took two Chemexes (chemi?) and adjusted one parameter: grind size. I chose our trusty trade-show brew profile – 40g of coffee, 640g of water and adjusted the grind size on the EK43 to 9 and 10. It resulted in two pretty different brews, both great. Dialing in coffee often requires some pretty great guess work. While I wouldn’t recommend simply picking two numbers out of a hat, it’s not a bad place to start. And with a coffee like this, you cannot go wrong.

The finer grind yielded a tart coffee with some floral notes, while the coarser grind highlighted stone fruits and sugar browning flavors.

Origin Information

Grower
Muiri Estate
Variety
SL28, SL34, K7, and Ruiru 11
Region
Kiambu County, Kenya
Harvest
October-December | June-August
Altitude
1537-1550 meters
Soil
Volcanic loam
Process
Fully washed and dried in raised beds
Certifications
Organic

Background Details

KENYA ORGANIC KIAMBU MUIRI ESTATE AB GRAINPRO is sourced from the Muiri Estate located in Kiambu County, Kenya. Muiri Estate has over 443 acres of land with 216 in use for coffee cultivation intercropped with over 200 species of trees totaling more than 90,000, which includes grevillea and eucalyptus trees. Additional land has been set aside and shared with 1,000 local families to cultivate beans. The estate has its own wet-mill where cherry selection, depulping, fermentation, washing, and drying are meticulously executed. When coffee is milled for export, the green beans are sorted by screen size and graded according to size and shape. The beans from the 15/16 screen are labeled AB.