As I type this I am roasting up a batch of Kenyan coffee for home use. I just got done drinking, over the last few days, a batch of coffee from Los Naranjos en El Salvador, the farm of my friends, the Flores family. Four days straight of that same coffee (I don't think I had a single shop espresso or other coffee this week... amazing!), makes me crave something very, very different. So I dug through my bins of coffee and found a half a pound of coffee that Willem Boot let me have last time I was in California. It's a
free-trade fair-trade certified coffee, a "double A" (for what it's worth), and the designation is Gichathainike. I drank this before, in Seattle and California, and it's classic Kenya: bold, super bright, and snappy.
The problem with roasting this kind of coffee on my little Gene Cafe, however, is it really calls for high initial heat. This coffee, like most top-grade Kenyas, is grown at super high elevation. High elevation, even at the equator, leads to exceptionally cold nights, and the cold nights lead to denser, more compact beans. This is part of what gives Ethiopian and Kenyan coffees their distinct acidity... they are some of the highest-grown coffees in the world. Combine super-high altitude with the sheer screen-size bigness of these AA beans, and that's a lot of cell structure in one bean.
You kind of have to hit beans like this with a baseball bat of heat right off the bat. Just blow torch them. In a conventional drum roaster, the idea would be to increase your drop temperature 25 or 50 degrees, making sure you are at 100% airflow right off the bat to avoid scorching. You still want a nice slow roast development time leading into and after first crack. But you want to roast with high initial heat so you can get to that first crack sometime before the cows come home. But in a little electro-gizm like the Gene Café, you have to take the "drum" away from the heat source, open it up, and pour in the beans carefully. During this time the temperature is rapidly dropping.
So I just did my best on this Kenya (I pulled them and set them beneath the cooling fan about a paragraph ago)... crank the heat as high as possible, dump the beans in fast, and whisper coaxing words to them as they roast.
I just popped one in my mouth... I can taste that crisp acidity. I think this will be a good one. But I will have to wait until morning to find out.
I've noticed through the years that Kenyan coffees tend to include an abnormally high number of "shell" beans, even in premium and specialty grade coffees that are otherwise free of defects. This is a minor defect and totally forgiveable; but still I wonder why this is. I can't believe I've never asked around for an answer on why this is! I'm curious if there's something about the varietals there or (less likely?) the processing, that creates this. The simplest explanation I can come up with is that sorters there do not consider this a defect and so they simply leave in the "shell" beans they see. With luck I will be in Kenya in November and hopefully I can find out first-hand, but if anyone reading this knows the reason for this... please share! (shell bean image from coffeeterms.com)