Roasting Naturals – Ethiopia

By Christopher Schooley

I recently had a discussion with a roaster who was having difficulty with a natural dry processed coffee from Ethiopia. He did not have much experience roasting DP coffees and had not really even considered how coffees processed in that style were different. He believed that the problems that he was found in the cup were the result of the beans not all being of a uniform size since he was not having similar problems with other coffees that he was roasting (which happened to all be washed coffees and thus of a more uniform bean size). So his response to his difficulties with this coffee was to separate the coffee by screen size in order to achieve uniformity. This did eliminate the “off” tastes that he was getting, but those “off” tastes could have been taken care of by adjusting the way that he was roasting, and what he ended up doing was changing the character of the coffee by separating out non-defective beans, beans that actually added to the overall quality of this coffee and in fact the Longberry bean shape of the Ethiopian heirloom varietal led to his separating almost 40% percent of this coffee out of what he planned to roast. I’ve personally done the DP Ethiopian green coffee sort and cupping experiment and my own results were that the more uniform selection had perhaps more balance, but lacked the sweetness and complexity that the coffee had as a whole (unseparated). Tom has done the experiment with a washed Ethiopia Yirg, here: http://www.sweetmarias.com/yirgacheffescreentest.html and had some insightful findings but ultimately reached the same conclusion.

Now as I said, this is someone fairly new to roasting and I’m not trying to simply point out a mistake but to use this opportunity to note one or two or more things:

1. Bean size indicates bean size, not quality.
2. A washed or Wet Process coffee goes through a level of separation that Dry Processed coffees don’t, but that doesn’t mean that a DP coffee is full of junk and defects just because the beans are different sizes.
3. Removing quakers from a coffee should be done after the roast, this cannot be achieved through a bean size separation.
4. The variation in bean size which is common in DP Ethiopian coffees does dictate that it is important to allow the coffee to move into a full and vigorous pop before reducing the gas rather than making an adjustment right when you hear the first signs of popping.
5. Your answers are in cupping and roasting, and then doing it again.
6. If you’re having a problem with a coffee, ask another roaster. One of the things that I’ve most enjoyed about Coffee Shrub are the comments from other roasters and the idea that people can share their experiences with a coffee, or their difficulties, and get some feedback, advice, and encouragement from others.

15 screen Ethiopia Maduro DP
15 screen Ethiopia Maduro DP

Everything that passes through a 15 Screen on Maduro , but because of the longeberry bean form, many things get through that would not on another coffee with the same bean length, The real issue is what the significance of bean size truly is … if the coffee cherry was ripe, processed and dried well, there is no reason for a smaller bean size to be of any less quality in the cup as a larger bean. In fact, there is a chance that smaller bean sizes are more dense seeds, and could be better in the cup

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