‘Tis the season for delicious coffees from tiny African countries—specifically, Rwanda and Burundi. We’re pretty excited about our offerings this year from both countries; which have some really complex flavors and intense sweetness. Unfortunately, once in a while we experience something sad and unpleasant in these coffees… dun dun dunnnnn... the “potato defect.” It is important to understand what this “defect” is, how to recognize it and what to do when you encounter it.
What is the “potato defect?”
The potato defect gets its name from the pungent, raw potato smell it gives off and an overpowering, unpleasant taste. It is caused by bacteria, which infects the fruits of the coffee, while on the tree, thought to happen after the Antestia bug, or coffee borer beetle has bitten the cherry. The fruit can become infected after any puncture of the skin of the cherry, but the beetle seems to be the most likely cause. The organic chemical that causes the potato like smell is 2-methoxy 3-isopropylpyrazine, which is apparently also found in ladybugs. While the coffee borer beetle is found in other parts of the world, its damage of this type seems to manifest mainly in east Africa. This bacteria in the cherry and the resulting potato smell is not harmful in any way, other than inducing great sadness while drinking an affected cup.
What should I do about it?
Fortunately, the potato defect is isolated in individual beans. If there is an affected bean in the batch you grind, it will be easily detectable by a quick sniff. If this happens, the best option is to dump the grounds and dose a new batch. As we mentioned, we’ve seen this problem less and less each year, so we don’t expect to have to toss too many batches—but this information is good to have if you do encounter potato. It’s extremely easy to make sure every cup is tasty, especially if you’re brewing by the cup. We strongly encourage folks who buy coffees from Rwanda and Burundi to NOT get all of the coffee ground at once, so that if you do encounter this defect, you don't ruin the whole bag of coffee! Plus-- grinding before each cup or batch does a lot for the overall deliciousness of the brew.
Well, shouldn’t Dogwood stop buying these coffees if they have this “defect?”
NO! Unfortunately, the defect is a very hard thing to detect visually. Really amazing, high scoring coffees can be affected with this defect, and because it doesn’t affect the whole crop, we see no reason to stop offering coffees from two entire countries. The people there certainly don’t want the potato defect to affect their coffees—they are well aware of it and good coffee producers go to great lengths to remove the risk of it appearing as much as possible. Density sorting, visual sorting for bug damage, and good initial cherry picking can lessen the risk. We have been buying these coffees for the past four seasons and each year the frequency of the defect has decreased. We can support the progress of eliminating this problem by continuing to buy delicious coffee from Rwanda and Burundi.
We just finished up our little lot of the Rwanda Kigeyo, but our current offering from Burundi, Civugiza, is now available! We've had success so far with this coffee and have found very few cups with potato. And, it's super delicious! Check it out here.