Since we just released the fantastic Burundi Cumba, and we have more great Central African coffees on the way, now is a great time to talk about Potato Taste Defect (PTD). PTD is a non-toxic defect that commonly occurs in coffees from Rwanda, Uganda, Democratic Republic of Congo, and Burundi, and as the name suggests, the defect causes a distinctive raw potato aroma and flavor.
Because there are no discernable visual indicators of affected coffee seeds, it is impossible to detect and remove PTD affected seeds prior to, or after the roast. Average PTD occurrence rates are relatively low (roughly one affected coffee seed per 3-4lbs) and there is no risk of flavor or aroma transfer when the coffee is in whole-bean form, so if a PTD coffee seed is present, the defect is isolated to that single seed.
The best game-plan when brewing coffees from this region is to understand that PTD is likely, and mitigate the risk of it affecting a cup or batch brew of coffee. As always, grind fresh for each brew. If you detect the distinctive raw potato smell in the ground coffee, discard that batch, purge your grinder, and grind another dose. Coffees from this region are very special in their quality, character, and importance to each country’s economy. PTD is an inevitability with these coffees, but it is no reason to avoid enjoying all these coffees have to offer.