Why Select Defective Coffee Beans? What Flavors Do They Bring to Coffee?

Coffee is an agricultural product, so raw beans naturally come with defects of one kind or another. Ask any producer or roaster and they'll tell you the same. Fortunately, these defects can be spotted visually, so as long as a roaster has enough experience to notice beans with undesirable characteristics and pull them out before roasting, the problem isn't hard to manage.

Multiple Center Cracks

As the name suggests, these beans have spoiled during processing through over-fermentation. They look somewhat rotten and take on a tobacco-like color. Just one or two of them are enough to ruin an entire cup, since they carry a strong rotten smell and an unpleasant sour taste. Even beans that are only slightly over-fermented already show a distinct onion flavor.

Diseased Beans

Common coffee tree diseases include coffee berry disease and leaf rust. Fruit from diseased trees is mostly underdeveloped and dark in color. If cherries aren't carefully picked at harvest, or if machines are used to strip the trees indiscriminately, diseased cherries and green beans end up mixed in with healthy coffee, which can spread the disease further.

The more you understand the various defects of green beans, the better you'll know what steps to take to solve, prevent, and avoid them. Analyzing green beans is one of many quality-control measures in the specialty coffee industry. The better the collaboration between producers and roasters, the lower the chance of these defects appearing. Understanding coffee growing regions - their environment, climate, and changes - matters just as much. Some regions may have just come through a drought, while another might have been hit by heavy rain. Some producing countries are especially vulnerable to coffee leaf rust or damage from the coffee berry borer. The point is this: the more current, complete, and rich your information as a roaster, the better your decisions will be when you buy green coffee.

At FrontStreet Coffee we normally sort out defective beans at least three times: once before roasting, once after roasting, and once before brewing.

FrontStreet Coffee Recommendation

Careful sorting is what keeps a cup clean, so for everyday brewing we reach for balanced medium roasts where flawed beans would show up immediately. FrontStreet Brazil Queen Estate is a good example: a Yellow Bourbon from Brazil, medium-roasted, with cream peanut, chocolate, toasted bread and sugarcane sweetness on a clear, gentle body. Prefer something softer still? FrontStreet 2013 Natural Typica, a medium roast, brings nuts, brown sugar, black tea and a hint of dried apricot. Both work well as pour-over, in a moka pot, or as espresso, and neither has anything to hide.