Picking and Processing: Key Steps to a Fine Cup

Most coffee trees have the maddening habit of maturing their fruit unevenly. If harvesters pick all the coffee cherries on a farm at once, some berries will be red-ripe, some green and under ripe, and some raisiny and overly ripe. Underripe beans can produce green or grassy flavors in the brew; overripe beans can add a fermented or moldy taste. Neither type belongs in a fine cup.

That's why the most conscientious coffee producers pick their farms multiple times, so they are always harvesting fruit at peak maturity. That's expensive, of course, but it's the only way to avoid off flavors. Pastry chefs know that you can't make a good peach pie with under-ripe or over-ripe peaches, and the same argument explains why it's critical to pick coffee at the right time. Machines do a decent job of shaking ripe fruit off of coffee trees, but they aren't as discriminating as humans. Consequently, the finest coffees are always hand picked.

After harvesting, the coffee cherries must be processed to remove the pulpy fruit outside and retrieve the two sought-after seeds inside. Think of the coffee cherry as resembling a grape, with moist, sticky fruit surrounding the hard seeds (although coffee seeds—the beans—are much larger than grape seeds). Different producers use different processing protocols, which can greatly affect flavor. But for ease of discussion, let's divide them into dry, washed and semi-washed methods.

In dry processing, the whole cherries are sun dried before the outer pulp is removed. The just-picked cherries are arrayed on trays outdoors, left to bake in the sun for 10 days to three weeks, and raked often so they dry evenly. Then the dried pulp is removed mechanically. This type of coffee is also known as unwashed or natural. If you want to taste a dry-processed coffee, buy Brazil Santos, Ethiopian Harrar or Yemen beans.

For washed coffee, an alternative method, the just-harvested cherries are transported to a processor, who skins the fruit mechanically to expose the sweet, sticky pulp. The beans are left to ferment in tanks for 12 to 18 hours, a step that helps to soften the pulp, then washed and dried. This method is the most common in the world of fine coffee.

For semi-washed beans, a variation of the washed technique, the pulp is removed mechanically, omitting the fermentation step. This method saves water but doesn't allow the processor to enhance flavor through fermentation.

Each process, done right, contributes desirable characteristics. Dry-processed coffees tend to be fruitier, rounder, fuller bodied and more complex because the bean is in contact with the pulp longer. Washed coffees retain the most acidity, while semi-washed coffees are relatively richer and earthier flavor. Done by a quality processor with quality beans, each technique has its advantages.

Finally, before coffee beans go to the roaster, they are sorted by size, density and color and then graded. Color sorting eliminates defective beans. The finest beans may be hand sorted two or three times.

Recipe links:
Apple Jack Ribs Smoked over Coffee Beans with Coffee Barbeque Sauce