Dry processDry process coffee is a method for taking the fruit from the tree to an exportable green bean. The whole intact coffee cherry is dried in the sun... ...more seems simple, but creating a great-tasting dry processed coffee requires a lot of extra labor.
Dry process seems simple: Pick the fruit, lay it out in the sun until it turns from red to brown to near-black, and then hull off the thick, dried outer layer in one step to reveal the green bean. It is a method suited to arid regions, where the sun and heat can dry the seed inside the intact fruit skin.
It’s often referred to as “natural coffee” because of its simplicity, and because the fruit remains intact and undisturbed, a bit like drying grapes into raisins. Since it requires minimal investment, the dry process method is a default to create cheap commodity-grade coffee in areas that have the right climate capable of drying the fruit and seed.
But it’s a fail in humid or wet regions. If the drying isn’t progressing fast enough, the fruit degrades, rots or molds.
Dry-processing of coffee can also be wildly inconsistent. If you want a cleanly-fruited, sweet, intense cup, dry process (DP) takes more hand labor than the wet processWet-processing starts by removing the outer skin of the coffee cherry with a machine called a pulper, then fermenting the remaining fruit (with green bean inside) in water... ...more. Even the most careful pickers will take green unripe or semi-ripe coffee off the branch as they pick red, ripe cherryEither a flavor in the coffee, or referring to the fruit of the coffee tree, which somewhat resembles a red cherry.: Either a flavor in the coffee, or... ...more. If these are not removed in the first days of drying, the green turns to brown that is hard to distinguish from the ripe fruit.
Interestingly, there are arid zones where the coffee starts to dry while on the tree. Areas of BrazilBrazil is a coffee giant . As Frank Sinatra sang, "they grow an awful lot of coffee in Brazil".: Brazil is a coffee giant . As Frank Sinatra... ...more, in particular, have very distinct rainy and dry seasons, and in the dry times when coffee is harvested, the heat is intense enough to parch the coffee fruit while it is on the branch. These are called “pasas” in Latin American areas, raisins, and they have a leatheryAromas or flavors reminiscent of leather, a very rustic quality and not necessarily a defect.: This descriptor is somewhat reminiscent of the leather, and is sometimes distinguished as... ...more fruit texture. Cherry forgotten on a tree will also dry, sometimes fully to the stage where the seed is rock hard. These are often called “pods” and are considered a defectIn coffee, a defect refers to specific preparation problems with the green coffee, or a flavor problem found in the cupping process. Bad seeds in the green coffee... ...more when they appear in sorted, hulled, ready-to-export coffee.
For areas that don’t have intense heat and distinct seasons, the coffee is picked ripe, just as a wet-process coffee would be. The coffee is laid on raised drying beds that allow air to circulate around the fruit. The beds use metal screens or metal bands that support a nylon woven cloth (preferable). Sometimes locally woven grass mats are used.
As the cherry dries, the skin and attached pulp (exocarp, mesocarp) attach to the parchmentGreen coffee still in its outer shell, before dry-milling, is called Parchment coffee (pergamino). In the wet process, coffee is peeled, fermented, washed and then ready for drying... ...more layer (endocarp). The mucilageMucilage indicates the fruity layer of the coffee cherry, between the outer skin and the parchment layer that surrounds the seed. It readily clings to the inner parchment... ...more layer that is degraded by fermentationA key part of the wet process of coffee fruit is overnight fermentation, to break down the fruit (mucilage) layer that tenaciously clings to the coffee seed, so... ...more in the wet process is sandwiched in-between. The silverskinOn dried green bean coffee, the thin inner-parchment layer that clings to the bean and lines the crease on the flat side. Silverskin becomes chaff and falls off... ...more (chaffChaff is paper-like skin that comes off the coffee in the roasting process. Chaff from roasting is part of the innermost skin (the silverskin) of the coffee fruit... ...more when roasted) often stays attached to the bean.
In wet-process (WP) the fruit skin is peeled off by the pulper, and the remaining fruit is fermentedAs a defect flavor, a fruit quality in a coffee that is excessively ripe, toward rotten. Fermented flavor can be the result of poor wet-processing, over-ripe cherry, or... ...more and washed off. But in DP the coffee seed dries encased by the thicker layer of fruit skin. The active transference of water and ionic bonding with compounds in the fruit skin is a likely way that the fruitedIn some coffee taster’s lexicon, “fruity” means the coffee is tainted with fruit, and “fruited” means a coffee is graced by positive fruit notes. We don't exactly see... ...more notes of a DP coffee are infused into the drying seed.
The bulk of DP coffee in the world is commercial grade coffee, with dirty/earthy and mustyOff aroma and flavor that reminds one of a dank, moldy closet. This flavor can hint at a dangerous coffee mold and should not be consumed.: Off aroma... ...more flavors. Many farmers receive little for their DP coffee so it receives little care: The coffee is dried on tarps or directly on dirt. Coffee that falls to the ground or is re-wet while drying is recovered and sold to traders. It takes incredible intention and care to create a premium dry processed coffee.
All DP is milled the same: With a relatively crude purpose-designed huller machine, the thick dried fruit skin is removed with friction burrs. The skin can be fanned and cleaned to use as a tea (called QishrQishr is an infused tea beverage that you make using the dried coffee husks of the coffee fruit, a by-product of of the natural dry-process method. Now it... ...more in YemenYemen has a coffee culture like no other place, and perhaps some of what we enjoy in this cup is due to their old style of trade...: Technically,... ...more, Geshir in EthiopiaEthiopia is the birthplace of coffee: it is in the forests of the Kaffa region that coffee arabica grew wild. Coffee is "Bun" or "Buna" in Ethiopia, so... ...more).
Because DP skips all the steps in WP to remove defect beans (floating the wet parchment, the “criba” in the pulper, densityThe density of a coffee bean is often taken as a sign of quality, as a more dense bean will roast more with a better dynamic. The density... ...more grading in washing channel, etc.) all defect beans must be removed visually, or in the dry millA facility that accepts dried coffee cherry and mechanically separates the coffee bean from the dried fruit and parchment layer. The facility can be highly mechanized, as in... ...more. After the critical density table step, coffee is again hand-picked. Even the best DP coffee has a less-uniform look because of the silverskin still attached to many beans.
Natural coffees are perhaps the original method to process coffee. If the first coffee grown as a commercial crop, for trading, was in Yemen, the climate is well-suited to dry processingThe removal of the cherry and parchment from the coffee seed.: Coffee is either wet-processed (also called washed or wet-milled) or dry-processed (also called wild, natural or natural... ...more. The western parts of Ethiopia such as Harar are traditional dry-processing areas. Older coffee-growing areas of Brazil as well as newer ones (Cerrado) have distinct seasons ideally suited to dry process method. If a farm can dry coffee from ripe cherry to hard, dried pod in 20 days, it is probably well-suited to DP methods.
Generally speaking, we will cup but usually not buy naturals from areas that cannot dry the coffee in the proscribed amount of time. Naturals from Central America present a good example, although we are always open to new areas and enterprises that can do it right.
In recent years, many areas that do not traditionally produce dry-processed coffee have begun to do so for a varietyHibrido de Timor abbreviated HdT is the interspecies hybrid of C. Arabica and C. Canephora (Robusta) that was found in Timor Leste in the 1940s. It has been... ...more of reasons. The spread can be attributed to market demand, as many buyers find the fruityIn some coffee taster’s lexicon, “fruity” means the coffee is tainted with fruit, and “fruited” means a coffee is graced by positive fruit notes. We don't exactly see... ...more tastes of DP coffees easy to distinguish for themselves and their customers. The distinction of exactly what kind of fruity flavors are good and which are bad is an open question.
Certainly, there is a matter of personal preference, which is influenced by cultural preferences as well. The distinction between clean fruit notes, wineyA taste term to describe a wine-like flavor with a similar perceived acidity and fruit, and some level of acetic acid. It is found most commonly in East... ...more fruit and vinegarA defective flavor taint in coffee, resulting perhaps from poor processing, fermentation, sanitation.: Vinegar-like qualities are a defective flavor taint in coffee, resulting perhaps from poor processing, fermentation,... ...more seems universal, but on the cuppingCupping is a method of tasting coffee by steeping grounds in separate cups for discrete amounts of ground coffee, to reveal good flavors and defects to their fullest.... ...more table, there can be disagreements. One person’s “ferment” is another person’s “fruited”. Go figure. I find many new buyers or those from countries with a newer coffee culture are either quick to over-praise or over-punish these fruit notes.
One experience with naturals that is not so relative to personal taste is the stability of the coffee over time. DP coffees that are not fully rested, or were too-slow to dry will tend to fade. A marginal fruit note tasted in a fresh arrival of such a coffee might be pleasant in the present, but in several months it might fade. What remains might be flat woodyGenerally a taste defect from age; old green coffee, perhaps yellowing in color. This is due to the drying out of the coffee over time, and as the... ...more or earthyEarthy is a flavor term with some ambivalence, used positively in some cases, negatively in others.: Sumatra coffees can have a positive earthy flavor, sometimes described as "wet... ...more notes that few find attractive, unless you add sugar!
Beyond climate, a quality DP coffee requires tons of hand labor, for multiple iterations of picking. Many areas simply do not have the amount of labor available, or the labor is not affordable. In Brazil they must use only the dry mill machinery to clean the coffee of defects: Even selective hand-picking requires too much labor and would drive up the price of coffee to untenable levels.
But in this resurgence in the dry-process technique, some wonderful new coffees have come to light that have the consistency, uniformity and clean taste that rival wet-process coffees, but have complexThe co-presence of many aroma and flavor attributes, with multiple layers. A general impression of a coffee, similar to judgments such as "balanced" or "structured" ...more layered fruit flavors not found in their counterparts.
Just roasted some Panama DP from you and oh the smell! So much chaff, it took several passes to get to the finished bean! Thank you for this wonderful article!
Yes that one is quite an extreme coffee in terms of both the appearance and the amount of chaff too! Most dry process coffees have more chaff. But the Panama definitely had more that “normal!”