How Kona Coffee Is Made: Seedling to Roasting
Ever wonder what coffee looks like as it grows? We often discuss the roast profile, growing locations, tasting notes, etc., but rarely do we get a true window into each step of the growing process. The process of making Kona Coffee follows six main steps - Seedling & Grafting, Growing Cycle, Harvesting, Fermentation, Drying, and finally Roasting. Follow along as we detail the path of the world famous Kona Coffee from coffee seed to steaming mug.
Where does it start?
Kona Coffee grows on the western slopes of the Hualalai Volcano located on the west side of the Big Island of Hawaii. This location is ideal for growing great coffee due to its rich volcanic soil and very unique micro climate that provides consistent morning sun and afternoon rain throughout the year. Morning sun evaporates ocean water and trade winds push these newly formed clouds towards the Hualalai Volcano slope. Eventually these clouds get big enough to condense into afternoon moisture, creating the prefect combination of sun and rain for growing coffee.
This amazing micro climate also allows most Kona Coffee Farmers the ability to forgo the need for any formal irrigation of their trees. The consistent afternoon rain is usually enough to keep the trees watered and healthy throughout the year.
Seedling & Grafting
Kona Coffee starts its life as a green coffee seed. The seed varietal responsible for the world famous Kona Coffee is named Kona Typica. The Kona Typica varietal is well known for its amazingly smooth, non-bitter, and floral flavor profile. Its roots stock however, can be prone to disease and is often not strong enough to allow the tree to grow to its full potential.
To create a stronger coffee tree, it is a common practice for Kona farmer's to graft a Kona Typica seedling onto the root stock of a more robust coffee varietal. Donor root stocks can vary by farmer preference but one of the more popular choices for the Kona region is the liberica varietal. This varietal provides the coffee tree with the toughness needed to weather the many environmental challenges that might affect its growth and yield.
The grafting process involves cutting the Kona Typica seedling at its stem close to the soil and attaching it to the stem of the stronger root stock. Typically a simple clip or tie is used to bind the two stems together. Over time the two stems will merge into one creating a hearty tree that will only yield Kona Typica coffee beans.
Growing Cycle - Blossom to Red Cherry
Once the new seedlings are planted it takes about three to four years before they produce a significant yield of coffee. The growing cycle begins with sweet, pungent coffee blossoms that are locally referred to as “Kona Snow”. These blossoms eventually turn into a green coffee cherry that will take several months to ripen. The phrase “coffee cherry” originates from how similar the ripe coffee husk looks when compared with the popular red cherry fruit.
Kona Coffee tends to ripen in fall to early winter. This ripening window however can change dramatically based on elevation. The slope of the Hualalai volcano is relatively steep and has large temperature variations based on how low or high the farm is located. The higher elevation farms have an average annual temperature that is lower when compared with the lower elevation farms. The lower daily temperature results in the coffee cherries ripening later in the season as well creating a much more drawn out harvest season.
Harvest - Hand Picked
One big challenge with harvesting Kona Coffee is that the cherries do not ripen all at once. Since Kona Coffee is hand picked, the trees can be harvested many times throughout the long several-month harvest season. The coffee picker will select only the bright red cherries and leave the others to ripen for the next pass. Although hand picking is very labor intensive (and therefore expensive) it ensures only the best cherries are harvested. Also, by allowing the unripened fruit to stay on the tree until ready, the yields from each tree during a season is maximized.
The alternative is machine harvesting. This is not practiced on the Big Island due to the rough terrain and desire to maximize the yields of each tree. Machine harvesting is not selective and will remove most cherries from the coffee tree, ripe or green. Since coffee does not ripen uniformly the farmer must decide on the best time for this single pass to maximize their yield of red cherries. The mixed green and red fruit is then sorted post harvest. Farmers must weigh the efficiency of machine harvesting versus the lower yield of not allowing all the fruit to ripen. Another item that must be considered when mechanically harvesting is the potential flavor impact of less ripe fruit making its way into the finished product.
Post Harvest - Husk and Pulp Removal
Once the harvested coffee cherries are removed from the tree and they are immediately placed in tanks full of water to soak. Once submerged the coffee cherries begin to ferment. Typically left overnight, the fermentation process loosens the husk and fruit pulp layers of the coffee cherry making it much easier to physically extract the coffee bean. The fermented cherries are then sent through a mechanical scrubber that removes the husk and fruit pulp from the beans.
The method of soaking the coffee cherries immediately after harvest to allow fermentation to help remove the husk and pulp is referred to as a “washed” coffee process. The washed coffee process is the most popular processing method however, farmers often experiment with different processing methods in an attempt to influence tasting notes of the final cup in a positive way. An alternate method is to allow the just picked coffee cherries to dry in the sun with the husk still in place. This typically allows for a greater level of fermentation that will present in the cup as very bright and fruit forward.
A typical coffee cherry will contain two coffee beans. A rare anomaly to this is considered a “peaberry” where the cherry only contains one smaller, round coffee bean. This tends to occur in only 5% of the coffee harvested annually.
Drying In The Sun
The newly exposed green coffee beans are placed in the sun to dry. To ensure even drying the green Kona Coffee must be “raked” many times throughout the process. To protect the green coffee quality and prevent mold, most Kona Coffee is dried to a 12% moisture target. In this dried form and protected from the elements, green coffee beans may be stored for months before roasting with little to no impact on quality.
Depending on the farm, some locations are just too wet to completely dry the green coffee to the desired moisture level. In these scenarios farmers will often use propane fueled dryers in combination with, or as an alternative to, sun drying.
Roasting
Green Kona Coffee is most commonly roasted using a method of applying indirect heat in a rotating drum placed over top of a flame element. As the drum rotates, the heat from the flame transfers through the metal housing via conduction. This is currently the method favored by professionals as it allows very precise temperature controls throughout the roasting process.
A less common method but popular with home roasters is to use hot air. Similar to a popcorn maker, hot air is pushed up through the green coffee beans achieving the desired roast level via convection. This method results in even and uniform heating as the hot air passes through the bed of green coffee beans. One drawback however, is that this method tends to roast the beans very quickly making it a challenge to make adjustments during the process.
Roasters often create secret roasting recipes that they refer to as roast profiles. These recipes dictate the time and temperature at predetermined milestones during roasting. By changing the length of time needed to achieve a specific temperature set point, the roaster can often create a unique flavor experience related to the roast profile they created.
Fresh Roasted Coffee
During roasting the coffee beans will begin to release carbon dioxide. The beans must be allowed to rest for a couple days to a week before brewing to allow most of the carbon dioxide to dissipate. If brewed too soon the carbon dioxide molecules can interfere with the water extraction leading to a weak and under-extracted cup.
This slow carbon dioxide release is why many coffee bags have a one-way valve to help prevent pressure build up as the beans off-gas. A favorable result of this gas release however, allows coffee connoisseurs to determine just how fresh their coffee might be. Carbon dioxide is responsible for the “coffee bloom” or bubbles that form during brewing that many coffee enthusiast look for. Most of the carbon dioxide gas will dissipate and stop generating bubbles at around 1-2 months after roasting.
Washed Kona Coffee
Those are the six steps to how a typical washed Kona Coffee is made. Farmers and roasters often experiment with different variations of these steps in a never-ending attempt to provide the best coffee possible. The next time you enjoy 100% Kona Coffee we hope you have a new appreciation for just how much effort goes into that amazing cup.