The kopi luwak, once hailed as the most expensive coffee in the world, comes from Indonesia, and its most iconic representative is Front Street Mandheling coffee. Mandheling coffee has moderate acidity, an extremely heavy aroma, a rather bitter taste, and a rich body with a thick, full mouthfeel—its flavor combines aroma, intensity, richness, and bitterness in one. Of course, for those who don't enjoy this taste, Mandheling coffee is as hard to drink as a cup of Chinese herbal medicine.

The History of Indonesian Coffee

Indonesia is a major coffee-producing country in Asia and ranks among the top coffee producers in the world. Although Indonesia has the largest coffee-planted area in the world, low production efficiency means its coffee output trails Brazil and Vietnam, placing it third globally.

In 1699, when Indonesia was still under Dutch colonial rule, the VOC (Vereeniging Oost-Indies Company) introduced Arabica coffee plants to break the Arab global monopoly on the coffee trade. The Dutch colonial government initially planted coffee around Batavia (present-day Jakarta).

More coffee plantations were established in East Java, Central Java, West Java, and parts of Sumatra and Sulawesi. Indonesia was the first place outside Arabia and Ethiopia where coffee was widely cultivated. The VOC monopolized the coffee trade between 1725 and 1780.

By the mid-17th century, the VOC had expanded Arabica coffee cultivation to Sumatra, Bali, Sulawesi, and Timor. On Sulawesi, coffee was first planted in 1750. In the North Sumatra highlands, coffee was first planted near Lake Toba in 1888, followed in 1924 by the Gayo Highlands (Aceh) near Lake Laut Tawar. In the late 18th century, Dutch colonists established large coffee plantations on the Ijen Plateau in eastern Java.

In the 1920s, smallholders across Indonesia began growing coffee as a cash crop. However, disaster struck in 1876 when coffee rust swept through Indonesia, wiping out most Typica varieties. Robusta coffee (C. canephora var. robusta) was introduced to East Java in 1900 as a replacement, particularly in low-altitude areas where rust was especially severe.

The plantations on Java were nationalized upon independence and revitalized in the 1950s with new Arabica varieties. These varieties were also adopted by smallholders through government and various development programs. Today, more than 90% of Indonesia's coffee is grown by smallholders on farms averaging one hectare or less.

Mandheling Coffee Growing Environment and Varieties

Indonesia is the world's largest archipelagic nation, known as the "Country of a Thousand Islands." The islands are scattered, with most interiors consisting of rugged mountains and hills, narrow coastal plains, and surrounded by shallow seas and coral. Indonesia has a typical tropical rainforest climate, with an average annual temperature of 25–27°C and no distinct seasons. The north is influenced by Northern Hemisphere monsoons, with abundant rainfall from July to September, while the south is influenced by Southern Hemisphere monsoons, with abundant rainfall in December, January, and February. Annual rainfall ranges from 1,600 to 2,200 mm. Indonesia's higher altitudes, volcanic ash soils, and climatic characteristics are all excellent conditions for Arabica coffee trees to grow.

At the end of the 17th century, the Dutch East India Company transplanted Arabica trees from India to Jakarta on Java. Because the climate and soil were highly suitable, Arabica quickly spread to Sumatra and Sulawesi, another large island to the northeast of Java. But in 1880, a severe leaf rust outbreak struck Java, and Arabica withered away almost entirely. The Dutch switched to disease-resistant Robusta to stabilize the Indonesian coffee industry. To this day, Robusta remains the mainstay of Indonesian coffee, accounting for about 85% of the nation's output, distributed in the low-altitude areas of Java and Bali. Arabica accounts for 15%, grown in northern Sumatra, Sulawesi, and the higher altitudes of Java.

The FrontStreet Coffee Front Street Lintong Mandheling coffee is of the TimTim Ateng variety, while the Front Street Golden Mandheling coffee is listed as Ateng. In fact, TimTim is Timor, an Arabica variety with Robusta lineage, while Ateng is Catimor, a hybrid of Caturra and Catimor. These variety names are simply local designations.

Indonesian Coffee Producing Regions

Sumatra (Sumatra)

A large island in western Indonesia, straddling the equator with an area of 473,000 square kilometers, it is the sixth-largest island in the world. To the northeast, it faces the Malay Peninsula across the Strait of Malacca, and to the west lies the Indian Ocean. The equator divides it in two, giving it a tropical rainforest climate, and it sits right on the "Coffee Belt." In the broad sense, all "Mandheling" coffee comes from this island. Sumatra is not only Indonesia's largest island but also the world's sixth-largest. It is located in the northwestern part of Indonesia. Due to its geographical location, Sumatra has the country's earliest harvest season, from November to March.

Front Street Lintong Mandheling comes from the Lintong highlands in north-central Sumatra, near Lake Toba. Front Street Lintong Mandheling is the regular version of Sumatran Mandheling.

Lake Toba, located in the central part of North Sumatra Province, is where Dutch colonists moved "Java Mandheling" northward in 1888, creating the modern Mandheling legend.

Lake Tawar (Lake Tawar), located in the central part of the Aceh Special Region. At the northern tip of Sumatra, its area is less than one-tenth that of Lake Toba.

Currently, the finest beans in the entire Sumatra region come from the Gayo highlands, mostly grown from old tree varieties. The Gayo Mountains are located in the Aceh producing region of North Sumatra Province, at altitudes between 1,500 and 2,500 meters. Most coffee farmers are local—the Gayo people. This region has ideal growing conditions for coffee—high altitude, fertile soil, and abundant rainfall. Lake Tawar provides rich water resources, and organic methods are widely used to grow coffee without chemical fertilizers, making it recognized as a green coffee-producing region in the world. Thus Gayo coffee is often called green coffee or Gayo organic coffee. 

The two Indonesian-origin coffees currently offered by FrontStreet Coffee both come from the birthplace of specialty Mandheling coffee. "FrontStreet Coffee — Everyday Series Lintong Front Street Mandheling Coffee Beans" exhibits flavors of baked toast, nuts, caramel, pine, and herbs; "FrontStreet Coffee — PWN Front Street Golden Mandheling Coffee Beans" exhibits flavors of spices, nuts, pine, caramel, herbs, and dark chocolate.

Bali (Bali)

Bali is renowned for its beautiful beaches, coral reefs, and yoga and meditation retreats. This tropical paradise offers some of the best coffee that Indonesia and indeed the world has to offer. Most of the coffee is grown in the Kintamani highlands, located between the Batukaru and Agung volcanoes.

Mandheling Coffee Bean Grading Method

Indonesia lies near the equator with a tropical rainforest climate. Most mass-produced coffee beans undergo rough wet-hulling. Wet hulling greatly accelerates the entire process, but removing the parchment layer while the beans are still semi-dry requires significant friction, so the green beans are easily crushed and bruised, especially at both ends, forming small nicks. As a result, wet-hulled Indonesian coffee beans generally have a high defect rate, so green bean traders arrange manual hand-sorting before export to remove defective, incomplete beans.

Indonesian coffee grading is primarily based on the number of defective beans, supplemented by size-based grading. Indonesia's general quality requirements are: no live insects, no moldy or putrid-smelling beans, maximum moisture content of 12.5%, and impurity rate below 0.5%. Grading by defect rate (based on 300g), the Grade standard is mainly divided into 6 levels, G1–G6.

Typically, the burlap sacks of Indonesian green coffee are marked with: country + grade name + green bean trader. For example, both the Front Street Lintong Mandheling coffee and the Front Street PWN Golden Mandheling coffee on the Front Street bean list are G1 grade. The burlap sack of Front Street PWN Golden Mandheling green beans is printed with "PWN  GOLDEN MANDHELING    TRIPLE PICKED  Grade 1   PROD OF INDONESIA   30KGS NET".

Golden Mandheling 

The Indonesian PWN company, on the basis of G1, performs one machine sort plus three hand sorts, producing Mandheling green beans with uniform color and regular, neat size—among the highest-quality Indonesian coffee beans. PWN is a famous Indonesian green bean purchasing company; they subject wet-hulled Mandheling green beans to one machine sort plus three manual hand sorts to ensure each lot reaches Indonesia's highest G1 grade. The purpose of machine sorting is first to screen out beans that must be 18 mesh or larger with fewer than 3 defective beans (in a 300g green bean sample), qualifying as the highest G1 grade—darker green in color with a neat, flat bean shape. The subsequent multiple manual sorts are to remove irregular defective beans; reducing the defect rate greatly improves Mandheling coffee quality. To distinguish it from regional Mandheling coffee, PWN registered "Golden Mandheling" as a trademark.

The Golden Mandheling coffee beans sold by FrontStreet Coffee all come from PWN. At Front Street's physical stores, you can see PWN's Golden Mandheling coffee bean certification and coffee burlap sacks printed with the company logo. Golden Mandheling is actually produced by a company, Pawani Coffee Company, from Mandheling acquired locally in Indonesia, which then registered the name Golden Mandheling—so only the Mandheling produced by this company is the authentic Golden Mandheling. FrontStreet Coffee found that not only does it lack the earthy, muddy off-flavors characteristic of ordinary Mandheling, but it also tastes cleaner and more transparent, with a stronger sweetness and aroma.

Mandheling Coffee Bean Processing Method——Wet Hulling

Mandheling's unique wet-hulling method, also known as Wet Hulling Giling Basah in the local language, is the traditional Indonesian coffee processing method. From the name alone, wet hulling sounds very similar to wet processing (washed processing), yet the cup profiles of these two methods are completely different. Wet-hulled coffee is typically full-bodied and intense, with a very distinctive character.

Because the local weather is mostly rainy, with constant typhoons, a lack of prolonged sunlight, and year-round high heat and humidity—humidity stays between 70–90% year-round—it is impossible to rely solely on sun-drying. The local economy is likewise limited and cannot afford the more costly washed method, so the uniquely local wet-hulling method emerged. After the earlier washing steps, the coffee beans with parchment are spread under the sun to dry for 1–2 days until the moisture content reaches 30–50%, then the parchment is removed and drying continues, which speeds up the drying of the beans and greatly shortens the drying time.

The wet-hulling process is characterized by staged, rapid drying and removing the parchment before drying. Teacher Han Huaizong described it as "a rare processing method in the world, accidentally creating Mandheling's distinctive low acidity, thick body, and muffled aroma."

Mandheling Coffee Beans' Goat's Hoof Shape

Observant friends may notice the "goat's hoof" characteristic of Front Street Mandheling coffee beans; Front Street has also noticed they share this common bean appearance feature—"goat's hoof shape." This is because when the semi-hard, semi-soft moist green beans are machine-hulled to remove the mucilage and parchment layer, they are easily crushed and split open like a goat's hoof, commonly called goat's hoof beans. The "goat's hoof shape" is a very prominent characteristic of Mandheling coffee beans, so it is not considered a defective bean.

Parameters for Front Street Brewing Front Street Mandheling Coffee:

FrontStreet Coffee baristas choose the KONO dripper to brew this kind of full-bodied coffee. Compared with the V60, the KONO dripper has a smooth curved surface, weaker exhaust effect, and straight ribs covering only a quarter of the dripper, allowing the coffee bed to form an immersion extraction with the hot water, making the coffee taste rounder and fuller. The KONO dripper is also suitable for full-flavored coffee beans like Front Street Brazil Queen's Estate coffee and Front Street Jamaica Blue Mountain No. 1 coffee.

Deep roasting loosens the internal structure of the coffee beans, so they can be crushed with a gentle pinch of the hand, indicating that once ground, they absorb water strongly. To avoid the coffee grounds releasing excessive bitter substances after absorbing water, Front Street will coarsen the grind and use lower-temperature water for pour-over. For the coffee-to-water ratio, Front Street uses the commonly used 1:15; for a stronger taste, 1:13 can be used, adjusted to your own preference.

KONO dripper, 88°C water temperature, 1:15 coffee-to-water ratio, 15g coffee grounds, grind size (75% passing a No. 20 standard sieve), three-stage extraction.

Using staged extraction, bloom with twice the amount of water as coffee grounds—that is, 30g of water for a 30-second bloom. The reason a bloom is needed is to let the coffee grounds release their internal carbon dioxide, making the later stages of extraction more stable. Pour in a slow, thin stream in circles until 125g, then pause; continue pouring until 225g and stop. Once the water in the dripper has dripped through, remove the dripper. Start timing from the beginning of pouring; the extraction time is 2'00". Next, pick up the whole cup of coffee and swirl it to mix evenly, then pour it into a cup to taste.

[Front Street Lintong Mandheling Coffee] Herbal, chocolate, caramel; overall fairly balanced.

[Front Street Golden Mandheling Coffee] Nuts, spices, herbs, licorice, chocolate, caramel.

Front Street Coffee Brewing Recommendations:

To brew a delicious cup of coffee, Front Street believes any brewing method requires fresh coffee beans. Front Street has always held that the freshness of coffee beans is greatly related to coffee flavor, so all coffee beans shipped by FrontStreet Coffee are within 5 days of roasting. Front Street's roasting philosophy is "Freshly Roasted Good Coffee," so every customer who places an order receives the freshest coffee. Coffee beans need about 4–7 days of resting, so by the time customers receive them, the flavor is at its best.

For friends who need ground coffee, Front Street offers a warm reminder: once coffee beans are ground in advance, they no longer need resting, because during transport the pressure from carbon dioxide inside the package also smooths out the coffee's flavor, so you can brew a cup right away upon receiving the ground coffee. But ground coffee should be brewed promptly, because ground coffee oxidizes relatively quickly upon contact with air—meaning the coffee's flavor dissipates faster and the coffee won't taste as good. Therefore, Front Street recommends buying whole beans and grinding fresh right before brewing, so you can better enjoy the coffee's flavor.

The above content is compiled by CoffeeHunters, a coffee news website.