The Evolution of Coffee Bean Varieties in Indonesia's Sumatra and Sulawesi Islands

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Indonesia: The Archipelago of Coffee

Indonesia consists of over 17,000 islands scattered across the volcanic belt near the equator, with fertile soil. Famous growing regions include Sumatra in the west, Sulawesi in the central region, and Java in the south. Coffee was first brought to Jakarta in 1696 by the Dutch governor from Malabar, India, where local farmers were forced to reduce white rice production and switch to coffee cultivation. Since 1850, the Dutch East India Company expanded cultivation to other Indonesian islands. To date, Indonesia is the world's fourth-largest coffee exporting country.

The Rust Disease Crisis

The rust disease that ravaged Indonesia in 1876 nearly wiped out Arabica coffee. Since then, farmers in the severely affected lowlands of East Java began planting the highly disease-resistant Robusta variety. After the country gained independence, locals resumed cultivating the higher-quality Arabica. Today, 80% of Indonesia's exports remain commercial-grade Robusta. Interestingly, because Timor and Flores islands in the east were Portuguese territories at the time, the varieties planted differed from those in Dutch territories and were less affected. It's still possible to taste "heirloom varieties" originating from the 16th century today.

Regional Diversity

Indonesian coffee quality is highly diverse, with most coffees marketed by their island of origin: such as Sumatra, Sulawesi, Java, or Timur. The advantage of Indonesian coffee is that most varieties feature rich, restrained flavors and lively acidity. The drawback is that they may also have uncomfortable astringency or slight musty notes. Others display earthy characteristics that some coffee enthusiasts appreciate while others may dislike these qualities.

Bean Varieties Reflect Cultivation History

Sumatra coffee is most famous for Mandheling. This brand name, which is neither a bean variety nor a growing region, comes from a mistranslation of a tribal name (Mandailing). In Gayo Highlands of Aceh province, and the Lintong growing area surrounding the northern volcanic Lake Toba, also produce excellent Mandheling. Names include "Green Treasure" and "Blue Eye," with colorful descriptions. Sumatra coffee generally has a smooth taste, dense body, low acidity, with notes of earth, cedar, tobacco, and cocoa.

Sulawesi Island has existed for over 100 million years, so its soil contains richer mineral content than other Indonesian islands, producing coffee with brighter flavors. The production near Tana Toraja Mountain is most famous. It has slightly spicy flavors, including pepper, cinnamon, and nuts.

The evolution of Indonesian coffee bean varieties reflects the country's cultivation history. Indonesian coffee has many defects, with the main cause being improper processing. Whether using washed or natural methods, African and Central American farmers keep beans in parchment-like husks during processing, only removing them with threshing machines before export. However, Indonesia's popular Wet Hull (Giling Basah) processing method involves removing the parchment immediately after washing off the mucilage layer, without waiting for proper drying. The still-wet coffee beans contain up to 50% moisture. Middlemen collect the coffee beans from various sources and dry them under uncontrolled conditions: exposure to direct sunlight causes loss of organic acids, while drying on muddy ground risks the beans absorbing muddy flavors and dirt. This all stems from farmers seeking quick profits and lacking proper knowledge.

Brewing Recommendations

FrontStreet Coffee recommends brewing Indonesian coffee with 88°C water to bring out flavors of herbs, chocolate, and caramel.

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