Pour-Over Sumatra Coffee Bean Tutorial: How to Drink Sumatra Coffee and What's the Price Per Cup?

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As the largest island within Indonesia, Sumatra is bordered by the Indian Ocean to the west and the South China Sea to the east, with the equator passing directly through it. Additionally, it happens to be situated on the Pacific Ring of Fire, with volcanoes scattered throughout, bringing fertile volcanic ash soil to this land. The mountainous areas, perpetually shrouded in clouds and mist, possess considerable elevation. Combined with abundant rainfall and comfortable temperatures, this makes the land rich in resources, with coffee being one of the most suitable crops for cultivation.

The Origins of Indonesian Coffee

The beginning of Indonesian coffee dates back to the late 17th century when the Dutch conquered Java Island, making it the headquarters of the Dutch East India Company in the East. The Dutch successively introduced two batches of Typica seedlings from India to Java for breeding. Before the 1870s, coffee growing areas were established on Sumatra, Bali, Sulawesi, and Timor islands, soon expanding from the original Java Island throughout the entire Indonesian archipelago. However, this prosperity was short-lived. In 1869, the sudden outbreak of coffee leaf rust swept through the entire Asian coffee-producing region, including Indonesia, causing large areas of Typica trees to wither and die from infestation.

To save the devastated coffee plantations, the Indonesian government introduced more disease-resistant Robusta varieties from Africa and other regions. Robusta remains the main variety in Indonesia to this day. To ensure plant survival rates and increase coffee production, Indonesia continuously introduced various disease-resistant varieties from other countries. Among these, Tim Tim, Bor Bor, and the Catimor series Ateng—hybrids of Robusta and Arabica—gained prominence due to their excellent disease resistance, vigorous yields, and adaptation to Sumatra's terroir.

Soon, Ateng and Tim Tim gradually replaced the original Typica varieties, becoming the main cultivars in Sumatra and other regions. The most famous specialty coffee representative among them is Mandheling. Mandheling is primarily produced around two major lakes in Aceh and North Sumatra provinces: Lake Toba and Lake Tawar.

The Growing Regions

Lake Toba is the world's largest volcanic lake and also Indonesia's largest high-altitude freshwater lake. The average annual temperature here is around 22°C, belonging to a tropical rainforest climate. The rainy and humid environment, combined with an altitude of about 1,400 meters in the mountainous areas, produces various spices, timber, palm oil, and other agricultural products, including coffee of course. Under the misty and rainy weather, most fruit trees grow on the higher mountain slopes. Several types of ferns cover their surface, collectively providing good sun protection for the coffee, so growers don't need to adopt shade cultivation.

The Gayo Highlands, located in central Aceh Province of Sumatra, have a very unique microclimate environment near the famous volcanic Lake Tawar. The lake water here is clear, and the natural environment is excellent. Coffee trees are planted on mountains 1,200-1,800 meters high, surrounded by mist year-round. The significant temperature difference between day and night, volcanic soil rich in minerals and nutrients, and fallen fruit serving as fertilizer all contribute to the quality. Farmers widely use organic methods to grow coffee, and the long history of cultivation has resulted in higher quality and yield of coffee produced here. Many green coffee buyers also place special importance on this region, including the locally famous Pwani Coffee Company (PWN).

Each year from September to April of the following year is the coffee cherry ripening season, where you can see many farmers busy picking in the mountains. The traditional Lintong Mandheling is grown by the Mandailing and Batak ethnic groups, while the "rising star" Lake Tawar Mandheling is cultivated by the Gayo people.

Unique Processing Methods

The biggest difference from many coffee-producing regions is that Indonesia mostly has humid weather, with annual humidity between 70-90%. Typhoons can arrive unexpectedly, and annual rainfall can even exceed 2,000mm. Such harsh weather conditions simply cannot accommodate the 2-3 week sun-drying process used in Africa. Washed processing is not only time-consuming but also requires more labor costs and water resources, which Indonesia, focusing on mass production, cannot afford. Thus, they developed a unique semi-washed method—the wet hulling process.

Coffee cherries with pulp removed are directly poured into pools for brief fermentation of several hours. At this point, a small amount of mucilage still remains on the parchment layer, which is removed through brushing. Next, the parchment coffee is dried for the first time only until reaching 30-40% moisture content—about 2-3 days—before coffee farmers sell the green beans to buyers. The buyers will directly subject the purchased semi-dry parchment beans to mechanical hulling to obtain the innermost green beans.

Because the hulling machine uses greater friction to tear off the parchment layer tightly attached to the green beans, white or green viscous liquid usually flows out during this stage. Due to long-term soaking in this liquid and the humid environment, the final green beans become soft, pale and swollen, forming a gray-green color. Through the stirring action of friction, the green beans are also more easily crushed or bruised, especially at both ends, forming small gaps and creating what's known as "goat hoof beans." The "naked beans" without the parchment layer dry very quickly but are also directly exposed to the humid environment, allowing various microorganisms to proliferate. This gives the coffee its unique woody, spicy, and herbal plant aromas—what we call the "Mandheling flavor."

FrontStreet Coffee's Brewing Recommendations

Regarding coffee brewing, FrontStreet Coffee finds it necessary to remind everyone that if coffee beans are ground in advance, they need to be brewed promptly. Because coffee powder loses aroma relatively quickly when exposed to air, and the最终 brewed coffee flavor won't be as good. Therefore, FrontStreet Coffee recommends grinding immediately before brewing to better experience the coffee's optimal flavor.

In daily brewing of medium-dark roasted Mandheling, FrontStreet Coffee typically uses a KONO dripper. The KONO dripper makes the coffee taste more rounded and full-bodied, with flavor expression being more direct. However, the KONO dripper has relatively poor exhaust effectiveness because its ribs are straight and only extend one-quarter of the dripper's depth. Above this quarter point, the surface closely adheres to the cup wall, creating a sealed state.

Recommended brewing water temperature: 88-89°C. Bloom time: 25 seconds. Coffee-to-water ratio: 1:15. Grind size: medium-fine (75% pass-through rate on China standard #20 sieve).

Adopting segmented extraction, use twice the amount of coffee powder in water for blooming—that is, bloom with 30g water for 30 seconds. When the small stream reaches 125g, segment the pour. Continue pouring until reaching 225g, then stop. After the water in the dripper finishes dripping, remove the dripper. Time from the start of pouring: 2'00". Next, take the entire cup of coffee and shake it well before pouring into cups for tasting.

Frontsteet Mandheling Pour-Over Flavor Notes

[Lintong Mandheling] Herbal notes, chocolate, caramel, overall well-balanced;

[Gold Mandheling] Nuts, spices, herbal plants, licorice, chocolate, caramel, with clean and gentle flavors;

Important Notice :

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