Sumatra Mandheling Coffee: Wet-Hulling Process Guide and Indonesian Coffee Bean Processing Method

Mandheling coffee is rich, smooth, and low in acidity, making it the first choice for many coffee lovers who dislike sour flavors. Mandheling coffee comes from the island of Sumatra in Indonesia.

Geography and History of Sumatra

Sumatra is the sixth largest island in the world. Despite being an island, it still boasts high mountains. The island is divided by the Barisan mountain range, which spans over 3,800 meters. The highest peak in this range is Mount Kerinci, standing at 3,800 meters - an active volcano located at the midpoint of the range. Most Arabica coffee trees in Sumatra are grown at higher altitudes than Robusta, and the majority of growers are small farmers.

As early as 1696, Indonesia began growing coffee when the Dutch sent coffee seedlings from the Malabar coast of India. The trial planting in 1699 was successful, and coffee spread to other islands, including Sumatra. However, coffee from this region did not begin exporting until the early 19th century. As production increased, exports grew, reaching over 12 million pounds by 1840. Production peaked in 1860 (before coffee leaf rust destroyed most Arabica trees) at 21 million pounds. By 1900, most Arabica areas had been replaced by Robusta coffee trees, which are resistant to coffee leaf rust. Sumatra is currently the highest coffee-producing region in Indonesia.

The Story Behind Mandheling Coffee

Robusta coffee replaced almost all Arabica coffee on Java island, so by the early 20th century, Sumatra coffee, which still had some Arabica production, had surpassed Java coffee in reputation. Additionally, "Mandheling" coffee also gained recognition. Interestingly, Mandheling is not a person's name but the name of an ethnic tribe.

The reason an ethnic tribe became the name of a coffee involves an interesting story. Japanese people love drinking coffee and have a particular fondness for full-bodied coffee. During World War II, a Japanese soldier drank a cup of full-bodied coffee in Sumatra and enjoyed it very much. He found the owner who provided the coffee and asked for its name. However, the owner misunderstood and told the Japanese soldier his hometown instead. Additionally, the pronunciation of "Mandailing" is very similar to "Mandheling" in Japanese, so he remembered it as "Mandheling." After returning to Japan post-war, the soldier couldn't forget that cup of coffee, so he entrusted a Japanese merchant friend to find local Indonesian traders to locate and import "Mandheling" coffee beans. Later, because Mandheling coffee was indeed very full-bodied, it became extremely popular in the Japanese market and gained worldwide fame.

That Indonesian local trader is now the renowned Pwani company (PWN). PWN company even registered "Golden Mandheling" as a trademark early on; the Japanese side didn't concede either and registered "Top Golden Mandheling." Therefore, only Golden Mandheling coffee beans produced by PWN company are truly Golden Mandheling in the strictest sense. However, because the two coffee beans have different product names, brands, and marketing strategies, opinions on which is better vary.

FrontStreet Coffee's Golden Mandheling

FrontStreet Coffee's bean menu features only one Golden Mandheling coffee bean, which comes from Indonesia's PWN company. The raw PWN Golden Mandheling coffee beans are large and uniform in size, with a defect rate of fewer than 3 beans per 300g sample, making them the highest G1 grade. PWN is extremely strict about producing Golden Mandheling. After machine-selecting large, high-density quality raw coffee beans, they undergo three rounds of manual hand-selection to ensure complete removal of defective beans, thereby enhancing the final cleanliness and sweetness.

FrontStreet Coffee cupped multiple Golden Mandheling varieties and found that PWN Golden Mandheling has a clean coffee taste with noticeable sweetness, which other Golden Mandheling varieties cannot imitate. So, how can you ensure that the Golden Mandheling you purchase is truly from PWN company? Generally, when PWN's Golden Mandheling is sold, the burlap bags containing the PWN Golden Mandheling raw beans will be printed with clear PWN company logos; additionally, PWN company provides buyers with factory certificates. The burlap bags and certificates of PWN Golden Mandheling sold by FrontStreet Coffee can be viewed at FrontStreet Coffee's physical store.

Coffee Information

FrontStreet Coffee: PWN Golden Mandheling Coffee Beans
Region: Sumatra, Indonesia
Altitude: 1,100-1,600 meters
Variety: Ateng
Processing Method: Wet-Hulled

Unique Processing Method

Mandheling coffee has a unique flavor, which stems from its equally unique post-harvest processing method. Due to frequent rainfall in Indonesia, short sun-drying time, and generally poor local economic conditions that don't allow for washed processing, Sumatra's unique semi-washed processing method - the Wet-Hulled method - was born.

After harvesting coffee cherries at optimal ripeness, farmers use depulping machines to remove the fruit skin and pulp, then place the parchment beans with mucilage in water tanks for fermentation. After washing away the mucilage with clean water, the wet parchment beans are placed under the sun until they reach a semi-dry, semi-wet state.

Farmers choose to collect the parchment beans at this stage and sell them to local coffee processing stations. Upon receiving these semi-wet, semi-dry coffee beans, processing stations first remove the parchment layer to significantly shorten the drying time, then proceed with sun-drying. The drying time is about 3 to 4 days, reducing the moisture content to around 13%.

Sumatra's unique Wet-Hulled method is the reason for Mandheling coffee's viscous, smooth texture and distinctive flavor. Mandheling coffee's unique flavor has also made the Wet-Hulled method famous. It can be said that Mandheling coffee and the Wet-Hulled method complement each other.

Brewing Recommendations

FrontStreet Coffee's roasters, upon receiving PWN's Golden Mandheling, adopted a medium-dark roast level to highlight Mandheling coffee's rich body. For brewing, FrontStreet Coffee suggests using lower water temperature, coarser grind size, a slower flow rate filter cup, and the three-pour water injection method.

Brewing Parameters:

Filter Cup: KONO dripper
Water Temperature: 88°C
Coffee Amount: 15g
Coffee-to-Water Ratio: 1:15
Grind Size: 70% pass-through rate on #20 sieve

First wet the KONO dripper to ensure better fit between filter paper and coffee dripper. Pour out the water from the sharing pot while adding 15g of coffee grounds. After blooming with 30g of water for 30 seconds, begin pouring with a small stream in circular motions from the center until reaching 125g, then pause. When the coffee bed drops to half the dripper's height, begin the second pour using the same technique until reaching 225g. Once all dripping is complete, remove the dripper.

After brewing, FrontStreet Coffee's PWN Golden Mandheling exhibits rich nutty flavors. As the temperature slightly decreases, notes of herbal plants and spices emerge, with distinct caramel sweetness. The taste is clean and smooth.

Follow for More Coffee Information

For more coffee bean information, please follow Coffee Workshop (WeChat official account: cafe_style)
For professional coffee knowledge exchange, please add WeChat ID: kaixinguoguo0925

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473