Sumatra Mandheling Coffee Bean Varieties Introduction: Pour-Over Brewing Parameters and Flavor Profile

Coffee enthusiasts who are familiar with coffee beans may know that Mandheling coffee beans are relatively large and have what's known as "sheep hoof beans" (split beans). This is a distinctive characteristic of Mandheling coffee. This phenomenon occurs due to the wet-hulling processing method. When the semi-hard, semi-soft moist green beans are being hulled to remove the mucilage and parchment layer, they are easily bruised and split open, resembling sheep hooves. These are commonly called "sheep hoof beans" and are not considered defective beans. Mandheling coffee offers a heavy body, smooth texture, accompanied by grassy aromas and earthy notes, with a long-lasting aftertaste and almost no noticeable acidity.

The Origin of Mandheling Coffee

The name "Mandheling" is neither a coffee variety nor a producing region name. Instead, it refers to an ethnic minority group living in the northern highlands of Sumatra Island. During World War II, when Japan occupied Indonesia, a Japanese soldier tasted an incredibly fragrant coffee at a café. When he asked the owner for the coffee's name, the owner misunderstood and thought he was asking about his identity, so he replied: "Mandheling." After the war, when the soldier returned to Japan, he recalled the "Mandheling" coffee he had tasted in Indonesia. He arranged to import 15 tons of it from Japan, and it became extremely popular. The name Mandheling has been passed down ever since.

Indonesia's Sumatra Coffee Regions

Mandheling coffee is also known as Sumatra coffee because it grows on the island of Sumatra in Indonesia. Sumatra is not only Indonesia's largest island but also the world's sixth-largest island. It is located in northwestern Indonesia, extending from northwest to southeast, with the equator passing through its central region. The terrain is higher in the northwest, where the Barisan Mountains run through the area, primarily growing Arabica varieties as the main producing region for Mandheling. The southeast is lower, mostly flat or swampy land, dominated by Robusta varieties. The entire island has over 90 volcanoes and numerous volcanic lakes, providing fertile soil for coffee cultivation. Due to its geographical location, Sumatra has the earliest harvest season in the country—November to March.

Lintong Mandheling comes from the Lintong mountainous area in north-central Sumatra, near Lake Toba. Lintong Mandheling is essentially the standard version of Sumatra Mandheling.

Lake Toba, located in central North Sumatra Province, where Dutch colonialists moved "Java Mandheling" north to the Lake Toba area in 1888, creating the modern Mandheling legend.

Lake Tawar, located in central Aceh Special Autonomous Region. Situated at the northern tip of Sumatra Island, its area is less than one-tenth of Lake Toba's.

Currently, the highest quality beans from the entire Sumatra region come from the GAYO mountain area, mostly grown from old tree varieties. The Gayo Mountains are located in the Aceh region of northern Sumatra Province, at altitudes between 1500-2500 meters. Most coffee farmers are local indigenous people—the GAYO ethnic group. This region offers ideal growing conditions for coffee—high altitude, fertile soil, and abundant rainfall. Lake Tawar provides rich water resources, and the area widely adopts organic farming methods without chemical fertilizers, making it considered a world green coffee production area. Therefore, Gayo coffee is often called green coffee or Gayo organic coffee.

FrontStreet Coffee's new season Golden Mandheling coffee is produced in the GAYO mountains of Aceh, North Sumatra, and is the Golden Mandheling coffee beans from PWN company. Golden Mandheling has stricter quality requirements, first ensuring that the coffee beans are size 19, with full, uniform particles, belonging to the highest G1 grade. PWN beans are darker green in color and have neat, flat shapes. They then undergo one machine selection and three manual hand-picking processes to ensure that defective beans are fewer than 3 (in a 300g green bean sample).

Mandheling Coffee Varieties

The Indonesia region has a very long history of coffee bean cultivation. Previously, Arabica was grown, but due to leaf rust disease, currently 90% of coffee beans exported from Indonesia are Robusta varieties, with only 10% being Arabica coffee beans. FrontStreet Coffee's Lintong Mandheling coffee variety is TimTim Ateng, while the Golden Mandheling coffee variety is listed as: Ateng. In reality, TimTim is actually Timor, an Arabica variety with Robusta heritage, while Ateng is Catimor, a hybrid of Caturra and Catimor. These variety names are just local terminology.

Mandheling Coffee Bean Processing

Mandheling coffee beans are processed using the wet-hulling method. Some customers seeing Mandheling coffee beans might find them somewhat unattractive because they have gaps at both ends—what we commonly call "sheep hoof beans." These are not defective beans. This is because Indonesia is located near the equator, has a tropical rainforest climate, and mass-produced coffee beans mostly undergo rough wet-hulling processing. Wet-hulling greatly accelerates the entire processing process, but removing the parchment layer while still in a semi-dry state requires significant friction, making the green beans easily crushed and bruised, especially at the ends, forming small gaps.

FrontStreet Coffee's Mandheling Brewing Parameters

FrontStreet Coffee believes that to brew a good pot of coffee, one should focus on four main aspects: water temperature, grind size, coffee-to-water ratio, and brewing technique.

1. Water Temperature

When brewing pour-over coffee, FrontStreet Coffee chooses different water temperatures based on different roast levels. During roasting, substances contained within coffee beans are lost as the roast level deepens, so for dark roast coffee beans, temperature is reduced to avoid extracting excessive undesirable flavors. For light to medium roast beans, FrontStreet Coffee suggests using water temperatures of 90-91°C. For medium-dark roasts, FrontStreet Coffee suggests using water temperatures of 88-89°C.

This Mandheling coffee bean is famous for its rich, heavy-bodied flavor profile. To highlight Mandheling coffee's richness, FrontStreet Coffee uses medium-dark roasting to process it.

2. Grind Size

Coffee grind size is also related to roast level. Grind size refers to the size of coffee particles because it affects the contact time between coffee and water. If coffee grounds are finer, water can extract more substances in the same time, but finer grinds can easily lead to over-extraction during the brewing process. Conversely, coarser coffee grounds mean water extracts fewer substances in the same time, but overly coarse grinds can easily lead to under-extraction.

Additionally, since everyone's grinder is different, the parameters vary. Here FrontStreet Coffee recommends purchasing a #20 cupping calibration sieve with 0.85mm aperture. Take 10g of coffee beans, grind them to an approximate grind size, then pour into the sieve for screening. Weigh the screened coffee powder (make sure to sieve until no more coffee powder can pass through to complete the screening).

A screening pass rate of 70%-75% (7-7.5g from 10g powder) is the most suitable grind size. The pour-over grind size is: 80% for light roasts, and 75% for medium-dark roasts. If the pass rate exceeds the suitable range, appropriately adjust to a coarser grind size. If it doesn't reach the suitable pass rate, appropriately adjust to a finer grind size.

3. Coffee-to-Water Ratio

This is FrontStreet Coffee's hand-drip coffee ratio extraction parameters based on SCAA Golden Cup extraction theory, with differences in flavor profiles:

Rich Flavor: 1:10～1:11 (equivalent to Golden Cup standard 1:12.5～1:13.5)

Medium Flavor: 1:12～1:13 (equivalent to Golden Cup standard 1:14.5～1:15.5)

Light Flavor: 1:14～1:16 (equivalent to Golden Cup standard 1:16.5～1:18.5)

A coffee bean-to-water ratio of 1:14.5～1:15.5 most easily achieves the golden zone of 18%～22% extraction rate and 1.15%～1.35% concentration.

Therefore, FrontStreet Coffee suggests using the foolproof 1:15 coffee-to-water ratio when brewing this Mandheling coffee.

4. Brewing Technique

Finally, pour-over technique is also very important. Common techniques include three-stage brewing, single-pour, drip-by-drip, etc. Here FrontStreet Coffee recommends beginners use the three-stage pour-over method because this technique is suitable for light roast, light-to-medium, and medium-dark roast coffee beans. The segmented extraction method of three-stage pouring can clearly distinguish the front, middle, and back-end flavors of coffee, better ensuring the presentation of coffee flavors. Next, FrontStreet Coffee will teach everyone how to perform three-stage pour-over brewing.

Three-Stage Brewing Method (FrontStreet Coffee's Mandheling Three-Stage Brewing)

FrontStreet Coffee believes that the quality of Mandheling coffee lies in the balance of sweet, sour, and bitter notes, with high richness. In roasting, FrontStreet Coffee chose medium-dark roasting to highlight the coffee beans' nutty, pine, and herbal flavors. Using a KONO dripper can provide better richness. Water temperature 88°C, coffee-to-water ratio 1:15, 15g coffee dose, grind size (China #20 standard sieve pass rate 75%).

First Pour: Bloom (helps release gas)

First wet the KONO dripper to make the filter paper fit better with the coffee dripper. Pour out the water from the sharing pot and add 15g of coffee grounds. Use 30g of water to bloom for 30 seconds. Many coffee enthusiasts don't know why hand-drip coffee needs blooming. Actually, blooming is because coffee beans undergo a series of chemical and physical changes during the roasting process from green to roasted beans. After reaching a certain roasting level, coffee beans accumulate large amounts of gas (mostly carbon dioxide).

Generally, the fresher the coffee and the closer to roasting, the more bubbles typically appear during blooming. Dark roast beans also release more gas during blooming than light roast beans. FrontStreet Coffee's coffee beans are freshly roasted, so we generally recommend customers let the beans rest for three days first, allowing the coffee beans to release carbon dioxide first. This can avoid unstable extraction and under-extraction issues during brewing.

After blooming releases the gas, coffee particles can absorb water evenly, allowing for uniform extraction later. Good blooming allows coffee grounds to release gas quickly, thoroughly, and uniformly while also enabling full, rapid contact between coffee grounds and water, helping coffee grounds to be extracted evenly. These are the purpose and significance of hand-drip coffee blooming.

Second Pour

After 30 seconds of blooming, perform the second pour. Start with center-circling small water flow until reaching 125g, then stop. To concentrate the water column's penetrating power, keep the circular movement range small—about the size of a one-yuan coin—then circle outward. From the second pour, pay attention to water volume, trying not to exceed the height of the coffee bed. That is, when the water column approaches near the filter paper, you can stop pouring water.

Third Pour

Wait until the coffee bed drops to half the dripper's height, then start the third pour with the same technique until reaching 225g. Wait until all dripping is complete, then remove the dripper.

From the third pour, observe the rate at which the water level drops. Also start pouring from the center, circling, with water not exceeding the coffee bed height. At this time, you'll observe that foam proportion covers the entire surface. The third pour should increase the tumbling of coffee particles, causing all settled particles to tumble, thereby dissolving soluble substances.

The tumbling particles will begin to settle when water addition stops. At this point, rely on the flow rate created by the dropping water level to generate friction between coffee particles. Once water addition stops, coffee grounds sink, causing blockage, so pay special attention to the rhythm of adding water. If there are too many interruptions in water flow, it's equivalent to letting coffee grounds continuously soak in water, which will lead to astringent and undesirable flavors in the tail-end coffee extraction.

Start timing from the first pour, with extraction time of 2'00". Next, take the entire cup and shake it evenly, then pour into cups for tasting.

Coffee Flavor Profiles

PWN Golden Mandheling Coffee Flavor: The coffee has diverse layers overall, is rich and clean, with intense nutty and caramel aromas, chocolate notes, long-lasting aftertaste, and high balance.

Lintong Mandheling Coffee Flavor: Entry has intense herbal aroma, dark chocolate, caramel, with sweet aftertaste.

For professional coffee knowledge exchange and more coffee bean information, please follow Coffee Workshop (WeChat public account: cafe_style). For more specialty coffee beans, please add FrontStreet Coffee's private WeChat, ID: qjcoffeex

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473