What are the Flavor Characteristics and Processing Methods of Indonesian Mandheling Coffee Beans?

FrontStreet Coffee evaluates every coffee bean it procures through multiple stages, including roasting, cupping, and pour-over. With so many evaluation criteria for just a single cup of coffee, FrontStreet Coffee compares at least three different coffee beans from the same origin before finally listing any coffee bean from a particular region.

Understanding Mandheling Coffee's Deep Roast Profile

The reason why we commonly encounter Mandheling as a deep roast is twofold: first, due to its processing method and mixed varieties, this bean has a relatively high defect rate, and deep roasting perfectly masks this flaw; second, because Mandheling was primarily discovered and developed by the Japanese, who tend to prefer body-focused profiles in coffee tasting. This makes it easy to understand why Mandheling chooses deep roast. The Mandheling coffee discussed today has gained significant popularity in recent years. With its unique herbal and rich flavor profile, more and more people are accepting it. However, Mandheling origins are numerous, and quality varies greatly. FrontStreet Coffee has conducted extensive selection and evaluation, finally determining four Mandheling coffee beans: Gold Mandheling, Lintong Mandheling, Tiger Mandheling, and Aged Mandheling.

The Origin of Mandheling

Mandheling is not a region name, place name, port name, nor a coffee variety name. Its name is a phonetic translation of the Indonesian Mandheling ethnic group.

During World War II when Japan occupied Indonesia, Japanese soldiers tasted delicious local coffee. After returning to Japan, they couldn't forget the delicious local coffee, so they enlisted the help of trading friends to ask locals to collect quality coffee beans, including this Mandheling. The Japanese loved this coffee bean and asked for its name. Since the business source couldn't be conveniently disclosed, the locals casually mentioned "Mandheling," and thus Mandheling accidentally became the name of a coffee bean.

The locals mentioned earlier are actually the owner of Indonesia's PWN company (Pawani Coffee Company), from whom FrontStreet Coffee sources its Gold Mandheling coffee beans.

What is Mandheling Coffee

Indonesia's main coffee-producing regions include Sumatra, Java, and Sulawesi islands, with "Mandheling" from Sumatra being the most famous. Mandheling is also known as "Sumatra Coffee." Coffee from Lake Tawar in the north can be called Aceh Coffee or Lake Tawar Coffee, while Lintong and Lake Toba areas can be called Mandheling. Traditionally and strictly speaking, only coffee beans produced in the Lake Toba area (northwest of Sumatra Island, Indonesia) are called "Mandheling."

Mandheling has a strong flavor with rich body and vibrant, lively characteristics - neither astringent nor acidic, with body and bitterness fully expressed. The appearance of Mandheling coffee beans can be said to be the ugliest, but coffee enthusiasts say that the less attractive Sumatra coffee beans look, the better, richer, and smoother they taste.

Common Varieties of Mandheling

Here we showcase FrontStreet Coffee's four varieties of Mandheling: Lintong Mandheling, Gold Mandheling, Tiger Mandheling, and Aged Mandheling.

1. Lintong Mandheling

A specialty Mandheling produced in the Lintong region, with relatively large beans and hard bean structure.

Indonesian coffee quality is quite diverse, but what we commonly refer to as Mandheling typically refers to Typica or its variants grown in the mountainous areas surrounding Lake Toba. Coffee gourmets from around the world have evaluated that Sumatra Mandheling coffee is the coffee with the best texture in the world. Mandheling coffee beans are relatively large with hard structure, and due to more defects, they require strict selection during coffee processing.

Mandheling coffee is an indispensable variety for coffee blending and mixing. It has rich coffee flavor, sweet fragrance, pure bitterness, and richness, with a slight sweetness and mild acidity.

FrontStreet Coffee Indonesia Lintong Mandheling Coffee Beans

2. Gold Mandheling

Gold Mandheling is trademarked by Indonesia's PWN company, making it exclusive to PWN. Gold Mandheling is produced in Gayo Mountain, Aceh, North Sumatra. The variety is Ateng, which is a hybrid between Arabica and Robusta, widely grown in Sumatra and other Indonesian islands. It's actually a branch of Catimor, with Ateng being the local name. Gold Mandheling, sized at 19 screen, undergoes four manual selections with higher quality requirements.

FrontStreet Coffee Indonesia Gold Mandheling Coffee Beans

3. Tiger Mandheling

Only Mandheling beans with screen size 17 or above and defect rate below 4% can be called Tiger Mandheling. Since Tiger Mandheling's main varieties are Caturra and Typica. Caturra has citrus and lemon acidity in flavor, while Typica has persistent sweet aftertaste, making Tiger's taste more balanced and cleaner.

FrontStreet Coffee Indonesia Tiger Mandheling Coffee Beans

4. Aged Mandheling

Aged coffee beans don't mean simply leaving green coffee beans for a long time, as this is not acceptable because green coffee beans will still spoil after extended storage, changing from fresh green to white, then to yellow, becoming tasteless, and even growing insects. Like aged wines, green beans must undergo proper processing and long-term storage before they can be called truly aged coffee.

So-called aged coffee beans mean: using extended storage time to achieve natural aging (usually 2-3 years), with changes including reduced acidity, color changes, and thickened bean structure. Storage environment must be cool and ventilated. Because the storage environment is relatively dark and the time is longer, aged coffee always has complex flavors similar to mold or what's commonly called burlap or leather.

FrontStreet Coffee Indonesia Aged Mandheling Coffee Beans

Mandheling Coffee Processing Method

Mandheling's unique Wet Hulling method, also called Giling Basah in the local language, is a traditional Indonesian coffee processing method. Judging from the name alone, Wet Hulling seems similar to wet processing (washed processing), however, the cupping flavors of these two processing methods are completely different. Coffee processed with Wet Hulling is usually rich and intense, with a very distinct personality.

17th-century Dutch colonists first introduced coffee to Indonesia. These colonists pursued more and faster economic returns, and Wet Hulling greatly shortened the time spent on farms while significantly reducing labor costs. FrontStreet Coffee believes that the emergence of Wet Hulling coincided with the investor mentality of pursuing quick profits and reducing costs. This was also a driving force behind the Wet Hulling method.

Wet Hulling Processing Steps

① Remove skin and pulp, keeping parchment and mucilage
② Ferment in water tanks
③ Wash away mucilage
④ Sun-dry with parchment for 2-3 days until moisture content reaches 20-24%
⑤ Hull off parchment
⑥ Dry green beans until moisture content reaches 12-13%
⑦ Prepare for export

Wet Hulling creates Mandheling's special flavor. FrontStreet Coffee believes that Mandheling and Wet Hulling have a bound relationship, but today's coffee market is no longer satisfied with the status quo. Even though Wet Hulling is Mandheling's characteristic, other processing methods will be tried. FrontStreet Coffee recently introduced a Mandheling coffee that uses natural processing. This natural-processed Mandheling has a very different flavor profile from what we know of Mandheling. This one leans toward fruity notes with sweeter taste and soft fruit acidity.

FrontStreet Coffee: Sumatra Wahana Estate Natural Mandheling
Coffee Region: Lake Toba
Altitude: 1000 to 1700 meters
Soil: Volcanic soil
Coffee Varieties: Bourbon, Typica
Processing Method: Natural Processing
Harvest Year: 2020
Grade: G1

Coffee Region

Wahana Estate was established in 2005, located near LeaMungkur village in the Sidikalang region of northern Sumatra, Indonesia. Sidikalang has been one of Indonesia's famous coffee-producing regions since ancient times. The area where Wahana Estate is located has an altitude between 1200-1500 meters, annual rainfall of 2000-3000 mm, and additionally has a relatively cool climate with day-night temperature differences exceeding 10°C. Based on these conditions, Wahana's red cherries all have sugar content above 13%.

Wahana Estate is still a relatively young estate that continues to develop year by year. The estate covers an area of approximately 500 hectares. The estate owner plans to expand the coffee planting area as much as possible in the coming years. A large portion of Wahana Estate is covered by protected forest reserves, which include many native plant and tree species around valleys and rivers. Afterward, coffee seedlings are planted in already divided planting areas and carefully marked for future variety identification.

Currently planted local seedling varieties include: Long Berry from Aceh, Toraja from Sulawesi, Rasuna from Sumatra, S795 anddong Sari from Java. International nursery varieties include Villa Sachi from Costa Rica, Caturra from Costa Rica, Catuai from Costa Rica, and Typica from Colombia.

To produce high-quality North Sumatra province coffee, Wahana Estate plants shade trees and uses organic fertilizers (compost) on the farm, practicing sustainable agriculture. Wahana Estate isolates different coffee varieties by plot and harvests them separately to release the potential of each variety. Additionally, only red fruits can be harvested and then processed separately.

Processing Method

This bean's processing method is not Indonesia's unique Wet Hulling, but rather the more difficult natural processing method. The natural processing process first requires manual selection of defective coffee beans and immature or overripe coffee fruits. Afterward, the coffee fruits are evenly spread on drying grounds and need to be turned several times daily.

The drying process usually lasts about 2-3 weeks, depending on local climate, while Indonesia's humid and rainy climate makes this time longer. When the moisture content inside the coffee beans drops to 11-13%, the natural drying step is complete. The dried coffee fruit shells have become hard and dry, and only need to be hulled off with a hulling machine.

Brewing Suggestions

Wahana Estate Natural Mandheling coffee uses light roast. We recommend using a V60 dripper, water temperature around 90°C, water-to-coffee ratio of 1:15, coffee dose of 15g, and grind size slightly finer than Lintong Mandheling, similar to sugar granules (Chinese standard 20 mesh sieve with 80% pass rate), to extract more coffee bean flavor.

FrontStreet Coffee uses staged extraction, generally using bloom water that is 2 times the coffee amount, meaning 30g of water for 30 seconds bloom. After small stream circular pouring to 125g, segment, and when water level drops about to expose the coffee bed, continue pouring to 225g then stop. The entire extraction time is 2 minutes.

Flavor description: Entry has tropical fruit sweet and sour sensation, with obvious fermented aroma, smooth mouthfeel, tropical fruits, moderate acidity, and obvious sweetness.

Green Bean Comparison

Careful observation of green beans reveals that Mandheling beans have quite a few "sheep's hoof" beans (broken beans), which is caused by hulling when the beans have high moisture content and soft structure.

Gold Mandheling: Screen size is 19+, so the beans are noticeably larger than other Mandheling beans. Due to higher moisture content, the green beans tend to be darker green.
Tiger Mandheling: Green beans are round in shape, slightly yellow with green, with good uniformity.
Lintong Mandheling: Green beans are gray-green, with varying sizes - relatively not very uniform.
Aged Mandheling: Due to the processing method, green beans have a special color - orange leaning to black, with wrinkled surface appearance, and relatively uniform green bean size.

Roasting Comparison

FrontStreet Coffee's roasting goal is to reflect the flavor characteristics of the coffee's origin. In fact, each coffee bean can be roasted in various ways, but FrontStreet Coffee believes that the roasted flavor should embody the characteristics of that origin. For example, Yirgacheffe should have Yirgacheffe's flavor, and then develop other possibilities based on this foundation. This is FrontStreet Coffee's only standard for determining coffee roasting.

1. Lintong Mandheling

FrontStreet Coffee's roasting goal for this bean is medium-dark roast, to remove excessive acidity and enhance its body and balance. Lintong Mandheling beans have only medium altitude and very soft bean structure. To remove excess moisture and avoid astringency from insufficient dehydration, a roasting approach of extended dehydration time with heat reduction sliding was adopted.

Entry temperature 200℃, yellowing point at 5'18", first crack begins at 9 minutes, temperature 186℃, first crack development 4 minutes, discharged at 202℃.

2. Gold Mandheling

FrontStreet Coffee believes that Gold Mandheling belongs to green beans with higher moisture content, with relatively large deviation from natural beans in moisture, so special attention is needed during dehydration. For green beans with high moisture content, you can immediately close the damper after putting in the beans, steam for 30 seconds then open to 3, until the green beans turn light green or white, open damper to 4, open to 5 (maximum) after first crack.

Entry temperature 200℃, yellowing point at 5'40", first crack begins at 9'54'', temperature 191.2℃, first crack development 3'30'', discharged at 204.5℃.

3. Tiger Mandheling

Tiger Mandheling beans are round in shape, green with yellow, with good uniformity and high moisture content. FrontStreet Coffee's roasting goal for this bean is medium-dark roast, to remove excessive acidity and enhance its body and balance.

During roasting, because this bean's altitude is only medium and bean structure is very soft, to remove excess moisture and avoid astringency from insufficient dehydration, a roasting approach of extended dehydration time with heat reduction sliding was adopted. Heat was reduced at the yellowing point, after dehydration completion, and before first crack respectively to avoid surface scorching, and discharging was chosen at 4 minutes after first crack ends and 20 seconds before second crack begins, extending caramelization time to reflect its excellent cleanliness and sweetness.

Entry temperature 200℃, yellowing point at 5'18", first crack begins at 9 minutes, temperature 186.2℃, first crack development 4 minutes, discharged at 203℃.

4. Aged Mandheling

Because Mandheling green beans have high density and aged beans have less moisture, heat adjustments at various stages must be particularly careful. For Mandheling coffee, be careful not to scorch the oils on the original bean surface.

Entry temperature 200℃, yellowing point at 5'35", first crack begins at 9'30'', temperature 186.8℃, first crack development 3'20'', discharged at 197.5℃.

Cupping Comparison

Lintong Mandheling: Herbal, chocolate, caramel, overall relatively balanced.
Gold Mandheling: Nuts, spices, herbal plants, licorice, chocolate, caramel, clean and soft flavor.
Tiger Mandheling: Nuts, cream, dark chocolate, caramel, traditional Chinese medicine, obvious sweetness, relatively clean and clear flavor.
Aged Mandheling: Ripe pu-erh tea, caramel, herbal, chocolate, lower acidity.

How to Pour-Over Four Mandheling Coffee Beans with KONO Dripper

FrontStreet Coffee uses pour-over brewing method while maintaining consistent brewing parameters to compare the flavors of four Mandheling varieties.

For daily Mandheling brewing, FrontStreet Coffee recommends using a KONO dripper because it produces a rounder and richer mouthfeel with more direct flavor expression. The KONO dripper's only exhaust area is the one-quarter rib section. When water level passes the rib section, water in the dripper continuously rises, increasing pressure through water weight. Since the outlet is relatively smaller, it prolongs the contact time between coffee particles and water. As water flows, this can more effectively extract soluble substances. FrontStreet Coffee's brewing method can generally achieve the high body expected by customers.

FrontStreet Coffee uses staged extraction, using 30g of water for 30 seconds bloom. When small stream circular pouring reaches 125g, segment, and when water level drops about to expose the coffee bed, continue pouring to 225g then stop pouring. When water level drops about to expose the coffee bed, remove the dripper (timing starts from bloom). Extraction time is 2'00".

Four Mandheling Coffee Bean Brewing Flavors

Lintong Mandheling: Herbal, chocolate, nuts, toasted bread
Gold Mandheling: Spices, nuts, pine, chocolate, caramel
Aged Mandheling: Ripe pu-erh tea, chocolate, caramel, herbal plants
Tiger Mandheling: Nuts, cream, dark chocolate, brown sugar, caramel

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