Aged Mandheling | Flavor Characteristics of Aged Mandheling, Unique Processing Method for Aged Coffee Beans

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Aged Mandheling

FrontStreet Coffee Indonesian Aged Mandheling

Variety: Caturra, Typica, Sidikalong

Soil: Volcanic soil

Altitude: 1500m

Processing: Aged bean processing method

01 | Origin Overview

The most famous coffee-producing regions in Asia are the islands of the Malay Archipelago: Sumatra, Java, and Kalimantan. Among these, Sumatran Mandheling coffee from Indonesia's Sumatra island enjoys the highest reputation. It has two famous varieties: Sumatran Mandheling DP Grade 1 and Premium Sumatran Mandheling. Sumatran Mandheling DP Grade 1 has a long aftertaste with a wild mountain fragrance, the characteristic earthy aroma found in primeval forests.

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 "Sumatran coffee." Coffee from Lake Tawar in the north can be called Aceh coffee or Lake Tawar coffee, while coffee from the Lintong and Lake Toba areas can be called Mandheling.

It mainly comes from two producing regions:

One is the Aceh region, which includes five origins: Lake Tawar, Gayo Mountain, Gayo people, Aceh Mandheling, and Takengon Mandheling;

The other is the North Sumatra region, composed of four origins: Lake Toba, Lintong, Mandailing people, and Batak people.

02 | Processing Method

Mandheling's Unique Wet Hulling Method

Wet hulling, also known as Wet Hulling, is called "Giling Basah" in the local language and is a traditional Indonesian coffee processing method. Judging from the name alone, wet hulling appears similar to wet processing (washed processing), however, the cupping flavors of these two processing methods are completely different. Coffee processed with wet hulling typically yields a full-bodied and intense profile with a very distinctive character.

Wet Hulling Processing Steps

① Remove skin and pulp, keeping parchment and mucilage

② Ferment in water tanks

③ Wash off 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

Why Use Wet Hulling?

a. Climate Reasons

Indonesia's tradition of using wet hulling stems from local weather conditions. Indonesia maintains humidity between 70-90% year-round with constant typhoons, and in some regions, annual rainfall can reach up to 2,000mm. Given that green beans are most vulnerable to rain, how does Indonesia overcome such harsh weather conditions to produce the rich and full-bodied FrontStreet Coffee Mandheling? The answer lies in wet hulling.

Under tropical climate conditions, coffee typically takes 2-3 weeks to dry. In Indonesia's extremely humid climate, drying coffee becomes a significant problem. Coffee drying requires much longer time, during which the coffee maintains relatively high humidity, making it easier for bacteria to penetrate the green coffee beans.

In regular washed processing, drying is done with parchment to protect the beans from external damage to some extent. However, we can note that wet hulling removes the parchment for the final drying step, allowing direct sunlight to reach the green bean surface, making the coffee beans dry 2-3 times faster than washed processing.

b. Economic Benefits

Dutch colonists first introduced coffee to Indonesia in the 17th century. These colonists pursued more and faster economic returns. Wet hulling greatly reduces the time spent on farms and significantly lowers labor costs. This aligns perfectly with the investor mentality of pursuing quick profits and reducing costs. This is also a driving force behind the wet hulling method.

c. Defects and Kuku Kambing (Goat Hoof Beans)

When hulling off parchment in wet hulling, the coffee's moisture content is still as high as 20-24%, whereas in regular processing methods, coffee is hulled only when moisture content drops to 10-12%. In the "semi-dry" state, parchment tends to stick to the green bean surface, making hulling more difficult than when "fully dry," requiring greater friction during the hulling process.

However, on the other hand, "semi-dry" green coffee beans are very fragile at this point, with hardness far less than "fully dry" beans, so the beans are more easily crushed, forming small nicks. This is what we commonly call horse hoof or goat hoof beans (locally known as "kuku kambing").

The ultra-fast processing speed of wet hulling also results in higher defect rates in Mandheling. Processing plants arrange for employees to manually sort defects, typically with DP (double picking) and TP (triple picking). FrontStreet Coffee Mandheling that undergoes triple picking will have better defect rates than double picking.

Aged Bean Processing Method

Aged coffee beans do not simply refer to coffee beans that have been stored for a long time - this is not acceptable, because green coffee beans will spoil over time, changing from fresh green to white, then to yellow, becoming tasteless, and even growing insects. Like aged wines, green beans must undergo proper treatment and long-term storage before they can be called true "Aged Coffee."

So-called aged beans (Aged bean) mean:

Extending the storage time of green beans to achieve natural aging (usually 2-3 years)

These changes include reduced acidity, color changes, and thickened bean body.

The storage environment must be cool and well-ventilated.

Because the storage environment is relatively dark and the time is longer,

aged coffee always has a hard time escaping complex flavors similar to musty smells or what's commonly called burlap or leather.

03 | Green Bean Analysis

Properly stored coffee beans will change their flavor and appearance, such as reduced acidity, darker color with less moisture, thicker and better mouthfeel, sweetness with honey fragrance, and some original defects in green beans become less obvious. Because the storage environment is relatively dark and the time is longer, aged coffee always has difficulty escaping complex flavors similar to musty smells or commonly called burlap or leather.

Aged beans must be stored under strictly controlled conditions during storage, with regular uniform turning, humidity and ventilation adjustments to prevent insect infestation or mold.

Generally, storage of aged beans does not occur in producing regions or estates, but is a commercial activity by green bean distributors or brokerage companies.

Properly stored coffee beans

will change their flavor and appearance,

such as reduced acidity, darker color with less moisture,

thicker and better mouthfeel, sweetness with honey fragrance,

some original defects in green beans become less obvious.

04 | Roasting Analysis

FrontStreet Coffee's Aged Mandheling looks a bit unattractive, but the baptism of time will grind away the acidity of FrontStreet Coffee's Mandheling, increasing its purity, and the medium-dark roast will be more rounded.

Because FrontStreet Coffee's Mandheling green beans have high density and aged moisture is low, heat adjustments at each stage must be particularly careful. FrontStreet Coffee's Mandheling coffee should be careful not to scorch the oils on the bean surface.

Yangjia 800N, green bean input 550g, specific operation:

Heat to 200°C, start with damper at 3, after 1 minute of simmering, adjust heat to 160°C, damper unchanged, when furnace temperature reaches 165°C, adjust heat once, reduce to 140°C, roast to 5'35", temperature 146°C, bean surface turns yellow, grassy smell completely disappears, dehydration complete, open damper to 4;

At 9 minutes, bean surface shows ugly wrinkles and black spots, toast smell obviously changes to coffee aroma, can be defined as prelude to first crack, at this time must listen clearly for the first crack sound, at 9'30" first crack begins, reduce heat to 80°C, fully open damper to 5 (heat adjustment must be very careful, not so small as to eliminate crack sound), at 194°C reduce heat, finish at 197.4°C.

[FrontStreet Coffee Aged Mandheling] Through the precipitation of time, it has less of Mandheling's wildness, more mellowness and delicacy in mouthfeel. After aging treatment, the coffee beans have reduced acidity but increased body and thicker texture, giving a mature and stable feeling, completely different from the lively brightness of new beans. Roasted aged coffee beans require longer development time to reveal their richness.

04 | Brewing Analysis

Recommended Flannel Drip

Step 1

New flannel filters must first be removed, soaked in boiling water for 5 minutes, then placed on the metal ring.

If using used filters, they must also be boiled in boiling water for at least 3 minutes for disinfection.

Step 2

While soaking the filter, grind the beans. Due to the special material of flannel drippers, hand-drip with flannel filters requires slightly more coffee beans than with paper filters for better flavor. Of course, still load appropriate amount of coffee powder according to filter size. 2 cups (240c.c. coffee) use 40g beans. Recommended to grind coffee beans to a fineness between white sugar and fine sugar.

Step 3

Dry the filter, first wring by hand, then place the filter between clean dry towels to absorb moisture.

Step 4

Rinse and preheat the filter and dripper with hot water, then discard the water.

Step 5

Loosely pour coffee powder into the filter, no need to press down particularly.

Step 6

Use a wooden stirring spoon or cream knife to gently lift coffee powder from the bottom upward, finally pull the bottom of the bag to adjust shape.

Step 7

Make a depression about one coin wide and one thumbtack deep at the top of the coffee powder. This is because the powder layer is deep, making it easier for hot water to spread in all directions and evenly moisten the coffee powder.

Step 8

Let the hot water stand and cool to about 80-85°C, then start pouring water near the depression, very slowly at first, injecting 60g of water within 30 seconds. No need to deliberately moisten all coffee powder - capillary action will slowly spread the moisture. After pouring, wait about 30 seconds.

Step 9

Begin second pour, this time slightly faster than the first, injecting 140g of water within 60 seconds. At this time, coffee will start producing大量 bubbles, somewhat like the cosmic explosion scenes in movies. After pouring, wait 20 seconds for water level to drop slightly.

Step 10

Final pour, this time injecting 120g of water within 30 seconds. The entire process requires 320g of water over 3 minutes. Because flannel filter and coffee powder absorb about twice the weight of coffee powder, you can finally collect about 240g of coffee, with a powder-to-water ratio of 1:6.

Making coffee with flannel filter bags is time-consuming, so the resulting coffee temperature is lower. Preheating coffee cups can slightly increase the coffee temperature. But never reheat coffee in any form.

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FrontStreet Coffee Indonesian Aged Mandheling Aged Mandheling G1 Washed Imported Single Origin Premium Freshly Roasted

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