Mandheling Special: How to Brew Mandheling Coffee | Coffee Workshop Study Room

The Origin of FrontStreet Coffee's Mandheling

Indonesia's main coffee producing regions include Sumatra, Java, and Sulawesi islands, with Sumatra's "Mandheling" being the most renowned.

Mandheling, also known as "Sumatra Coffee," has famous growing regions including: Aceh (Aceh region), Lintong (Lintong region), and Sidikalang (Sidikalang region). The Lintong area and Lake Toba region can be collectively referred to as Mandheling.

FrontStreet Coffee's Mandheling has a rich, bold flavor with intense body and vibrant, lively character. It's neither astringent nor acidic, with its body and bitterness fully expressed. The appearance of FrontStreet Coffee's Mandheling coffee beans might be considered the ugliest, but coffee enthusiasts say that the less attractive Sumatra coffee beans look, the better, richer, and smoother their taste becomes.

The Unique Wet Hulling Process of Mandheling

Wet hulling, also known as Wet Hulling or Giling Basah in the local language, is a traditional Indonesian coffee processing method. Despite its name sounding similar to wet processing (washed processing), these two methods produce distinctly different cupping profiles. Coffee processed using wet hulling typically has a thick, intense flavor with a very distinctive character.

Wet Hulling Processing Steps

① Remove the fruit skin and pulp, retaining the parchment and mucilage

② Ferment in water tanks

③ Wash away the mucilage

④ Sun-dry with parchment for 2-3 days until moisture content reaches 20-24%

⑤ Hull off the parchment

⑥ Dry the green beans until moisture content reaches 12-13%

⑦ Prepare for export

Why Use Wet Hulling?

a. Climate Reasons

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

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

In regular washed processing, drying occurs with the parchment intact to protect the green beans from external damage. However, we notice that wet hulling removes the parchment for the final drying stage, allowing direct sunlight exposure to the green bean surface, enabling coffee beans to 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 greater and faster economic returns. Wet hulling significantly reduced time spent on farms and greatly decreased labor costs. This aligned with the investor mindset of pursuing rapid profits and reducing costs, which also contributed to the promotion of wet hulling.

c. Defects and Kuku Kambing (Hoof Beans)

When wet hulling removes the parchment, the coffee's moisture content is still as high as 20-24%, whereas in other processing methods, coffee moisture content drops to 10-12% before hulling. In this "semi-dry" state, parchment tends to adhere to the green bean surface, making hulling more difficult than with "fully dry" beans, requiring greater friction during the hulling process.

However, on the other hand, "semi-dry" green beans are very fragile at this stage, with hardness far below that of "fully dry" beans, so the beans are more easily crushed and form small cracks. 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 employees for manual defect sorting, typically including DP (double picking) and TP (triple picking). FrontStreet Coffee's Mandheling, after triple picking, will have a lower defect rate than double picking.

Summary:

To summarize the flavor of wet hulling, aside from minor subtle differences, we generally believe that wet-hulled beans have earthy, smoky, and chocolatey flavors. The acidity is considered "low acid," with thickness that can seem somewhat heavy.

The low acidity comes from the shorter, less effective fermentation process and longer drying time. The "earthy" flavors and similar characteristics of wet-hulled beans are subject to various interpretations. Some say it's related to the coffee varieties used in wet hulling regions (Timor and Catimor lines: with Robusta heritage), some say it's the result of organic interaction between green beans and the environment, and some even attribute it to too many defective beans! Of course, there are quite a few...

What is "Golden Mandheling"?

Some friends who have run coffee shops for several years say that "Golden Mandheling" is aged Mandheling. Speaking of "Golden Mandheling," we must start with PWN. This abbreviation is often mixed with Mandheling coffee names; it's actually the abbreviation for a company: Pwani Coffee Company.

This company is a very famous coffee acquisition company in Indonesia, mainly acquiring Mandheling coffee. Almost all of Indonesia's best growing regions are acquired by them, so most beans from PWN Company are unique specialty coffees. FrontStreet Coffee's Golden Mandheling is a product from this company. After acquiring the green beans, they undergo multiple manual selections to choose plump, defect-free beans. Only these fine beans that seem to undergo pageant-like layered screening can be classified as FrontStreet Coffee's Golden Mandheling.

However, PWN Company has trademarked "Golden Mandheling," meaning that only Golden Mandheling produced by PWN Company can be considered genuine "Golden Mandheling" in the future. Many beans on the market not from PWN Company but labeled as Golden Mandheling should actually be called Specialty Mandheling.

"Golden Mandheling" is not some aged bean but simply a product name created by the company.

The Difference Between FrontStreet Coffee's Mandheling and FrontStreet Coffee's Golden Mandheling:

Coffee friends have asked, as coffee beginners, what's the difference between FrontStreet Coffee's Golden Mandheling and FrontStreet Coffee's Mandheling G1? I really can't tell the difference. For professional-level coffee connoisseurs and taste-sensitive coffee friends, drinking these two coffees simultaneously will reveal very obvious comparisons. The Golden Mandheling's sweetness and cleanliness, thickness, and wild spice notes are slightly superior to G1, which is one reason why Golden Mandheling is much more expensive than G1.

FrontStreet Coffee's Mandheling requires layered screening, which I believe is absolutely necessary. Its probability of defective beans is too high, plus its ugly appearance - sometimes even good beans look like defective beans. Every time I sort FrontStreet Coffee's Mandheling, I can pick out a handful of defective beans, but looking back at the defective beans, I feel they can't really be considered defective - their appearance is just so unattractive. However, roasted FrontStreet Coffee's Mandheling is like a caterpillar breaking out of its cocoon to become a butterfly - the roasted beans are very plump and quite pleasing to the eye.

FrontStreet Coffee's Golden Mandheling has a defect rate of 2% and is very beautiful.

What Kind of Bean is FrontStreet Coffee's Aged Golden Mandheling?

Aged coffee actually has a long history in Indonesia. Because early shipping wasn't so developed, transporting coffee from Indonesia to other countries took quite a long time. Over time, the originally moisture-rich fresh coffee beans gradually dried, and the addition of sea breeze created a very special flavor.

Due to advances in modern shipping greatly reducing transportation time, such special-flavored coffee has become a specially processed coffee bean. Processing aged beans is a technical skill that requires close monitoring during the aging process of the coffee beans. Warehouse humidity and temperature have standard requirements, and coffee green beans must be periodically turned to prevent differences in humidity between top and bottom or mold that would cause spoilage. The aging process is not about losing flavor but creating another flavor - and a pleasant one at that.

The Gayo Mountains are located in the Aceh region of northern Sumatra province. Most coffee farmers working locally in Gayo are native farmers. The word "Gayo" comes from a tribe in Indonesia's Aceh region. This area has ideal growing conditions, a long historical culture, and unique flavors. The region widely uses organic methods to grow coffee without chemical fertilizers and is considered a world green coffee production area. Therefore, Gayo coffee is often called green coffee or Gayo organic coffee.

In the specialty coffee system, Sumatra coffee is a fascinating existence. You see, the famous Mandheling is actually not the name of a growing region, nor the name of a coffee variety, and even its varietal origins are quite chaotic.

Ateng —

A hybrid between Arabica and Robusta, with several subtypes, widely grown in Sumatra and other Indonesian islands. Simply put, it's a branch of Catimor, with Ateng being the local name.

Djember —

Djember, when searched on Baidu, is a place name in Sumatra, sounding quite mysterious, but the variety is actually S-795. Because this variety was spread to the island by the Jember Coffee Research Center, locals call S-795 by this name.

What is S-795? It's a hybrid created by Indian botanists crossing the Typica mutant Kent with S-288.

What is S-288? It's a natural hybrid of Arabica and Liberica.

The lineage is truly chaotic!

TimTim —

This is Timor Hybrid, translated as Timor Hybrid, which is a hybrid of Arabica and Robusta. Our familiar Catimor is created by further hybridization with this.

Tim Tim — Longberry Mandheling

Tim Tim is a bean from Indonesia. Due to its elongated shape, many people call it horse face bean, while others call it long bean Mandheling. Actually, Tim Tim is not a pure variety but a natural hybrid between Arabica coffee trees and Robusta coffee trees. This variety was discovered on Timor Island in the 1940s and was cultivated due to its natural disease resistance. In the Americas, this variety is called Hybrido de Timor, abbreviated as Tim Tim, while in Indonesia this variety is also called Bor Bor.

FrontStreet Coffee's Mandheling Roasting

Comparing FrontStreet Coffee's Mandheling at three roast levels: light roast, medium-dark roast, and dark roast.

Brewing Equipment Selection: Hario V60

Bloom Duration: 25 seconds

1. Light roast: Fujiyama ghost tooth grinder 3.5, water temperature 90°C, water-to-coffee ratio 1:15

2. Medium-dark roast: Fujiyama ghost tooth grinder 4, water temperature 88°C, water-to-coffee ratio 1:15

3. Dark roast: Fujiyama ghost tooth grinder 4.5, water temperature 86°C, water-to-coffee ratio 1:15

Test Results

1. Light roast: Fruity acidity is obvious but comfortable on entry, slightly bitter, with saliva stimulation on both sides of the mouth, average smoothness.

2. Medium-dark roast: Very good balance, fragrant and thick, bitterness is more obvious, chocolate notes and slight sweetness are more prominent, licorice aroma is clear, smoothness is better than light roast, with strong aroma.

3. Dark roast: Almost no acidity, very heavy bitterness, improper roasting can also produce burnt flavors.

Where Do Over-Extraction or Under-Extraction Problems Mainly Occur?

Over-extraction symptoms: Coffee becomes too bitter and astringent, caused by water soaking coffee grounds for too long.

Under-extraction symptoms: Taste is rather thin, feeling like water and coffee are separate.

Different Equipment, Different Brewing Methods

The taste will also be different

Pour Over

1. Dripper: Hario V60

2. Water temperature: 88°C

3. Grind size: Fujiyama grinder setting 4

4. Roast level: Medium-dark roast

5. Bloom time: 25 seconds

Flavor: Multi-layered, clean, balanced, persistent caramel sweetness in the aftertaste

Specific technique: 15g coffee, Fujiyama ghost tooth grinder setting 4, V60 dripper, 88-89°C water temperature. First pour 30g water for 25s bloom, pour to 104g then pause, wait until powder bed water level drops to half before pouring again, slowly pour until 220g total, discard last 5g, water-to-coffee ratio 1:15, extraction time around 2:00

AeroPress

1. Water temperature: 85°C

2. Grind size: Fujiyama grinder setting 3.5

3. Roast level: Medium-dark roast

4. Bloom time: 2 times, first 20 seconds, second 50 seconds

Specific technique: Prepare AeroPress for standard pressing, recommend adding 20g coffee grounds, water-to-coffee ratio 1:17. First pour 83°C hot water to 100g, stir 3-5 times to fully wet coffee grounds, let rest 20s, add remaining hot water to 240g, let rest 40s, stir 5s, wait until 1 minute 50 seconds then insert plunger and press, total time 2 minutes 5 seconds.

Flavor: Rich, complex, prominent spice notes, fresh forest aroma

Siphon

1. Water temperature: 90°C

2. Grind size: Fujiyama grinder setting 3.5

3. Roast level: Medium-dark roast

4. Brew time: 30 seconds

Specific technique: Side heat extraction, recommend 20g coffee for 2 servings, water-to-coffee ratio 1:12, water level to mark 2, use post-addition method (add coffee after water boils). Add coffee after bubbles form, stir 4-5 times, extract for about 30 seconds then remove heat. Finally, stir 2 times and let coffee liquid fall naturally.

Flavor: Round, rich, prominent herbal and bitter notes, with prominent caramel sweetness

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473