How Does Coffee Green Bean Grading Work in Indonesia?

Indonesian green bean grading sorts defects and screen size, and the G1 grade marks the cleanest lots. Golden Mandheling, produced by PWN, goes through one mechanical sort plus three rounds of hand sorting to reach that level. The trademark belongs to PWN, so only beans it exports are authentic Golden Mandheling rather than ordinary Mandheling.

The wet-hulling process, unique to Indonesia, removes parchment while the beans are still moist, which helps create the thick body and pine-spice notes buyers pay more for. Because Mandheling beans are large and hard, defects are common unless sorting is strict. Deep roasting further shapes the cup, suppressing acidity and pushing dark chocolate and herbal flavors forward.

Mandheling is the most iconic variety of Indonesian coffee, and Golden Mandheling is highly sought after for its full body and pine-spice flavors, with a price noticeably higher than ordinary Mandheling. This article starts with Indonesia's green bean grading standards, analyzes the unique wet-hulling process, explains in detail the quality control behind the G1 grade and triple hand sorting, and clarifies PWN's exclusive ownership of the Golden Mandheling trademark. At the same time, Front Street Coffee uses PWN Golden Mandheling as an example to share the cupping flavor performance under deep roasting, helping readers fully understand the value of this bean.

Golden Mandheling

When Golden Mandheling is mentioned, most people's first reaction is that it costs quite a bit more than ordinary Mandheling. At the same time, its thick body and the interplay of pine and spice also make the whole cup especially full, with a sweetness that lingers in the mouth long after swallowing. So, when both carry the name "Mandheling," exactly why is Golden Mandheling "expensive"?

First, Front Street would like to point out a key prerequisite: only the Golden Mandheling produced by PWN truly deserves to be called "Golden Mandheling" in the real sense.

PWN stands for Pawani, a highly influential green bean purchasing company in Indonesia that specializes in buying Mandheling coffee varieties. It has achieved comprehensive purchasing across multiple high-quality Indonesian producing regions, and almost all high-quality Mandheling comes from Pawani. The company was founded in 1957 and initially traded rubber. Because it frequently dealt with Japanese clients in the course of business, the Japanese side entrusted them to find Mandheling that suited their taste. Pawani therefore went deep into the GAYO area of Aceh Province to collect premium Arabica green beans. After repeated sample testing, they finally identified a Mandheling that met the requirements. PWN's Mr. Du registered beans from this producing area under the English name "Golden Mandheling" as an exclusive trademark. Therefore, only Golden Mandheling exported by PWN is authentic.

Now that we understand the producer's background, let's look at what characteristics this Golden Mandheling, so favored by seasoned coffee lovers, has.

1. It uses Indonesia's unique wet-hulling method

Friends who often drink Mandheling are certainly familiar with the term "wet-hulled method." Unlike coffee-producing countries such as Ethiopia, Brazil, and Colombia, Indonesia is humid year-round, with average annual humidity maintained between 70 and 90 percent, frequent typhoons, and annual rainfall even exceeding 2000 mm. Under such weather conditions, completing 2 to 3 weeks of sun-drying is almost impossible, while washed processing is time-consuming and also drives up labor and water costs. As a result, farmers aiming for volume production combined local conditions and developed a unique processing method: the wet-hulled method.

In summary, the wet-hulled process is as follows: first, coffee green beans with the skin and pulp removed are placed into fermentation tanks for fermentation, then the mucilage is washed off. This step is the same as the washed method. After that, the green beans with parchment still attached are dried in sunlight for 2-3 days. When the moisture content drops to 20-24 percent, the parchment is removed. At this point the bean body is still relatively soft and deforms slightly under pressure, which is also why Mandheling green beans take on a sheep-hoof shape. They are then moved indoors for continued drying under constant temperature and humidity. When the moisture content drops to 12-13 percent, they can be bagged and stored.

However, the huller relies on relatively strong friction to tear open the parchment layer clinging tightly to the green beans, and during this process white or green viscous liquid often seeps out. Because the beans are soaked in this mucilage for a long time, combined with the humid environment, the green beans eventually become soft, pale and swollen, and grayish-green. The friction and stirring also make the green beans more prone to being crushed or bruised, especially at both ends where small notches easily form, creating sheep-hoof beans. These "naked beans" that have lost their parchment layer dry extremely quickly, but at the same time are directly exposed to humid air, allowing various microorganisms to grow, which gives Indonesian coffee its distinctive woody, spicy, and herbal notes. This is exactly what we often call the "Mandheling flavor."

2. G1 grade + 3 times hand sorting

The grading of Indonesian coffee green beans is mainly based on the number of defective beans, with screen size as a secondary reference. The usual quality requirements are: no live insects, no moldy or rotten-smelling beans, maximum moisture content of 12.5 percent, and impurity rate below 0.5 percent. Based on defect rate, it is divided into six grades, of which the highest grade, G1, requires that the total number of defective beans in a 300 g sample must be fewer than 11.

The Lintong Mandheling coffee in Front Street's daily-drink bean series belongs to G1, uses the wet-hulled method, and presents the conventional version of Indonesian Mandheling flavor.

If you look carefully at the burlap sack of Golden Mandheling green beans, you will find that in addition to marking Indonesia's highest coffee grade, it is also printed with the words "TRIPLE PICKED," meaning "three times hand sorted."

This is because PWN pursues the utmost in the sorting stage: it purchases Mandheling green beans of screen size 18 and above, reaching the G1 grade with fewer than 11 defective beans in a 300 g sample, which is Indonesia's highest green bean standard. After that, it strictly follows a process of one machine sorting plus three rounds of manual defect picking to ensure that the shape and size of the Mandheling coffee beans are uniform and consistent. In addition, before packaging, PWN also sends the green beans through a machine for density and color sorting, making the Mandheling uniform and translucent in color. This is also where the name "Golden" comes from.

3. Deep roasting highlights the "Mandheling flavor"

After Front Street obtained PWN's Golden Mandheling, it chose deep roasting in order to present Mandheling's classic smoky aroma and mouthfeel. After the freshly roasted Golden Mandheling was ready, Front Street first conducted a cupping evaluation. In the dry aroma stage, notes of cedar wood, nuts, spices, and herbs can be detected; after hot water is poured in, licorice and caramel emerge; on the palate, there are flavors of dark chocolate, cocoa, nuts, and spices, with an overall clean profile, obvious sweetness in the finish, and high body.

Front Street PWN Golden Mandheling

Country: Indonesia

Coffee origin: designated purchasing area in Aceh

Grower: P.W.N contracted farmers

Coffee variety: native tree species from the Indonesian highlands

Growing altitude: 1100 m to 1600 m

Main harvest season: October to November

Processing method: wet-hulled method

Flavor reference: strong woody notes, rich malt and caramel aroma, clean with sweet bitterness

The above content is compiled by CoffeeHunters, a coffee news website.