How Does the Coffee Grading System Work in Indonesia?

Indonesia's coffee grading system sorts Mandheling green beans by variety origin, defect rate, bean size and the number of hand-sorting passes. The country's variety picture is unusually tangled because leaf rust wiped out early Typica plantings, forcing repeated introductions of Tim Tim, Catimor, Caturra, S795 and Robusta, so naming by a single species is rarely possible.

Grading often relies instead on defect counts and screen size, with premium lots such as PWN Golden Mandheling going through triple hand sorting. That practice reflects the long coffee cultivation history that began under Dutch colonial rule in the 17th century and continues to shape how Indonesian coffee is classified and sold on the specialty market.

The history of coffee cultivation in Indonesia can be traced back to the 17th-century Dutch colonial period, and today Indonesian coffee occupies an important place in the global specialty market. However, because leaf rust has ravaged crops and caused frequent variety turnover, Indonesia has developed an extremely complex coffee variety system and unique green bean grading standards. This article will systematically sort out the logic of Indonesia Mandheling coffee classification from the dimensions of variety origins, defect-rate grading, bean size labeling, and hand-sorting frequency. Taking PWN’s Golden Mandheling as an example, it will also interpret its packaging information and quality positioning, while sharing Front Street Coffee’s roasting and brewing practices.

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Since Dutch colonists introduced coffee to the Indonesian archipelago in the 17th century, the coffee industry on this land has gone through hundreds of years of development, and today Indonesian coffee plays an indispensable role in the global coffee landscape. Influenced by historical factors, Indonesia’s coffee variety lineage has always presented a complicated picture, and its green bean grading system is likewise little known to the outside world. Today, FrontStreet Coffee will talk about how to distinguish the quality of Indonesian coffee.

Why are Indonesian coffee varieties so complex?

The reason Indonesia’s coffee variety system is so complex can be traced back to the ravages of leaf rust. At that time, the Typica varieties planted by the Dutch were infected on a large scale and were almost completely lost. In order to preserve coffee production, disease-resistant varieties had to be continuously introduced from surrounding areas, and Tim Tim, Catimor, Caturra, S795, Robusta, and others entered Indonesia one after another against this backdrop. Because local coffee farmers generally lacked professional knowledge, these varieties developed many localized names during propagation and cultivation. For example, what everyone often calls Tim variety is called Tim Tim or Bor Bor in Indonesia.

Faced with such a diverse range of green bean varieties, it is difficult for Indonesia to name coffee by a single species. In addition, because of historically famous producing regions, coffee from Java Island is usually called Java coffee, Arabica coffee from North Sumatra is called Mandheling coffee, and the best-known coffee from Sulawesi Island is Toraja coffee, a name derived from the ethnic group on the island known for growing coffee. There is also Kopi Luwak, named for its special processing method.

The Golden Mandheling coffee beans produced by PWN are sourced from the Gayo Mountain region of Aceh Province, at the northernmost tip of Sumatra Island. The variety is Ateng, which is the local name obtained after Catimor was introduced to Aceh for cultivation; Ateng is the abbreviation for the central Aceh region.

Indonesia’s complex green bean grading standards

Such a complex green bean variety system has also given rise to a unique set of coffee grading standards in Indonesia. Its grading logic is roughly based mainly on the number of defective beans, with coffee bean size as a secondary reference.

According to defect rate, Indonesian green beans are divided into six levels, G1 to G6.

Coffee bean size labeling

Some higher-quality Indonesian coffees also indicate the coffee screen size; for example, Golden Mandheling will mark 17 screen or 18 screen.

Sorting frequency

In addition to the above grading standards, some specialty-grade Indonesian coffees are also manually sorted, shown on the label as Double Picked or Triple Picked. This is because Indonesia mostly uses the wet-hulled method to process green beans, during which defective beans are easily produced. The more times hand sorting is performed, the more guaranteed the coffee quality is.

In December 2020, FrontStreet Coffee received a batch of Golden Mandheling coffee from the new crop season of October that year. The packaging bag has the basic information of the coffee beans printed on it. Let’s take a look together.

PWN: This is the logo of Pawani Company

GOLDEN MANDHELING: Golden Mandheling

TRIPLE PICKED: Triple Picked, reflecting its exceptional quality

COFFEE ARABICA: Arabica coffee, referring to the coffee bean variety. PWN had previously been selecting coffee beans in the Lintong region (the variety was Typica), but in recent years coffee farmers in the Lintong region have grafted trees in pursuit of yield and profit, causing a sharp decline in quality. Therefore, PWN has now shifted its producing region to the Gayo Mountains of Aceh, with the variety being Ateng.

GRADE 1: That is, G1, the highest level in Indonesia’s green bean grading system, with fewer than 11 total defects in the green beans.

PROD.OF INDONESIA: That is, product of Indonesia, produced in Indonesia

30 KGS NET: 20 kilograms including the jute bag

EXP: 10.2024: Shelf life until October 2024, which also exactly confirms that this batch is beans from the October 2020 crop season.

FrontStreet Coffee roasting analysis

Golden Mandheling has a high-quality herbal aroma, a stronger caramel sweetness, and a relatively steady and elegant fruity acidity. It has a rich sweetness, high body, and a wild spice flavor. Generally, Lintong Mandheling is best discharged after the second crack, as this can effectively reduce off-flavors, but Golden Mandheling can show very good clarity and sweetness when discharged before the second crack, giving a broader space for roasting interpretation.

When the drum temperature rises to 200°C, charge the beans, set the damper to 3, and after 1 minute adjust the heat to 160°C while keeping the damper unchanged. Roast until 5 minutes 40 seconds, at 148°C, when the bean surface turns yellow, the grassy smell completely disappears, and dehydration is complete. Adjust the heat to 140 and the damper to 4;

At 9 minutes 40 seconds, ugly wrinkles and dark patches appear on the bean surface, and the toast aroma clearly turns into coffee aroma. This can be defined as the prelude to first crack. At this time, listen carefully for the sound of the first crack. First crack begins at 9 minutes 54 seconds. Reduce the heat to 60 and open the damper fully (adjust the heat very carefully; do not reduce it so much that there is no crackling sound). Discharge at 204.5°C.

FrontStreet Coffee brewing sharing

This brewing highlights the rich, clean, and aromatic characteristics of Golden Mandheling, using a KONO dripper for brewing (this dripper was invented to imitate the strong coffee produced by flannel). For medium-dark roasted coffee, choose a medium-coarse grind (57% passing a No. 20 standard sieve). Use a coffee-to-water ratio of 1:13, with 20 grams of coffee powder; lowering the coffee-to-water ratio makes the coffee taste richer. Use a water temperature of 87°C.

Brewing process: Slowly pour in the coffee powder, trying to keep it as level as possible while pouring, and avoid shaking the dripper (because shaking will reduce the spacing between coffee particles, which is not conducive to degassing during blooming). In the first stage, pour 40g of water in a small circle in the center and bloom for 30 seconds; the coffee bed will slowly expand and puff up into a “hamburger.”

In the second stage, pour 120g in circles from the center outward, keeping the pouring height as close to the coffee bed as possible and moving slowly to avoid excessive agitation. In the final stage, pour 100g, and finish extraction when all the coffee liquid in the dripper has flowed into the server. The extraction time is 2 minutes.

Flavor description of Golden Mandheling: nuts, chocolate, spices, herbs, caramel. Golden Mandheling tastes cleaner than Lintong Mandheling. The original herbal, earthy, and woody notes of Mandheling are almost gone, but the caramel sweetness is stronger, and the fruity acidity is also brighter and more elegant.

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