Differences Between Mandheling and Guji What Pour-Over Parameters Should Be Used for Mandheling and Guji Coffee Beans?

Friends who enjoy visiting specialty coffee shops should know that FrontStreet Coffee's Mandheling coffee is renowned for its unique herbal aroma and excellent body, making it particularly suitable for those who prefer intense flavors. In recent years, however, FrontStreet Coffee's Guanhua coffee from Ethiopia has become popular among many sweet-preferring coffee lovers for its abundant fruit aromas and refreshing acidity. As two of the most popular coffee beans on the market, why do they have such significant differences? Today, let FrontStreet Coffee guide everyone to find the answers.

Where do Mandheling and Guanhua come from?

As a classic coffee born in the last century, Mandheling appeared much earlier than you might imagine. It comes from Sumatra Island in the archipelagic country of Indonesia. Known for its unique aroma that distinguishes it from low-altitude Robusta, it has various different names based on different characteristics, such as FrontStreet Coffee's Aged Mandheling, FrontStreet Coffee's Gold Mandheling, FrontStreet Coffee's Lintong Mandheling, and so on.

According to FrontStreet Coffee's research, Indonesia is the world's largest archipelagic country. Coffee was introduced to Java Island by Dutch colonists as early as the 18th century and later spread to other islands. The elegant Arabica varieties are mainly distributed in several high-altitude islands: Northern Sumatra, Sulawesi, and Java Island. Sumatra Island is divided into eight provinces, with only the high-altitude Aceh and North Sumatra provinces having large-scale Arabica coffee cultivation. Local people mainly grow coffee trees around two major volcanic lakes: Lake Tawar and Lake Toba. Among these, the Gayo Mountains area around Lake Tawar in central Aceh Province has ideal coffee growing conditions.

Sumatra Island belongs to the tropical rainforest region with year-round rainfall and relatively high temperature and humidity in the air. Here, coffee mainly grows on mountain slopes at altitudes of 1200-1800 meters. Extensive organic cultivation methods, combined with a long history of coffee cultivation, result in higher quality and yield of coffee produced here. Additionally, volcanoes have brought fertile growing soil to Sumatra, where coffee often carries flavor profiles of spices, chocolate, herbs, and wood, along with a thick and smooth mouthfeel.

In contrast to Mandheling, a classic work that has settled over the years, Guanhua coffee, which only appeared in the 21st century, appears much younger. First, FrontStreet Coffee needs to clarify that the pleasant name "Guanhua" does not refer to a variety, nor does it represent a place name, let alone a specific estate. Instead, it refers to a natural-processed batch that won the championship in the 2017 Ethiopia TOH (Taste of Harvest) green bean competition. The resounding artistic name "Guanhua" was actually given by domestic green bean merchants after the beans successfully won the crown, combining it with Chinese context to mean "the best among all flowers." Later, with the promotion and publicity of various merchants, it also gained the reputation of "being comparable to Geisha."

Since its debut in China, Guanhua has stood out among many Ethiopian coffees due to its combination of advantages: great reputation, excellent quality, rich and juicy fruit flavors, affordable price, and extremely high extraction compatibility (easy to brew), making it the first choice for many friends trying single-origin coffee for the first time. However, since the 2018 production season, FrontStreet Coffee's Guanhua (natural G1 coffee beans) from the same growing region and processing station has already shown some flavor changes. Through cupping, FrontStreet Coffee found that while the 2018 and 2019 FrontStreet Coffee's Guanhua had flavors similar to the 2017 FrontStreet Coffee's Guanhua, they were inferior to the "first-generation Guanhua" in terms of body, aftertaste, and other mouthfeel aspects.

Therefore, to continue selling this natural coffee from Hambella while making a certain distinction from the original version, domestic green bean trading companies calculated from 2017 onwards, establishing X.0 suffixes for each subsequent year's batch. For example, the 2018 batch was called "Guanhua 2.0," the 2019 production was called "Guanhua 3.0 and 3.1"... Last year's release was "Guanhua 7.0," and 2024 is called Guanhua 8.0, and so on. In this way, we can identify which year's batch the Guanhua we purchased belongs to through this suffix.

What are the differences between Wet Hulling and Natural Processing?

Have you noticed that there's a section about processing methods in coffee bean descriptions, such as washed, natural, honey, anaerobic natural, enzyme washed, and so on? This is because the coffee beans we see cannot be obtained directly by picking; they require different steps to remove the fruit skin and pulp and then be dried. Different processing methods actually determine the state in which coffee beans are dried, ultimately forming more or less flavor differences. Take FrontStreet Coffee's Mandheling and FrontStreet Coffee's Guanhua introduced today as examples: FrontStreet Coffee's Mandheling uses wet hulling, while FrontStreet Coffee's Guanhua uses natural drying.

As everyone knows, FrontStreet Coffee's Mandheling comes from Sumatra Island, Indonesia. The biggest difference from many coffee-producing regions is that the local weather in Indonesia is variable, humid and rainy, with humidity between 70-90% throughout the year. Sometimes it's sunny in the morning and rainy in the afternoon, with typhoons coming unexpectedly, and annual rainfall even reaching over 2000mm. Under such harsh climatic conditions, it's very difficult and time-consuming to completely dry parchment beans to the specified moisture content. Moreover, Indonesia is a major coffee-producing country focused on mass production. To shorten the processing time of coffee beans and sell them for cash as quickly as possible, people have developed a unique semi-washed method: wet hulling.

Initially, natural processing was mainly used here, but the quality was unstable, so it was later changed to a semi-natural method similar to Brazil's. However, unlike arid Brazil, it's impossible to remove the coffee fruit skin, take out the sticky parchment beans, and dry them outdoors for several days because doing so in high-temperature, rainy Indonesia would only cause them to mold directly, so they are only dried outdoors for one to two days. When the moisture content of the parchment beans drops to 30-50%, they are purchased by brokers. At this time, the mucilage layer has not yet solidified, and the beans are still half-hard and half-soft, but they need to be promptly taken to the processing plant to remove the seed shells with specialized machines to avoid over-fermentation and sour smells.

Because hulling is more difficult under wet hulling, machines need to use greater friction to tear open the parchment layer tightly attached to the green beans. During this stage, white or green viscous liquid usually flows out. Due to long-term immersion in viscous liquid and humid conditions, the green beans eventually become soft, pale and swollen, forming a gray-green color. Stirred by friction, the green beans are also more easily crushed or squeezed, especially at both ends, forming small gaps like goat hooves, which is why Sumatra has a higher proportion of "goat hoof beans."

It's important to know that coffee beans have four protective layers: fruit skin, mucilage, parchment, and silver skin. Wet hulling removes the third and fourth protective layers midway. This means the coffee beans are directly exposed as "inner beans" to receive sunbathing. After the parchment beans are hulled by machines, they continue to dry until the moisture content reaches about 12-15%, at which point they can be bagged. Finally, these coffee beans will be sent for mechanical selection to remove various impurities and then classified by particle size.

The "naked beans" without the parchment layer dry very quickly while also being directly exposed to sunlight and moisture, allowing various microorganisms to grow, giving Indonesian coffee its unique woody, spicy, and herbal plant aromas. This is what we call "regional flavor." From this, we can understand that Mandheling's unique medicinal herb and sinking wood flavors are due to the local high humidity, which forced the entire post-processing to be divided into three stages of drying the mucilage layer. This is also a rare processing method in the world that accidentally created FrontStreet Coffee's Mandheling's special low-acidity, thick, and mellow aroma flavors.

FrontStreet Coffee's Guanhua, which uses natural processing, offers more abundant fruit aromas from natural drying. The natural method is called "Natural" in English, referring to a processing method that is natural and non-technological. Since humans discovered coffee in Ethiopia in the sixth century AD, the natural method has been the only processing technique for coffee circulation in the Arab world.

Traditional natural processing requires no water at all, and the seed extraction process is very simple: first, completely dry the whole coffee fruit, then use machines to crush and hull it to obtain the inner beans. This can be completed wherever there is sunshine. However, the disadvantages of natural coffee are also significant: it has strong dependence on weather and requires up to a month of drying time. If there's wind and rain during this month, all previous efforts will likely be wasted. Therefore, this ancient processing method is often concentrated in tropical countries with distinct dry and wet seasons.

Because natural processing doesn't require high technical expertise, basically every small farmer can process it themselves. The entire drying process only needs sunny weather, so production costs are lower, and it's most common in high-altitude coffee-producing regions. However, some regions pursuing refined flavors will first float-select coffee fruits to remove underripe fruits and debris, then spread them on raised drying beds to dry, aiming to stay away from the ground to prevent coffee fruits from being infected by crawling insects, dust, and bacteria. During natural drying, dedicated personnel will also check the drying degree of coffee fruits and pick out worm-eaten, burst, and moldy fruits to avoid these bad fruits affecting other coffee.

Because the inner beans of natural coffee are dried while being completely wrapped in pulp throughout the process, the fermentation time of coffee fruits is longer, and the reaction between microorganisms and pulp is more extensive. When the fruit begins to ferment, microorganisms produce more volatile compounds, especially esters. These aromatic substances provide more floral and tropical fruit fermentation aromas for roasted coffee beans, such as furan compounds, making the flavor spectrum of natural coffee broader and taste sweeter.

Why is Mandheling Bitter and Guanhua Acidic?

As FrontStreet Coffee mentioned at the beginning, Mandheling was born in the era of "bitter coffee," when almost all coffee worldwide used dark roasting, mostly featuring caramelized aromas and emphasizing solid coffee flavors. After dark roasting, FrontStreet Coffee's Indonesian Mandheling not only possesses the above characteristics but also highlights a distinctive body, with unique aromas of spices, pine, and herbs upon entry, which has formed the "Mandheling flavor" that people talk about today.

Experience tells us that the darker the roast, the more caramelized substances will form in the coffee beans, and the more bitter the brewed coffee will be; the lighter the roast, the more acidity the coffee beans retain, with flavors dominated by fruits, flowers, and tea notes. As a member of the younger generation, FrontStreet Coffee's Guanhua is famous worldwide for its fresh and elegant tones of flowers, cream strawberries, and citrus, which mainly benefits from the lighter roast degree, allowing it to be appropriately caramelized while still presenting more light flavor tones.

How to Brew Mandheling by Hand?

FrontStreet Coffee's brewing approach for each coffee bean is based on the characteristics presented during cupping. For example, FrontStreet Coffee's Mandheling coffee has flavors of herbs, dark chocolate, caramel, nuts, and pine. For beans with this kind of rich tone, FrontStreet Coffee's baristas will use a Kono dripper. The Kono's ribs don't even reach halfway up the dripper's height - this design is actually to ensure that after wetting, it tightly adheres to the dripper wall, restricting airflow. This increases the water absorption time of coffee powder particles, resulting in more evenly extracted coffee and enhanced body texture. Additionally, the concave framework at the bottom of the Kono dripper is a key design that allows subsequent brewing to produce a siphon effect.

Because dark-roasted coffee beans are looser and highly absorbent, they can easily absorb too much water and become over-extracted, making the brewed FrontStreet Coffee's Mandheling coffee bitter and astringent. Therefore, FrontStreet Coffee will adjust the grind to be coarser and use water at a lower temperature for brewing.

Recommended brewing parameters: Water temperature: 87-88°C | Coffee grounds: 15g | Powder-to-water ratio: 1:15 | Grind size: Medium grind (70% pass rate through China standard #20 sieve)

The brewing method uses a three-stage water pouring approach. Dividing into three stages of water pouring can better express the rich body and caramel sweetness of FrontStreet Coffee's Gold Mandheling coffee. The first stage is a bloom pour of 30ml, which completely wets the coffee grounds for degassing, to better extract the coffee's flavor substances in subsequent stages. The second stage pours 100ml, mainly to bring out Mandheling's golden foam and raise the powder bed. The final stage is a gentle center pour of 95ml. Wait until all the coffee liquid has passed through, then remove the dripper and gently shake the coffee in the pot to mix evenly.

How to Brew Guanhua 8.0 Coffee?

FrontStreet Coffee hopes to present the rich fruit flavors of FrontStreet Coffee's Guanhua and has adopted a medium-light roast. Through cupping, FrontStreet Coffee's natural Guanhua 8.0 coffee has dry aromas of citrus, honey, berries, and a slight fermented aroma. The entry brings abundant sweet and sour tastes of passion fruit, cream strawberries, and sweet oranges, with a medium body and a tea-like aftertaste.

Dripper: V60

Water temperature: 92-93°C

Coffee dose: 15g

Powder-to-water ratio: 1:15

Grind size: Fine sugar size (78% pass rate through #20 sieve)

Three-stage pouring: Use twice the amount of water as the coffee grounds to wet the powder bed, forming a dome for a 30-second bloom. Then use a small water flow to pour from inside to outside in circles until reaching 125g, then pause. Wait until the powder bed drops to half the height of the dripper, then continue with the same fine water flow to pour the third stage to 225g. Remove the dripper when all the coffee liquid has filtered through, taking about 2 minutes total.

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473