Introduction to Aged Sumatra Mandheling Coffee Beans - Can Aged Coffee Be Drunk & How to Drink Aged Coffee

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Mandheling coffee from the Sumatra mountains is world-renowned for its rich texture. In contrast to the wine-like flavors of East African coffees, Indonesian and New Guinea beans showcase a different character: a viscous texture, acidity buried deep within complex flavors, dark and intense herbal or wild mushroom notes, and a lingering sweet aftertaste that resonates in the throat for days. FrontStreet Coffee offers four varieties of Mandheling coffee: for those wanting to experience the distinctive flavors of the Indonesian region, choose the Lintong region Mandheling as your daily brew; for those preferring a clean, mellow cup with sweet aftertaste, select Golden Mandheling; for those seeking prominent aromatics, try Tiger Mandheling; and for those desiring even more richness, sample the Aged Mandheling coffee beans. In this article, FrontStreet Coffee will elaborate on what aged Mandheling coffee beans are.

Sumatra Coffee Beans

90% of coffee beans grown in Indonesia are of the Robusta variety, with the remaining 10% being Arabica coffee beans mainly produced from the Lintong region of Lake Toba in Sumatra and the Gayo Mountains in Aceh. Indonesian growing regions typically have two harvest seasons: the main harvest season occurs around September-October, while the fly harvest season is in May-June.

Lake Toba Lintong Region

Lake Toba is located north of Medan, the capital of Sumatra Island, and is a high-altitude freshwater lake. The average elevation is about 900 meters. The lake is diamond-shaped, 100 kilometers long and 30 kilometers wide, covering an area of 1,130 square kilometers, with an average elevation of 1100-1600 meters, making it the world's largest volcanic lake. The commonly referred-to Mandheling consists of Typica or its variety coffee beans grown in the mountainous areas surrounding Lake Toba, with Lintong being the most famous Mandheling coffee-producing region in the Lake Toba area. Lintong Mandheling is essentially the regular version of Mandheling.

Aceh Gayo Mountain Region

The Gayo Mountain region is located in Aceh Province on the northern part of Sumatra Island. Coffee in the Gayo Mountain region is grown on the slopes surrounding the town of Takegon and Lake Tawar. The growing altitude averages between 1,110 and 1,600 meters in the production area. Coffee is cultivated by small tenant farmers under shade trees, using the wet-hulled processing method to express unique flavors and deep, lively richness. Aceh, located at the northernmost tip of Sumatra Island, is a fascinating and complex place. Due to long-term political instability, Aceh is not a region typically visited by ordinary people.

Wet-Hulled Processing Method

Due to the local weather being predominantly rainy with constant typhoons, it's impossible to achieve the good weather required for sun-drying, and the local economy isn't strong enough to use the more expensive washed processing method. For these various reasons, the uniquely local wet-hulled method was developed (wet-hulled processing involves sun-drying the beans with parchment for 2-3 days during the regular washed process until reaching 20-24% moisture content, then hulling the parchment). The extremely fast speed of wet-hulled processing also results in a higher defect rate in Mandheling beans, which Golden Mandheling effectively avoids.

Because the semi-hard, semi-soft moist green beans are easily bruised when the mucilage parchment layer is removed, the beans crack open like goat hooves, commonly known as "goat hoof beans." These are not defective beans but can be considered a very distinctive characteristic of Mandheling. FrontStreet Coffee's Golden Mandheling specifications are 19 screen or larger, with fewer than 3 defective beans (in a 300g green bean sample), belonging to the highest G1 grade, with a dark green color and uniform flat bean shape. Through cupping multiple wet-hulled processed coffee beans, FrontStreet Coffee found they have acidic and high body characteristics.

What is Aged Sumatra Coffee?

"Aged Sumatra" is a specially processed type of bean. Aged Mandheling actually has a long history in Indonesia because early shipping wasn't as developed, and transporting coffee from Indonesia to other countries required considerable time. Over time, the originally moisture-rich fresh coffee beans gradually dried, and the exposure to sea winds added a rather special flavor.

Due to advancements in modern shipping greatly reducing transport time, this type of special-flavored coffee has become a specially processed coffee bean. Aged Sumatra coffee beans don't simply mean letting green beans sit for a long time to become aged—this is not acceptable! Because green beans left for too long will still spoil, turning from fresh green to white, then to yellow, becoming tasteless, and even growing insects. Like aged wines, green beans must undergo proper processing and long-term storage before they can be called true "aged coffee."

FrontStreet Coffee's Aged Mandheling

Region: Sumatra

Altitude: 1500 meters

Varieties: Catuai, Typica

Processing: Wet-hulled

How are Coffee Beans Aged?

In recent years, aging processing has become quite mature. Coffee beans first undergo wet-hulled processing (wet-hulled processing involves sun-drying beans with parchment for 2-3 days during regular washed processing until reaching 20-24% moisture content, then hulling the parchment to dry the green beans to 12-13% moisture content), then they are sealed in warehouses. The warehouse environment must be cool and ventilated, and beans must be turned regularly to prevent mold and spoilage, stored for 2-3 years. During this period, the coffee beans' acidity gradually diminishes and converts to sugars, while the color becomes deeper, mostly yellowish-brown or dark brown, which is highly recognizable. Through cupping, FrontStreet Coffee believes that aged Mandheling lacks the wildness of traditional Mandheling but gains more richness and delicacy, with a mature and steady feeling and lower acidity.

FrontStreet Coffee's Roasting Recommendations for Aged Mandheling Coffee Beans

FrontStreet Coffee suggests paying attention when roasting coffee because Mandheling green beans have high density and aged beans have low moisture content, so heat adjustments at each stage must be particularly careful to avoid scorching the oils on the bean surface. Since aged Mandheling has low and soft acidity, FrontStreet Coffee recommends roasting to medium-dark to increase its purity and smooth mouthfeel.

FrontStreet Coffee's roaster used a Yangjia 800N with a batch size of 480g. Heat to 200°C before dropping beans, with damper set to 3. After 1 minute, adjust heat to 160°C, keeping damper unchanged. Roast until 5'35'', temperature reaches 146°C, bean surface turns yellow, grassy aroma completely disappears, dehydration is complete, adjust heat to 140°C, damper to 4. At 8'10", ugly wrinkles and black spots appear on the bean surface, toast aroma clearly transitions to coffee aroma, which can be defined as the prelude to first crack. At this point, listen carefully for the sound of first crack. At 9'30", first crack begins, reduce heat to 80°C, set damper to 5, and drop at 197.5°C.

FrontStreet Coffee's Cupping Report for Aged Mandheling Coffee Beans

FrontStreet Coffee conducts cupping within 8-24 hours after roasting sample coffee beans. FrontStreet Coffee's baristas typically use 200ml ceramic cupping bowls marked with 150ml and 200ml measurement lines, following SCAA standards. The water TDS is around 150ppm—too low TDS can easily cause over-extraction, while too high TDS can affect mouthfeel and cause under-extraction. Cupping water temperature is 94°C. Grind size is controlled to 70-75% pass-through rate through a #20 standard sieve (0.85mm). Ratio: 11 grams of coffee grounds to 200ml of hot water, i.e., 1:18.18, so the extraction concentration falls within the 1.15%-1.35% golden cup range. Steeping time is 4 minutes.

Dry Aroma: Herbal

Wet Aroma: Chocolate

Flavor: Aged Pu-erh tea, herbal, caramel, chocolate, low acidity

FrontStreet Coffee's Brewing Recommendations for Aged Coffee

Dripper: Kono

Recommended Water Temperature: 87-88°C

Grind Size: Fuji Royal grinder 4.5 (coarse sugar size)

Coffee-to-Water Ratio: 1:15

Dose: 15 grams

FrontStreet Coffee's Brewing Technique:

Use 30g of water for a 30-second bloom. When pouring with a small stream in a circular motion to 125g, create a pause. When the water level drops and is about to expose the coffee bed, continue pouring to 225g and stop pouring. When the water level drops again and is about to expose the coffee bed, remove the dripper. (Timing starts from the bloom) Extraction time is 2'00''.

Brewing Flavor:

Aromas of pine, malt, and caramel immediately emerge. The mouthfeel lacks the wildness of traditional Mandheling but gains more richness and delicacy, with a mature and steady feeling and low acidity. The cup reveals flavors of aged Pu-erh tea, caramel, herbs, and chocolate, with abundant sweetness.

For more specialty coffee knowledge, please follow the WeChat Official Account: FrontStreet Coffee

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473