Why is Japanese Dark Roast Coffee So Bitter? How to Brew Sweetness from Dark Roast Coffee Beans?

If you were born before the year 2000, your first impression of black coffee was probably its monotonous bitterness, and the only non-bitter coffee option was Nestlé's 2-in-1 instant coffee.

This uniform bitterness in coffee actually stems from the deeply roasted coffee beans that were popular in the last century, completely different from the light-roasted beans with floral and fruity notes that are favored today. Why would anyone like such bitter coffee?

If you're fortunate enough to meet an older gentleman who enjoys this type of bitter coffee, try to seek answers from him.

"Is this coffee bitter?"

"Bitter!"

"Why do you like this kind of bitter coffee?"

"I don't know, maybe I'm used to drinking it. I remember the first time, I was attracted by that aroma. When I drank it, I found it very bitter, but that bitterness was comfortable, hard to describe... Over time, I got used to it."

What this gentleman said actually explains why one group of people loves strong, bitter black coffee—it's a memory of the era. Back then, the taste of coffee was defined as "coffee-flavored"—bitter, smooth, and rich. People who liked this taste naturally became coffee fans, while those who didn't like coffee naturally wouldn't have anything to do with it.

Another reason is that coffee was regarded as a functional beverage for refreshing the mind and boosting energy. In many situations, people needed it and relied on it. To achieve its refreshing effect, sacrificing a bit of taste was acceptable.

The Appeal of Dark Roast Coffee

Besides historical reasons, what FrontStreet Coffee wants to discuss next is what appealing charms dark roast coffee possesses.

Coffee Aroma

The enticing aroma of coffee initially refers to the fragrance emitted by this rich, bitter dark roast black coffee. These aromas are complex combinations of nuts, caramel, roasted chestnuts, cream, and spices. People find it hard to resist the temptation of this aroma. Many friends slowly fall in love with coffee starting from its aroma.

Rich Body

Dark roast coffee offers a mouthfeel experience that light roast coffee cannot compare to. Today, many friends still love Blue Mountain and Mandheling coffee, largely because they provide a richness and volume that other coffees lack, allowing your mouth and tongue to experience the incredible smoothness and fullness of the coffee.

Sweetness

That's right—even dark roast coffee has its unique sweetness, which is bitterness with underlying sweetness. Taking the dark roasted Mandheling coffee as an example, many people can easily perceive the nutty bitterness and cocoa bitterness in the coffee. If you taste it more carefully, you can detect the sweetness of caramel and maltose, which is what the gentleman referred to as "comfortable bitterness."

After swallowing the coffee, the bitterness dissipates, giving way to sweetness. "Aftertaste" is another important reason why people like to drink bitter coffee, and it's also a characteristic that's difficult to replicate with light roast coffee.

Brewing Approach for Sweet Dark Roast Coffee

Friends who dislike sourness usually prioritize darker roasted beans when buying coffee beans because they typically present roasted aromas like nuts, dark chocolate, almonds, and melon seeds, with minimal acidity, highlighting sweet notes of cocoa, caramel, maple syrup, and other flavors.

However, since medium-dark to dark roasted beans undergo longer and higher heat exposure, their texture is very loose, and the caramelization reaction is more extensive than in light roast coffee. Therefore, under the same parameters, bitterness in the later stages is more easily released. Once parameters aren't well-controlled, the roasted bitterness can easily dominate, causing the sweetness to be masked, and the resulting coffee can be shockingly bitter, with astringency lingering in the throat for a long time. Therefore, brewing dark roast coffee to highlight its sweetness is not only one of the main practices for many newcomers to improve their brewing skills but also a key for experienced brewers to master the balance of coffee.

To avoid extracting excessive undesirable flavors while retaining the mellow sweetness, FrontStreet Coffee uses a slow-flow Kono dripper, coarse sugar-like grind size, and low water temperature (88°C), while gently pouring in small circles, and using a 1:15 coffee-to-water ratio to rinse the coffee grounds, with the time controlled around 2 minutes. Below, FrontStreet Coffee demonstrates specific operations using the store's dark roast representative—Golden Mandheling coffee beans—as the extraction subject.

Brewing Sweetness from Dark Roast Golden Mandheling

Golden Mandheling coffee has complex aromas. To experience the best flavor and texture, FrontStreet Coffee recommends using freshly roasted coffee beans for brewing. Coffee beans reach their optimal flavor period 4-7 days after roasting. Beyond this period (about a month and a half), the aroma gradually diminishes and develops woody defect flavors. FrontStreet Coffee believes that the freshness of coffee beans is particularly important, so the shipped coffee beans are freshly roasted within 5 days. Adding the time for logistics and shipping, you can start enjoying them upon receipt.

FrontStreet Coffee's brewing approach for each coffee bean is based on the characteristics presented during cupping. For example, Golden Mandheling coffee has flavors of herbs, dark chocolate, caramel, nuts, and pine. For this type of mellow-toned bean, FrontStreet Coffee's baristas will use a Kono dripper. The Kono's ribs don't even reach halfway up the dripper's height—a design actually intended to ensure that after wetting, the filter paper tightly adheres to the dripper wall, restricting airflow. This increases the water absorption time of the coffee grounds, resulting in more uniform overall extraction and enhanced rich body. Additionally, the concave framework at the bottom of the Kono dripper is a key design that allows siphoning effects during subsequent brewing.

Since dark roasted coffee beans are looser and have strong water absorption, they easily lead to over-extraction from absorbing too much water, resulting in Mandheling coffee that is both bitter and astringent. Therefore, FrontStreet Coffee adjusts the grind size to be coarser and uses water at a slightly lower temperature for brewing.

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

The brewing method uses a three-stage pouring approach, which can better express the rich body and caramel sweetness of Golden Mandheling coffee. The first stage bloom: pour 30ml of water to fully wet the coffee grounds for degassing, facilitating better extraction of coffee flavor substances in subsequent stages. The second stage: pour 100ml, which mainly brings out the golden foam of Mandheling and raises the coffee bed. The final stage: gently pour 95ml at the center. Wait for all the coffee liquid to pass through, then remove the dripper and gently stir the coffee in the pot.

Hand-poured PWN Golden Mandheling coffee tastes very rich, emitting spicy and herbal aromas, presenting an overall solid rich body, with caramel sweetness and flavors of chocolate and nuts.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473