Why Does Pour-Over Black Coffee Taste Bitter? How to Perfectly Brew Dark Roast Coffee Beans?

Nowadays, when ordering pour-over coffee at a café, you might find that eight out of ten bean varieties have acidic flavors. However, there are still many "ascetic" coffee enthusiasts who exclusively prefer bitter coffee. What exactly is the charm of bitter coffee? Why, in an era where acidic coffee is widely sought after, do so many coffee connoisseurs remain devoted to bitter coffee?

Where Does Coffee's Bitterness Come From?

The acidity and bitterness of coffee are actually determined by the degree of roasting. In coffee roasting, there's a term called "first crack." At this point, the coffee beans have absorbed heat to a level where they can no longer continue storing energy, so they release heat through cracking (with audible sounds). Roasters use this as an indicator to judge the degree of coffee bean roasting.

If the beans are removed right at the beginning of the "first crack," the coffee will be very acidic. If we don't remove them after the "first crack" begins and continue roasting until the crackling sounds become dense, the coffee will have a sweet-acidic balance. If we still don't remove them and wait until the cracking sounds stop completely, then the coffee removed afterward will begin to develop bitterness, with the later removal resulting in stronger bitterness.

As the roasting level deepens, the acidic substances within the coffee beans are eliminated, ultimately presenting flavors that lean toward bitterness, such as nuts and dark chocolate. Therefore, compared to light-roasted beans, dark-roasted beans have significant gaps in flavor complexity and variation. However, dark-roasted bitter coffee still possesses its own unique charm that cannot be experienced when drinking light-roasted coffee.

The Unique Charm of Dark-Roasted Bitter Coffee

Coffee Aroma:

Dark-roasted coffee also has captivating aromas. Unlike the floral and fruity acidic notes of light-roasted beans, these aromas are complex scents of nuts, caramel, toasted bread, and chocolate. Many coffee connoisseurs specifically pursue this type of nutty, bitter fragrance.

Rich Mouthfeel:

Dark-roasted coffee offers a mouthfeel experience that light-roasted coffee cannot match. Many coffee enthusiasts who favor Blue Mountain or Mandheling coffee are largely drawn to dark-roasted coffee for its richer mouthfeel, allowing them to experience the full-bodied, smooth sensation of coffee in their mouth while perceiving the flavors.

Sweet Aftertaste:

Yes, even dark-roasted bitter coffee can have that unique sweetness—what we often call "sweetness within bitterness." A properly extracted dark-roasted bitter coffee, while predominantly bitter upon entry, may reveal sweet flavors like caramel or malt sugar upon careful tasting. After swallowing, the bitterness gives way to sweetness, with pleasant aromas lingering in the mouth for a long time—another characteristic that light-roasted coffee struggles to replicate.

Of course, the unique charms of bitter coffee mentioned above need to be built on the premise that you brew it well. If you don't want to create an unforgettable bitterness, FrontStreet Coffee suggests choosing conservative parameters when brewing.

FrontStreet Coffee takes brewing Golden Mandheling as an example: water temperature at 86-88°C, grinding at 70% pass-through rate through a #20 sieve (EK43s setting 11), using a Kono dripper, with a coffee-to-water ratio of 1:15, and extraction time around two minutes.

Compared to brewing light-roasted beans, using lower water temperature for dark-roasted beans and adjusting the grind to be coarser can make the coffee's bitterness milder and avoid extracting undesirable flavors. In terms of dripper selection, using slower-flow drippers like Kono or Kalita can more easily create a rich mouthfeel and mellow flavors.

When brewing dark-roasted beans, the bloom must ensure sufficient blooming, which can be judged in two aspects. First, confirm that all coffee grounds are moistened and that some coffee liquid is released from the bottom. Second, the coffee grounds layer should stabilize after expansion and no longer release gas.

Adjustments are also needed in water pouring. It's recommended to slow down the pouring pace as much as possible, and the water flow can be adjusted to be finer accordingly to avoid excessive agitation of the grounds layer, which would extract more bitter and undesirable flavors. Pouring in small circles will result in slightly thicker grounds walls compared to light-roasted coffee.

If you've read this far and are becoming interested in dark-roasted bitter coffee, why not give it a try?

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FrontStreet Coffee

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