How the Roasting Process Shapes Dark Roast in Specialty Coffee

Dark roast remains a legitimate style within specialty coffee even though the third wave favors light and medium roasts to express terroir. Dark roasting develops bittersweet, cocoa and caramel notes that many drinkers prefer, and the SCA scale recognizes the profile. It is judged harshly because flaws in green coffee and in the roasting process are harder to hide at high development.

Japan's kissaten tradition built its identity on this bittersweet style. Dark roasting also reduces some compounds while forming others, including niacin and NMP, which changes the nutritional profile of the cup. Because the roast leaves less margin for error, a well-executed dark roast demands more control over extraction methods, grind and water temperature than a light one.

In the third wave of specialty coffee, light-medium roasting has become almost synonymous with the expression of "terroir," so much so that many enthusiasts frown the moment they see dark-roasted beans, even equating them with "Chinese herbal medicine taste" or "inferior beans." But is dark roasting truly incompatible with specialty coffee? What is the reason for its existence? From the SCA system to the bittersweet aesthetics of old Japanese kissaten, from differences in extraction methods to niacin and NMP on the health level, this article will dissect the rationale behind dark roasting from a professional perspective and explain why a good cup of dark-roasted coffee is often harder to find than a light roast. Front Street Coffee will also share the key principles of dark roast brewing, guiding you to rediscover this underrated roasting style.

Walk into a café today and the words "specialty coffee" are practically everywhere. But what exactly do they mean? Why is it that in the countless self-roasting shops that have sprung up, over ninety percent of owners tend to use light-medium roasts to present the flavors of a green bean?

Anyone who follows coffee news even casually has likely heard the term "third wave of specialty coffee." Looking back at history, the first wave brought instant coffee into daily life, making coffee convenient to drink; the second wave pushed espresso to the masses, raising quality and turning coffee from a daily beverage into a product with an indulgent quality; the third wave, however, is concerned with far more than that.

Natural process, washed process, honey process, low-pollution processing methods, origin cultivation, micro-lots—the third wave of specialty coffee has many demands, but at its core, the one thing it cares about most is "terroir."

[Terroir] This concept is borrowed from the world of wine; it holds that any subtle difference in conditions at the place of origin can change the final flavor of a bean.

In the past, we were used to distinguishing flavors by Ethiopia, Blue Mountain, Kenya. Now, it is not enough to just say Ethiopia—we have to break it down further: the large region Yirgacheffe, the smaller region Kochere, and even down to the specific washing station Bolife, the processing method natural, the grade G1, the altitude 1800M–2300M, the variety Ethiopian heirloom, and the story behind Operation Cherry Red...

The reason labels keep multiplying is to let consumers use "knowledge" to approach a "flavor" they have not yet tasted. Put plainly, it helps people find or discover the beans and tastes they prefer more quickly. And precisely because the pursuit is such an original and delicate expression of flavor, the "light roast" level has risen to popularity.

In the light-medium roast range, the coffee's own "terroir" is most easily expressed. The bright, lively acidity and fruity notes are typically the direction this roast level aims to convey, and combined with "black" coffee extraction methods such as pour-over, siphon, and AeroPress, it constitutes the approach most aligned with the core philosophy of third wave specialty coffee.

Light-roasted coffee also retains more chlorogenic acid. Multiple coffee studies indicate that this compound helps raise HDL cholesterol and has potential benefits such as protecting the liver and slowing arteriosclerosis. Combined with the rise of the natural diet trend in recent years, specialty black coffee has become even more sought after.

On the extraction level, light-roasted coffee's cell walls are less damaged, so at Front Street we can adopt a relatively "aggressive" approach: fine grind (fine sugar size), high water temperature (about 88–92°C), strong water flow with agitation (raising the pour-over kettle high, swinging the kettle to apply pressure, etc.), and a high water-to-coffee ratio (about 1:13.33–1:16.67).

Of course, this is only a general summary. Everyone prefers different tastes, so the suitable approach will naturally vary.

Light roasting is simply too popular in the domestic coffee scene—so popular that many enthusiasts shake their heads and sigh the moment they see dark-roasted beans, blurting out "Chinese herbal medicine." This phenomenon is not surprising. Trends reflect market demand, and market demand is limited by the level of knowledge dissemination.

As the representative of the second wave of coffee, Starbucks naturally carries the label of being the opposite of specialty coffee, so many people also avoid the dark-roasted beans Starbucks champions, even concluding that "only bad beans use dark roasting to mask off-flavors," "after dark roasting everything tastes the same—you can't taste any flavor characteristics at all," "dark-roasted beans are unhealthy"...

Is that really true? Today, Front Street is here to talk about whether specialty coffee can actually be dark-roasted.

First, let's discuss why dark roasting exists.

First: discussing from the current mainstream SCA system

From the perspective of the current mainstream SCA system, a darker roast can temper acidity that is too strong and sharp. For example, why were Mandheling and Kenya AA often given a darker roast in the past? The reason is that the origin and processing method give these two beans intense acidity, and dark roasting largely softens the acidity's stimulation of the tongue, transforming it into sweetness and body.

Second: discussing from the concept of the old Japanese kissaten

Mention dark roast and many people instinctively add the prefix "Japanese," just as when mentioning light roast, Front Street first thinks of Nordic light roast. When it comes to dark roasting, one cannot avoid Japanese coffee. In the coffee philosophy of old Japanese kissaten, what they value is that coffee should have the richest layers and an elegant bittersweet taste. As for the former, the source of coffee's flavor includes not only the bean's own flavors but also the flavors that roasting can impart. The third wave specialty coffee approach is to preserve the former as much as possible; the old Japanese kissaten approach is to strive for the maximum of the sum of both.

Furthermore, the Japanese coffee philosophy differs from the SCA system in that it also includes an elegant bittersweet taste (not a burnt bitterness) within the category of good flavors (the SCA does the opposite). Under long-standing cultural habits, a darker roast level has thus naturally become the exclusive taste memory of Japanese kissaten.

Our imagination of dark roast mostly involves burnt bitterness and smokiness, mainly because dark roasting is usually handled with high heat and a fast roast, whereas Japanese roasting insists on low heat and a slow roast. Therefore, at the same dark roast level, the Japanese approach is relatively more likely to retain more of the coffee's sweetness and body.

So does that mean darker roasts don't use good beans, since the flavor comes out roughly the same anyway?

Of course not!

It is not that better beef is unsuited to sukiyaki, nor that better fish is unsuited to clay-pot fish head. Using better ingredients is absolutely different from the taste presented by using inferior ingredients.

If you have the fortune to drink an extremely dark roast of specialty-grade coffee beans at an old Japanese kissaten, and then compare it with an extremely dark roast of ordinary-batch coffee beans, you will find a clear gap between the two in sweetness, aroma, and layers. It is absolutely not the case that any roaster and any green bean taste roughly the same when dark-roasted—the key still depends on whether the roaster's skill is up to par and whether the green bean quality is excellent.

This is also why a good dark roast is always harder to find than a good light roast.

Even setting aside taste preferences shaped by regional cultures, dark roasting demands more from roasting precision, control, and the focused attention time required than light roasting does.

I once heard that for a good "charcoal-roasted coffee," a coffee master needs at least 30 to 40 years to produce excellent and stable quality. Although that was an era before data assisted the accumulation of experience, it is enough to illustrate the difficulty of dark roasting. The reason dark roasting has become "non-mainstream" in the specialty coffee world is not unrelated to its harsh demands on accumulated experience.

If you have the chance to visit an old kissaten in Japan that sells specialty coffee, please "by all means" give it a try... Of course, the prerequisites must be met: 1. it is specialty grade 2. the master's skill is authentic 3. the master's seniority is sufficient—only then can you taste a dark-roasted coffee flavor you will never forget!

And dark roasting is absolutely not a less healthy bean.

As long as it is a dark-roasted bean handled "with proper and skilled technique," the impact of charred substances on the human body can be largely avoided. Dark-roasted coffee beans also degrade more trigonelline and generate more niacin (commonly known as vitamin B3), which is also a beneficial component for the human body.

In recent years, scientists have also discovered that coffee contains various chemical substances that stimulate gastric acid secretion. During the research, they unexpectedly found an active substance, NMP (N-methylpyridium), which can block the ability of stomach cells to produce hydrochloric acid and reduce stomach discomfort.

Interestingly, NMP does not exist in green coffee beans; it must be produced through the roasting process, and the darker the roast, the higher the content—meaning drinking dark-roasted coffee is relatively gentler on the stomach. In addition, the acidic substances that easily cause stomach discomfort are present in smaller amounts in dark-roasted beans. Veronika Somoza, a professor in the Department of Nutritional and Physiological Chemistry at the University of Vienna in Austria, who led the research, pointed out that the NMP content in dark-roasted coffee may be more than double that in light-roasted coffee. So, do you easily get a cold stomach or heartburn from drinking light-roasted coffee? Then you may be better suited to coffee roasted a bit darker.

However, from smell and appearance alone, it is truly difficult to judge whether a bean is "properly dark-roasted" or "burnt"; just like steak, "burnt" and "a perfect Maillard reaction crust" are separated by a fine line. So can the winner only be determined by taste?

Unfortunately, dark-roasted coffee does have relatively fewer extractable substances than light roast, and because the cell walls are severely damaged, it is also much easier to extract than light roast. If you still brew dark roast using the method for light roast, you can well imagine it will come out burnt and bitter. These two roast levels differ too greatly in the degree of cell wall damage, so the extraction concepts are also quite different. To brew a cup of sweet, full-bodied dark-roasted coffee still requires great care.

Unlike light roast, the aroma and sweetness of dark roast are provided by relatively larger-molecule "brown pigments," so a relatively longer extraction time is needed. But because it is also easy to extract, you need to "minimize agitation as much as possible"—in other words, "treat the coffee grounds as gently as possible," pouring water slowly, to achieve both requirements at once. Today, Front Street Coffee (FrontStreet Coffee) will share up to here. Wishing everyone happy brewing~

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