Does Coffee Chaff Really Affect Flavor? A Rational Look at Silver Skin in Coffee Brewing

 When people talk about the chaff left on roasted coffee beans, a lot of them immediately say it negatively affects flavor and mouthfeel. Over time, it’s almost become something coffee enthusiasts are “afraid” of. Some cafés, in pursuit of absolute precision, even use air blowers to remove chaff from the grounds before brewing.

Honestly, I’ve been making coffee for more than a decade, and I still haven’t really “gotten” what kind of dramatic flavor impact chaff is supposedly having during brewing. I’ve always enjoyed my coffee just fine, and I’ve never felt that chaff was the enemy of flavor. From my own experience, its influence has never seemed large enough to enter the range of human sensory perception.

So I figured I’d throw this topic out there and open up the discussion. I’d genuinely like to hear how other people see it too.

First, let’s clarify a few basic concepts. What exactly is “coffee chaff”?

Chaff is the final thin protective layer attached to the surface of the coffee seed (the green bean). Botanically speaking, it’s part of the seed coat. Chemically, it consists of roughly 40–50% cellulose and hemicellulose, which mainly provide structural support, along with about 10–15% polyphenols such as chlorogenic acids and catechins, 5–8% mineral ash, and trace amounts of proteins and reducing sugars. During roasting, it becomes extremely light and easily blows away in the hot air.

When we judge whether a coffee is washed or natural processed, one surprisingly obvious clue is the amount of chaff visible after grinding. Washed coffees usually show noticeably more chaff, while natural coffees often have very little.

Why is that?

The original goal of the washed process is to remove the fruit skin and pulp, but the chaff itself is attached directly to the surface of the green bean, making it difficult to remove during processing. On top of that, most washed coffees today are roasted relatively light. With lighter roasts, the beans expand less during roasting, meaning the chaff doesn’t fully detach and tends to remain trapped in the center crease of the bean. So the lighter roast level is another reason washed coffees often retain more chaff.

Now let’s get to the real question: how much does chaff actually affect the flavor of a brewed cup of coffee?

Any discussion about “impact” has to involve quantity. Talking about effects without talking about dosage is meaningless.

Let’s do a rough calculation.

Suppose we brew a cup using 15 grams of coffee beans. In green coffee, chaff accounts for about 1–2% of the bean’s weight. After roasting, a portion of it falls off — especially in darker roasts. The amount remaining on roasted beans is typically around 0.2–1% of the roasted bean weight. Light-roasted washed coffees retain more, so let’s estimate around 0.5–1%.

Using the midpoint:

15g × 0.7% ≈ 0.105g of chaff.

To put that into perspective, 0.1 grams of chaff is roughly equivalent to the volume of two or three sesame seeds.

In pour-over brewing, only a small fraction of the polyphenols inside the chaff are actually soluble. Chaff is lightweight and somewhat hydrophobic, often floating on the surface during brewing, which makes it difficult to extract efficiently. The amount of dissolved material from the chaff that actually ends up in the cup may be less than 0.01 grams.

Compare that to the coffee grounds themselves: 15 grams of coffee typically yield around 2.1–2.7 grams of soluble compounds during extraction.

That means the soluble contribution from chaff accounts for less than 0.5% of the total extraction. Human flavor perception thresholds generally require at least a 1–2% change in concentration before most people can clearly notice a difference. In a properly filtered cup of coffee, the contribution of chaff falls below the average human sensory discrimination threshold.

So here comes the next question:

If that’s the case, why do so many people insist that chaff affects flavor?

Well, there probably is some basis for those observations. The key is that different brewing methods can produce different results.

For immersion-style brewing methods, the experience may indeed change slightly. In fact, coffee cupping itself is a classic immersion extraction method, and you may occasionally notice a faint astringency. That sensation likely comes from polyphenols in the chaff dissolving during high-temperature extraction.

But when looking at the overall flavor of an entire cup, that tiny bit of astringency is nowhere near as intense as the chlorogenic acids already naturally present in the coffee itself.

There was also a trend online where people intentionally collected large amounts of chaff and brewed it separately. Some described the flavor as “diluted grain husk water” with a mild dryness or astringency. From there, people jumped to the conclusion that chaff must significantly affect flavor and mouthfeel in normal coffee brewing.

Personally, I think instead of obsessing over a few tenths of a gram of chaff, it makes far more sense to focus on grind consistency, water temperature, and pouring technique. Those are the factors that truly determine whether a cup of coffee tastes great or not.

UFO Coffee Dripper Review: The 80° Cone Design That Boosts Sweetness & Clarity

 This UFO-shaped dripper might look like a gimmick at first glance, but its design is anything but superficial. It actually rethinks the fundamental logic of the classic conical dripper—and that genuinely caught my attention. I’m planning to dive deeper into its design principles and extraction benefits before deciding whether to pick one up and share my hands-on experience with you all.

At its core, the UFO dripper still follows a conical structure. However, both its opening angle and overall form differ significantly from most standard cone drippers. The most notable shift? It moves from what we typically think of as a V60 to something closer to a “V80.” Yes—an 80° cone angle. This steeper angle accelerates water flow. On top of that, instead of the usual raised internal ribs, it features recessed ribs. The combination of an 80° cone and concave ribbing works like a double boost: it concentrates water flow, reduces channeling, and ultimately leads to a more even extraction—bringing out brighter acidity and more expressive aromatics in the coffee.

Let’s break it down further.

At first glance, the dripper appears short and wide. If you look closely at the walls, you’ll notice it’s made of thick ceramic—but not with uniform thickness. The upper wall is actually about 23.7% thinner than the lower section. The rim flares outward like a flying saucer, creating a wide lip. This isn’t just aesthetic—it serves a functional purpose. During brewing, heat naturally rises. The space formed between the wide rim and the top of the filter paper allows steam to escape more efficiently, preventing it from accumulating and condensing back into the brew. This helps maintain airflow above the dripper, stabilizing extraction temperature and avoiding overheating in the upper coffee bed—which can otherwise lead to a “steamed” or overcooked taste.

Now, consider this: when the base diameter and dose remain constant, increasing the cone angle spreads the coffee bed wider and reduces its vertical height. This shortens the distance water travels through the grounds, increases the surface area for flow, and lowers resistance per unit area—resulting in a faster overall flow rate. The outcome? A cup that leans toward higher sweetness, lower bitterness, and a cleaner, more refreshing profile.

But there’s a trade-off. A shallower bed combined with faster flow can lead to under-extraction if left unchecked. That’s where the recessed ribs come into play. They prevent water from taking shortcuts along the edges and ensure it passes through the coffee bed. In other words, they act as a forced flow-guidance system, compensating for the reduced contact time caused by the shallower bed.

This type of concave rib design isn’t entirely new—it has appeared in several classic drippers—but compared to the raised spiral ribs of a traditional V60, it offers some distinct advantages. The recessed vertical grooves create a physical buffer zone between the filter paper and the dripper wall. In conventional designs, water can easily slip along the wet filter paper and bypass the coffee bed (a phenomenon known as bypass flow). Here, those grooves “catch” the water and redirect it downward. By blocking edge channels, the design forces water to pass more evenly through the center of the coffee bed, significantly reducing channeling and improving extraction consistency.

This also means the dripper is more forgiving. Even if your pouring technique isn’t perfect—or if your stream hits the edges—the flow system helps guide the water back on track.

As a result, this dripper shows clear advantages when brewing light roasts or coffees with pronounced floral and fruity notes. Think Geisha or Yirgacheffe: you can expect lifted aromatics, lively acidity, and a clean finish with minimal bitterness or woody astringency—even toward the end of the brew.

That said, there’s one important caveat: this dripper is not compatible with standard filter papers. It requires specially designed UFO filters. Interestingly, these filters aren’t made from traditional paper pulp—they’re composed of a food-safe blend of lyocell and PLA. This means you can skip pre-rinsing without worrying about papery off-flavors.

There are two types of filters: Type A and Type F. “F” stands for fast, while “A” stands for average. Compared to A, the F filter is larger. Type A is designed to produce a brighter, more balanced cup, and is generally sufficient for standard use. Type F, on the other hand, enhances body and works well for hybrid immersion-drip brewing methods.

The manufacturer also provides recommended brewing parameters:

For Type F filters (baseline):

• Grind size: 800–1100 μm (Comandante C40: 22–27 clicks)
• Ratio: 15g coffee to 250g water (1:16.67)
  • For more body, increase dose to 16.6g (1:15)
• Water temperature: 92°C ±4°C
  • Dark roast: ~88°C
  • Very light roast: up to 96°C

Pouring structure:

• 00:00–01:00: 50g (circular pour)
• 01:00–01:30: 50g (circular)
• 01:30–02:00: 50g (circular)
• 02:00–02:30: 100g (center pour)

For Type A filters (baseline):

• Grind size: 1000–1300 μm
• Ratio:
  • 13.5g : 225g (lighter, tea-like body)
  • 15g : 225g (juicier mouthfeel)
• Water temperature: 92°C

Pouring structure:

• 00:00–00:30: 45g (circular)
• 00:30–01:00: 45g (circular)
• 01:00–01:30: 45g (circular)
• 01:30–02:00: 45g (center)
• 02:00–03:30: 45g (center)
• Total brew time: under 3.5 minutes

For iced pour-over (Type A):

• Grind size: 1100–1400 μm
• Ratio: 20g coffee : 200g water
• Water temperature: 92°C

Pouring structure:

• 00:00–00:30: 50g (circular)
• 00:30–01:00: 50g (circular)
• 01:00–01:30: 50g (circular)
• 01:30–03:00: 50g (center)

Brew hot, then pour directly over a glass filled with ice and enjoy.

They’ve also released a UFO Dripper V2 made from durable, heat-resistant Tritan, which is better suited for immersion-drip hybrid brewing with Type F filters. I won’t go too deep into that here.

The brand has also collaborated on various limited-edition releases, including filter papers with Spain-based SIBARIST and handmade ceramic drippers with multiple studios. One standout collaboration, in my opinion, is with MK Studio—a Copenhagen-based ceramics studio founded by Magdalena and Michal, a husband-and-wife team. Combining Michal’s background as a chef with Magdalena’s expertise in ceramics, they blend culinary sensibility with artistic craftsmanship. Their take on the UFO dripper is more expressive and artistic, with each color limited to just 60 pieces worldwide—though they’re likely sold out by now.

To wrap it up: from concept to execution, this dripper feels thoughtfully designed and logically consistent. It’s best suited for intermediate to advanced brewers who have some control over their technique. If you’re looking to highlight delicate notes like fruit acidity and florals—and push your pour-over experience to the next level—this might just become your new favorite brewing “toy.”

The Crazy Evolution of Coffee Filter Paper: How Filter Choice Changes Pour Over Coffee Flavor

 When it comes to coffee extraction—whether it's espresso or pour-over—there’s one thing you simply can’t avoid: the filter paper.

This small sheet of paper has quietly evolved over the past few years alongside the technological development of specialty coffee. In fact, its evolution has been so dramatic that the word “crazy” might not be an exaggeration. This “craziness” includes innovations in materials, upgrades in functionality, and of course, some pretty crazy price tags as well—haha.

Today, I’d like to talk about why filter papers in coffee extraction keep evolving. What exactly are people pursuing when they aim for the ultimate cup of coffee? And what role can filter paper play in shaping the final result? Let’s dive into the “crazy evolution” of coffee filter papers.

Different filter papers vary in density, thickness, structure, and permeability, and these factors directly determine the flow rate. Flow rate, in turn, affects coffee extraction, flavor, and mouthfeel.

Filter paper is no longer just a simple barrier separating coffee grounds from water, nor is it merely about achieving a cleaner cup. Today, it has moved far beyond its basic function and plays a significant role in shaping the extraction process.

Under the philosophy of precise and controllable brewing, filter papers can now be chosen specifically for different roast profiles or processing methods, allowing more targeted brewing experiments. By selecting different types of filter paper, brewers can effectively improve clarity, sweetness, and roundness in the cup.

Filter papers have evolved from simple pulp-based materials into products with carefully engineered density, fiber structure, permeability, and even hydrophobic properties. Their impact is quite noticeable because they introduce a meaningful variable into the brewing process.

During this evolution, several brands have become particularly representative—especially those that focus on producing functional filter papers. One of the most iconic examples is Sibarist. I’ve previously written about many of their products, from their early fast-flow filter paper designed for the Hario V60 to their later DUAL CHAMBER layered filters.

Another example is CAFEC, which produces filter papers designed for different roast levels. Then there’s KINTO with its well-known silky slow-flow filter papers.

All of these filter papers share one key characteristic: they help baristas control the flow rate through the material’s texture and structural properties.

And yes—flow rate control is a crucial factor in coffee extraction. Filter paper may seem like a minor variable, but its impact is clearly visible and perceptible in the final cup.

It influences how water flows through the coffee bed and controls how compounds such as oils, sugars, and acids enter the final brew. This directly affects the mouthfeel and flavor balance.

Let’s take CAFEC filter papers as an example.

For light roasts, the recommended filter has a thickness of 0.15 mm, making it the thinnest of the three. The inner surface has no crepe texture, which results in a smaller internal surface area. Coffee fines attach to this small area, leaving fewer channels for water flow, causing water to accumulate inside the filter.

During brewing, this slows down the flow rate and allows more aromatic compounds to develop. Meanwhile, the crepe texture on the outer side allows the brewed coffee to flow out smoothly. The higher density of the paper also helps prevent fine particles from passing through, ideally producing a cup that is aromatic and clean.

Next is the T-90 filter, designed for medium to dark roasts, with a thickness of 0.28 mm, making it the thickest of the three.

Both the inner and outer surfaces feature crepe textures, creating double-sided creping that allows water to flow most smoothly. Among the three filters, it also provides the largest surface area and relatively lower density. Even if fines attach to the filter surface, the flow rate remains stable.

The goal here is to produce a balanced and full-bodied flavor, enhancing both sweetness and richness.

The T-83 filter, designed for dark roasts, has a thickness of 0.22 mm, placing it in the middle in terms of both thickness and density. It also features double-sided creping, but with a unique design: the crepe height is intentionally kept lower.

In other words, most of the crepe structure is concentrated closer to the bottom of the filter near the dripper’s outlet. During the first half of brewing, when fewer fines have accumulated, water flows relatively smoothly. In the later stage, as more fines attach to the filter, the flow slows down. This helps promote a stronger body and enhanced sweetness in the final cup.

It’s fascinating, isn’t it? Even such a small piece of paper can have a significant impact.

Thinking back 10 or 15 years ago, people were mostly debating whether to buy bleached filter paper or natural (unbleached) filter paper. Today, filter paper selection has become far more multidimensional. Many products are now designed with specific functions to match particular brewing devices or coffee bean characteristics.

This evolution is a natural result of the continuous advancement of brewing equipment, as well as the increasing diversity of coffee processing and roasting techniques.

Flavor compounds in coffee dissolve at different rates. Some extract quickly with hot water, while others require longer contact time.

Based on this principle, differences in filter paper permeability can help extract specific combinations of soluble compounds. For example, the classic FAST filter paper from Sibarist is designed to increase extraction yield within a shorter brewing time. It emphasizes compounds extracted early in the brewing process, highlighting acidity, complexity, and flavor vibrancy.

So when choosing filter papers for everyday brewing, what basic principles should we follow?

Here are a few general guidelines. Of course, they’re only references—you should always adjust based on your own brewing practice and flavor preferences.

From a flavor perspective, if you enjoy delicate, floral, or high-acidity profiles, a fast-flow filter is often a good choice. It helps maintain clarity, aromatic complexity, and a lighter mouthfeel, making the coffee feel more elegant and refined.

On the other hand, if you prefer coffee with strong body and noticeable sweetness, you might choose a denser filter paper and pair it with a longer extraction time to build deeper sweetness and a richer texture.

Another factor to consider is your brewing device.

If you’re using a dripper that tends toward immersion-style extraction, such as a slow-drip system, pairing it with a faster-flow filter paper can help prevent over-extraction while maintaining clarity and flavor definition.

You can also take the coffee processing method into account.

Washed coffees usually contain less surface oil because most of the oils remain locked within the bean’s cellular structure. As a result, they often require a longer extraction time to release more oils and aromatic compounds.

Natural (sun-dried) coffees, on the other hand, tend to have higher surface oil content and release soluble compounds more quickly. In such cases, pairing them with a faster-flow filter can work well.

That said, nothing replaces hands-on experimentation.

Try brewing the same coffee with the same equipment but using different types of filter papers. Pay attention to how the mouthfeel, clarity, and balance of the coffee change.

You might be surprised by how much difference that small piece of paper can make—and hopefully, you’ll have some interesting brewing insights to share with others as well.

Why Cafés Filter Crema From Americanos | Clean Taste vs Traditional Espresso

 This question is something I’ve noticed quite frequently over the past year while café hopping. Of course, it’s not a new topic for me—I’ve already touched on it multiple times in previous articles. Personally, I’ve encountered it so often that I’ve almost become “desensitized” to the idea of filtering crema from an Americano. But if we take a more rational step back, the reason many cafés now promote over-extraction–style Americanos is fairly clear: they’re chasing a cleaner, more stable, and smoother mouthfeel, while trying to avoid unpleasant flavors.

From my point of view, over-extraction–based Americanos and traditional “espresso + water” Americanos follow fundamentally different extraction and brewing logics. In that context, removing the crema can be a 1 + 1 > 2 kind of optimization. However, if it’s just a standard espresso shot that’s brewed normally, then filtered for crema, and only afterward diluted with water, I personally feel it would be better to leave the crema intact. After all, that crema is the soul of the espresso.

So why do so many cafés filter out the crema when serving an Americano? It’s undeniably a widespread and discussion-worthy phenomenon in today’s specialty coffee scene. By “crema,” I’m referring to the oily substances in coffee beans (along with some ultra-fine coffee particles). Strictly speaking, this isn’t true oil. Rather, it’s a stable, oil-like foam formed through emulsification under high pressure—what we commonly call crema.

Not long ago, I talked about how crema is often considered the soul of espresso, and I believe many people still hold that view. In traditional Italian coffee culture, a perfect espresso is expected to have a thick, fine, brown crema on top. It’s seen as a marker of freshness and successful extraction, contributing to a richer mouthfeel and longer-lasting aroma. In some evaluation systems, the color and thickness of the crema are even key scoring criteria. What we’re seeing now is, to some extent, a departure from that tradition—a redefinition of how we understand espresso’s role as a base in beverages like the Americano.

I think this shift also reflects how people’s flavor preferences have evolved. The industry has gradually moved away from the classic pursuit of “intense, bitter, and heavy-bodied” coffee toward a preference for “clean, sweet, and transparent” flavors. Under this new paradigm, crema can sometimes work against the desired profile. Crema contains a relatively high concentration of compounds such as quinic acids, which can introduce sharp, lingering bitterness and astringency.

This becomes even more apparent now that many espresso programs favor light or light-medium roasts, aiming to highlight fruity notes, floral aromas, and bright acidity even in espresso. In such cases, the bitterness and harshness associated with crema can easily overshadow the coffee’s elegant origin characteristics.

In China, drinking espresso straight is still relatively uncommon, but I’d still like to point out one thing: if you are going to drink espresso on its own, it’s important to stir the crema thoroughly into the liquid before drinking. Otherwise, the crema can actually detract from the overall mouthfeel. Also, the flavor of crema changes over time. Fresh crema tastes very different from crema that has been sitting for a few minutes—it oxidizes and breaks down, becoming less pleasant. In that sense, the problem isn’t always the crema itself, but sometimes the way we approach drinking it.

Another key consideration is consistency. The amount of crema varies from shot to shot, which means each Americano can look slightly different and deliver a subtly different initial taste. If there are roasting defects, crema can further amplify undesirable flavors such as burnt bitterness, smokiness, or rubbery notes. By filtering out the crema, cafés can make every cup look clear and uniform, while also reducing the amplification of flavor flaws in the finished Americano.

On top of that, cafés today are highly visual spaces. The appearance of a drink matters. When espresso is poured directly into water, the crema floats on the surface, and that foamy layer isn’t always visually appealing. Sometimes it breaks apart awkwardly or clings to the sides of the cup. To many consumers, that’s the very definition of “not photogenic.” It’s only natural, then, that cafés would try to avoid this and gradually adopt crema filtration as a standard practice.

Seen this way, filtering crema from an Americano is essentially a deliberate choice—a form of flavor selection and mouthfeel optimization. It also introduces a new layer of dialogue at the point of ordering. If you’re someone who loves crema, it’s worth asking whether the café filters it by default. And if you enjoy the richness and heavier body that crema brings, you may want to ask the barista not to filter it out.

In the end, there’s no right or wrong when it comes to flavor and texture—only personal preference. In that sense, the Americano has gained yet another dimension of choice. And perhaps, on a deeper level, this trend reflects a more nuanced understanding of quality within the industry, as well as a growing respect for the diversity of consumer tastes.

Why You Shouldn’t Brew Small Coffee Doses with a Large Dripper (V60 Brewing Tips)

 We all know that coffee drippers usually come in two sizes—large and small. Some people assume that if a large dripper can handle a big dose of coffee, it should naturally work just fine for a smaller dose as well. So why not just buy one large dripper and call it a day?

In reality, that way of thinking isn’t ideal. Today, let’s talk about why using a large dripper to brew a small dose of coffee is generally not recommended. Hopefully, this will be helpful—and if it is, feel free to share it with your fellow coffee friends.

First, let’s clarify two concepts: how big is a “large” dripper, and how small is a “small” dose?

Let’s use the V60 as an example. A V60 labeled 02 is considered a large dripper, designed for brewing coffee for 1–4 people. A “small” dose, in this context, refers to using around 15 grams of coffee, typically brewed at a 1:15 coffee-to-water ratio.

When a large dripper is designed, it’s meant to accommodate a larger amount of coffee grounds—usually 20–30 grams or more—which naturally creates a thicker coffee bed. If you only use 15 grams of coffee in such a dripper, the risk of uneven extraction increases significantly. The result is often a cup that tastes thin, sharp, overly acidic, or bitter.

Because a large dripper has a wider diameter, a small dose of coffee spreads out into a very thin coffee bed. During brewing, hot water passes through this thin bed much too quickly, making it difficult to evenly saturate and extract all the grounds. This leads to poor control over both water flow and temperature.

One of the most serious problems during extraction is channeling. Water naturally seeks the path of least resistance, and in a thin coffee bed, it’s very easy for fixed channels to form. Most of the water rushes through these channels, while other areas of the coffee bed barely get extracted at all.

The result is the worst of both worlds:

• The areas where water channels through become over-extracted, producing bitterness.

• The areas that don’t get enough water remain under-extracted, leading to sharp acidity and hollow flavors.

As you can imagine, the final cup is far from pleasant.

There’s also a secondary factor to consider: heat retention. Large drippers—especially ceramic or glass ones—have more mass and therefore require more hot water to preheat properly. If preheating isn’t sufficient, the cold dripper will quickly absorb heat from the brewing water.

On top of that, a thin coffee bed holds very little heat on its own. Combined with the large opening of a big dripper, which increases exposure to air, the overall brewing temperature drops too quickly. Unstable water temperature and excessive heat loss often lead to under-extraction, further increasing the chances of ending up with a disappointing cup.

With a large V60 like the 02, using a small dose also makes pouring much more difficult. The steep cone angle and wide interior space mean that water can easily hit the filter paper along the sides, washing away the coffee bed or disturbing its structure. This greatly increases the likelihood of channeling.

Even if you pour very gently and precisely, getting such a thin coffee bed to bloom and expand evenly requires a high level of skill. It’s not something most everyday coffee enthusiasts can easily pull off.

That’s why, in daily brewing, it’s important to match your coffee dose to the appropriate dripper size. If you usually brew around 15–18 grams of coffee, a small dripper is the better choice—whether that’s a V60-01, a Kalita 155, or another similar model.

With a small dripper, a small dose can form an ideal coffee bed thickness. Water is forced to pass more evenly through all the grounds, the dripper is easier to preheat, heat loss is slower, and the narrower opening naturally directs water toward the center of the coffee bed. All of this makes it much easier to achieve a balanced and even extraction.

Finally, there’s one awkward but very real question to address:
What if you already own a large dripper—and only a large dripper—and still want to brew small doses?

While the best solution is still to get a properly sized small dripper, here are a few compromise strategies you can try if a large dripper is all you have for now:

• Grind finer: A finer grind increases resistance, slows down the flow rate, and extends extraction time, allowing more flavor compounds to dissolve.

• Lower the water temperature: Try brewing at around 88–91°C (190–196°F). Slightly cooler water can help prevent overly rapid extraction of bitter compounds.

• Adjust your pouring technique: Use a thinner stream of water and pour more gently and slowly.

• Use multiple pours: After blooming with a small amount of water, continue brewing with several smaller pours. Wait for the water level to drop before each pour to extend the total extraction time.

These adjustments won’t fully replace the benefits of a correctly sized dripper, but they can help improve your results until you’re able to switch to one that truly matches your brewing needs.

Why Does Pour Over Coffee Taste Burnt and Bitter? 4 Common Brewing Mistakes Beginners Make

 Beginners often say that brewing coffee feels like pure guesswork—that whether it tastes good or not is all about luck. But in my view, once you understand the logic and patterns behind brewing, you’ll realize it’s not complicated at all. It really comes down to identifying a few key variables and using hot water to properly extract the coffee grounds. Do that right, and you’ll end up with a genuinely good cup of coffee.

These days, the internet is flooded with brewing tutorials. And yet, many beginners still run into an “unexpected” problem: the coffee they brew tastes harsh, burnt, and unpleasantly bitter. Today, I want to walk you through a process of elimination to help you pinpoint the cause.

Reason 1: The Coffee Beans Are Dark Roasted

Whether coffee tastes acidic or bitter is largely determined by the roast level. Light roasts tend to emphasize acidity, dark roasts highlight bitterness, and medium roasts sit somewhere in between.

For people who enjoy dark-roasted coffee, these beans offer aromas like caramel, nuts, chocolate, toasted bread, and similar flavors. The mouthfeel is usually heavier, richer, and more rounded, with a long-lasting aftertaste that lingers pleasantly.

However, if you’re not naturally drawn to bold, intense flavors, this style of coffee can feel overwhelming. Because dark roasts are dominated by roast-derived aromas, many people describe them as tasting burnt and bitter—some even compare them to traditional herbal teas.

Avoiding this is actually quite simple. Just look at the flavor notes on the coffee bag. For example, beans labeled with flavors like chocolate, nuts, toasted bread, spices, pine, or caramel—such as Brazil Cerrado, Colombia Huila, or Indonesia Mandheling—are clearly roast-driven profiles. These are typically bitter-forward coffees produced through longer roasting.

Reason 2: The Beans Are Too Old and Have Lost Their Aroma

Beyond roast level, bitterness is also closely tied to freshness.

After roasting, coffee beans release a large amount of carbon dioxide in the first few days. They then enter a “golden window” when aromas peak and flavors are at their best. As time goes on, those flavor compounds gradually fade, the aroma weakens, and the cup becomes flatter and duller.

My general recommendation is this: if the beans are kept whole, try to finish them within six weeks of roasting. Once they’re ground, it’s best to use them within three weeks.

If your beans are dark-roasted, fresh beans will smell strongly of roasted aromas—what many people simply call “that coffee smell.” But once they pass their prime, not only does that aroma disappear, you may start to notice off-notes like woodiness, oiliness, or smokiness. When brewed, these beans often produce a cup with an inherent burnt bitterness.

If you’ve ruled out the beans themselves, then the bitterness is most likely coming from your brewing parameters.

Reason 3: The Grind Is Too Fine, or There’s Too Much Fine Powder

From what I’ve observed, most cases of burnt or bitter coffee among beginners are related to grind size. This usually shows up in two ways.

The first is grinding too fine. When the grind is too fine, water struggles to flow through the bed, leading to excessive contact time and over-extraction—resulting in bitterness.

The second is having too many fines. These tiny particles clog the pores of the filter paper, slowing the flow and causing channeling or blockage, which also leads to over-extraction.

If your water flow is steady but overall very slow—for example, 15 grams of coffee at a 1:15 ratio taking longer than 2 minutes and 20 seconds—and the cup tastes burnt and bitter, your grind is likely too fine. Adjust it coarser.

If the water flows normally at the beginning but slows down significantly toward the end, and the coffee bed looks muddy and waterlogged after brewing, that’s a sign of too many fines. In this case, you can sift out some of the fines or consider upgrading to a better-quality grinder to reduce their presence.

Reason 4: The Water Temperature Is Too High

When it comes to water temperature, I rarely recommend a single fixed number. Instead, I suggest a general range based on roast level:

• Light to light-medium roasts: 91–93°C (196–199°F)

• Medium roasts: 89–91°C (192–196°F)

• Dark roasts: 86–88°C (187–190°F)

That said, even within these ranges, small differences matter. The flavor extracted at the upper end of the range can be noticeably different from the lower end. Sometimes, a burnt bitterness comes down to just a 1–2°C difference.

I remember brewing Jamaica Blue Mountain No. 1 with 88°C water and noticing a slightly burnt, bitter finish. Keeping all other variables the same, I lowered the water temperature to 86°C. The result was an immediate improvement—the cup became cleaner, more balanced, and far more pleasant.

If your coffee tastes burnt and bitter, and you’ve already ruled out roast level, freshness, and grind size, it’s worth considering whether your water temperature might simply be too high.

Understanding these variables—and adjusting them one by one—will take the guesswork out of brewing and bring you much closer to consistently great coffee.

Why Water Quality Matters in Pour-Over Coffee (Alkalinity, Hardness & Flavor Explained)

 The coffee we drink is, at its core, water that has dissolved the flavorful compounds inside coffee grounds. In fact, more than 98% of a cup of pour-over coffee is water.

We spend so much time chasing the best origins and growing regions, the most suitable processing methods, the perfect roast profiles, and the most precise brewing techniques—yet all of these efforts ultimately rely on water to carry the coffee’s flavor. If we overlook the foundational role of water, everything else can easily fall apart.

**No.1

Water Plays Two Core Roles in Coffee Brewing: Extraction and Flavor**

Water is responsible for extracting soluble flavor compounds from coffee grounds, and it also makes up the body of the final beverage itself. The chemical composition of the water directly influences what ends up in your cup.

**No.2

The Soluble Compounds in Water: Alkalinity and Hardness**

Water contains both negatively charged ions and positively charged ions.

• The concentration of negatively charged ions determines total alkalinity

• The concentration of positively charged ions determines total hardness

1. Total Alkalinity — Mainly Bicarbonate Ions

Bicarbonate ions act as a buffer in brewing water, helping neutralize acidity and keep the pH within a suitable range. The higher the bicarbonate content, the higher the alkalinity, and the stronger its ability to suppress acidic compounds in coffee.

When alkalinity is too high, it can neutralize or even mask coffee’s pleasant natural acidity, making the cup taste dull, flat, or even slightly “soda-like,” while amplifying bitterness and reducing clarity.
When alkalinity is too low, buffering capacity weakens, causing acidity to become sharp, aggressive, and lacking roundness.

2. Total Hardness — Calcium and Magnesium Ions

Calcium and magnesium ions are highly effective at binding to coffee’s flavor compounds—especially desirable acids, sweetness, and oils. Without them, extraction efficiency drops significantly.

Magnesium is particularly good at extracting floral and fruity aromas, while calcium contributes more to body and mouthfeel. This is why some high-end brewing waters carefully adjust the calcium-to-magnesium ratio.

If hardness is too high (>150 ppm as CaCO₃), coffee tends to extract excessive bitterness and astringency, loses vibrancy, and forms scale on equipment.
If hardness is too low (<50 ppm as CaCO₃), the coffee tastes hollow, thin, overly acidic, and lacking sweetness and body.

According to the Specialty Coffee Association (SCA), recommended ranges are:

• Alkalinity: 40–75 ppm

• Total hardness: 50–175 ppm

  

**No.3

pH: Another Critical Water Parameter**

The SCA recommends a brewing water pH between 6.5 and 7.5, with an ideal target around 7.0.

pH measures acidity and alkalinity. Brewing coffee with alkaline water (pH above 7) reduces perceived acidity—the higher the pH, the stronger the buffering effect. Simply put:

• Higher pH → lower perceived acidity

• Lower pH → higher perceived acidity

However, higher alkalinity is not always better. Excessively alkaline water often leads to bitterness and astringency, dulling the coffee’s character.

**No.4

How to Create Better Brewing Water**

1. Test Your Water

Use a TDS meter or a dedicated water testing kit to understand your current brewing water.

2. Choose a Solution

(1) Basic Option: Filtered Water
Activated carbon filters remove chlorine, odors, and organic compounds, improving taste. While they have limited effect on hardness, they’re a solid starting point for most homes and cafés.

(2) Intermediate Option: Bottled Water Blending
Mixing low-mineral purified water with mineral water at specific ratios is an affordable and effective way to improve brewing water.

(3) Professional Option: Custom Brewing Water
Using third-party mineral packets or an RO (reverse osmosis) system with remineralization filters allows precise control. Many competition brewers use this approach to tailor water for specific coffees.

Water quality is one of the most underestimated variables in pour-over coffee. When we care about origin, processing, roast profiles, and brewing techniques, we should also care about the water we use—because that’s often the final key to unlocking a truly exceptional cup.

How to Brew a Clean Cup of Coffee | Pour Over Tips for Maximum Clarity

 There are many reasons why we might fall in love with a cup of coffee. It could be its rare and complex flavor profile, a rich and weighty mouthfeel, layered and evolving notes, or even the story behind where it comes from. Beyond these, there are also some more niche reasons. For example, I have quite a few friends who judge a coffee by one key word: “clean.”

Here, “clean” doesn’t mean visual clarity, nor does it mean a coffee with low flavor complexity or “nothing going on.” Instead, it refers to a cup that is free of any unpleasant off-flavors, with flavors that are well-defined and easy to distinguish. It may sound simple, but achieving this level of cleanliness actually places very high demands on coffee quality. From growing and processing to roasting and brewing—in short, every step from seed to cup needs to be handled with great care.

Before the concept of specialty coffee became widespread, exported green coffee was often processed in rough, unsophisticated ways by local farmers. As a result, it was common for coffee to carry undesirable flavor defects. In the old version of the SCAA flavor wheel, there was even a dedicated section known as the “negative flavor wheel.”

So what is the negative flavor wheel? It refers to flavors that are universally recognized as unpleasant—defective notes that make coffee uncomfortable to drink. As mentioned earlier, these defects can arise at many stages along the coffee chain. For example, when unripe beans are mixed in, the brewed coffee may exhibit grassy or hay-like flavors, usually caused by harvesting underripe cherries. Poor control during processing can lead to mold or over-fermentation, resulting in musty or moldy notes. Uneven roasting can cause scorching, producing smoky flavors, while underdeveloped roasts may bring out dry, hay-like characteristics.

Beyond outright defects, extraneous flavors also play a role in perceived cleanliness. These are flavors that detract from clarity. They include defects, but are not limited to them. For instance, imagine tasting a coffee whose main profile should be berries and citrus, but you also find notes of nuts, cocoa, or toasted bread mixed in. While these aren’t necessarily negative flavors on their own, when they appear in a fruit-forward coffee, they can make the cup feel cluttered and unfocused—like a room filled with good furniture, but arranged in complete chaos. This, too, is a sign of insufficient cleanliness.

With the arrival of the specialty coffee era, people at every stage of the supply chain have begun to prioritize quality. Fully ripe cherry harvesting has become standard practice in most producing regions, and processing techniques have grown increasingly refined. As a result, many undesirable flavors are eliminated right at the source. For us as end consumers, choosing a reliable roaster (for example… me—I’m very reliable) means that our attention can largely shift to the final step: brewing. With green buyers and roasters acting as multiple layers of quality control, it’s unlikely that truly poor-quality beans will end up in our hands.

That said, don’t underestimate the importance of brewing. Proper extraction is crucial to a coffee’s cleanliness. In most cases, when a cup lacks clarity and is filled with muddled flavors, the culprit is improper extraction. In pour-over brewing, for example, excessively high water temperature, overly fine grinding, overly long brew times, or aggressive pouring and agitation can all lead to over-extraction. This causes large bitter compounds to be released in excess, masking the coffee’s natural flavors with woody, harsh bitterness.

In addition, factors such as dirty brewing equipment with residual oils, filter papers with strong papery flavors, or coffee that is too fresh and carries a “green” or restless sharpness can all introduce unwanted notes and reduce clarity. So it’s not just about extraction parameters—every small detail during brewing needs to be carefully controlled. Only then can we brew a truly clean cup of coffee.

Generally speaking, if you start with high-quality beans and use reasonable extraction parameters, your coffee will almost always display excellent clarity. If you’d like to experience a particularly clean cup, I recommend trying two coffees from my lineup: Esmeralda Estate · Washed Green Label Geisha and Ethiopia · Natural ALO. Brew them with a water temperature of 92°C (198°F), a brew ratio of 1:16, an extraction time of 2:00–2:20, and a grind size where 75–80% passes through a #20 sieve.

With these parameters, you’ll get a beautifully clean cup. The former offers clearly defined notes of citrus, jasmine, and green tea, while the latter expresses mango, pineapple, and magnolia. Both are driven by bright acidity and gentle sweetness, with a silky, cream-like mouthfeel and a clear, uplifting sense of clarity.