The production of fines when grinding coffee beans is a normal phenomenon. A moderate amount of fines contributes positively to flavor; what truly causes trouble is excessive fines. Front Street Coffee has noticed that many coffee enthusiasts feel a sense of dread at the mere mention of fines, mostly because they have been tormented by clogged beds that won't drain, scorched bitterness, and astringency. This article first defines what particle size counts as fines, then explains the relationship between the causes of fines and the type of burr set, with a focus on comparing the differences among flat burrs, ghost-tooth burrs, and conical burrs in terms of grind uniformity and fines ratio. Finally, it offers two practical solutions: sifting out fines and adjusting brewing technique, along with rescue strategies for the common situation of abundant fines accompanied by coarse grounds that are also too coarse. [more…]

In the grinding stage of pour-over coffee, the production of fines is almost unavoidable. These tiny particles, with a diameter of less than 0.1mm and a texture close to flour, are far off from the target particle size of 0.6~0.8mm. The source of fines is related both to the brittleness of the coffee beans themselves and directly affected by the quality of the grinder. For coffee enthusiasts, understanding the dual nature of fines—they can both improve extraction efficiency and enrich complexity, and may also bring bitterness and clogging—is the key to brewing the ideal flavor. This article will analyze the causes of fines, the differences between coarse and fine particles, and strategies for dealing with them during pour-over brewing, and provide reference in combination with the practical experience of Front Street Coffee. [more…]

In the practice of pour-over coffee, fines are often seen as the culprit behind clogging and bitterness, and many people have thus developed the habit of always sifting out fines before brewing. But do fines really only have negative effects? From the perspective of Front Street, this article systematically sorts out the definition of fines, their generation mechanisms, and their actual contribution to flavor, explaining why in most cases it is unnecessary to completely sift out fines, and under what conditions sifting should really be considered. At the same time, the article also explores the relationship between coffee bean brittleness, grinder quality, and the amount of fines, helping readers build a more complete understanding of extraction. [more…]

In the coffee grinding process, the production of fines is almost an unavoidable phenomenon, regardless of whether one uses expensive professional-grade grinders or entry-level manual grinding equipment. However, the proportion of fines directly affects the stability of brewing and the final flavor presentation. Choosing a suitable grinder can, to a certain extent, help us reduce the troubles caused by fines. Front Street Coffee specifically conducted a comparative test on the differences in fines generation between manual coffee grinders and electric coffee grinders, analyzing the differences in grinding performance between the two from the perspective of burr structure, helping coffee enthusiasts more clearly understand the characteristics of different devices in grinding function, so as to make choices that better suit themselves. [more…]

In the making of espresso, fines have always been a love-hate presence. They may bring rich crema, but they can also clog the portafilter basket, slow down the flow, and add bitterness. There are two common methods for removing fines on the market: one is to skim off the surface crema after extraction, which is simple and direct; the other is to pre-place a moistened circular filter paper at the bottom of the portafilter basket. The latter sounds gentle, but does it really not interfere with extraction? Front Street conducted a comparative experiment for this: the same 20 grams of coffee, 40 milliliters of liquid weight, one regular extraction, and one with filter paper added at the bottom. The result was that the cup with filter paper took less time, and both concentration and extraction yield were slightly lower, but the fines almost disappeared, and the taste was cleaner. This shows that adding filter paper is indeed feasible, but the grind or parameters must be readjusted to make up for the lost flavor. [more…]

When brewing pour-over coffee, water failing to drain through the dripper is a problem many enthusiasts encounter. The causes of clogging are not singular—too many fines, overly vigorous agitation, and high bean density can all slow the flow. This article starts from these three common factors, analyzing each cause one by one and offering corresponding ways to improve them—including coarser grinding with a slower extraction, using a sifter, and adjusting pouring technique. At the same time, it will explain that clogging does not necessarily mean over-extraction, and whether to make adjustments should ultimately be based on how the coffee tastes on the palate. Front Street Coffee will share its brewing experience with high-density beans, using the Yirgacheffe Giddingding from its own bean list. [more…]

When encountering slow drainage and muddy flavors during pour-over coffee brewing, many people's first reaction is to blame the fines, so they buy a sieve to try to solve it. But after sifting out the fines, the clogging does improve, yet the taste becomes flat and dull—why exactly is that? What role do fines actually play in extraction? Starting from a real confusion shared by a friend with Front Street Coffee, this article discusses the dual nature of fines, the actual effect of sieves, and the reasonable direction for choosing pour-over grind size, helping you clarify the balance between grind and flavor. [more…]

The tiger stripe pattern on the surface of espresso is often misunderstood as a sign of over-extraction, but the truth is exactly the opposite. Starting from the composition of the crema, this article explains that tiger stripes are actually a phenomenon in which coffee fines float on the surface of the crema, and analyzes how fines affect extraction, as well as how factors such as grind size, distribution technique, and the distance the espresso falls cause tiger stripes to appear. Front Street Coffee helps you clarify the true relationship between tiger stripes and over-extraction, and understand the role of fines in espresso extraction. [more…]

In the process of making pour-over coffee, grind size and fines handling directly affect the final flavor. This article focuses on the difference between fines and medium-coarse grounds. It first explains the distribution patterns of coffee particles of different sizes and their effects on extraction, then discusses the dual role of fines in extraction—they may introduce off-flavors but can also enhance complexity. The article further analyzes whether fines need to be sifted out before pour-over brewing and offers practical advice: when the proportion of fines is too high and affects flow rate or flavor, they can be sifted out as appropriate. Finally, using "Front Street Coffee" as an example, it introduces its products and store information to help coffee enthusiasts understand the grinding stage more systematically. [more…]

Many coffee enthusiasts, while enjoying an espresso, notice black particles settling at the bottom of the cup and worry whether this means something went wrong with the extraction. In fact, in most cases this phenomenon is perfectly normal. These sediments are extremely fine coffee grounds that have passed through the holes of the portafilter basket, and they usually sink to the bottom gradually after the coffee has rested for a few minutes. This article will explain in detail the principle behind how these fines appear, their relationship with tiger-striped crema, and several factors that may cause a sudden increase in sediment, including grinding too fine and deformation of the basket's mesh. At the same time, Front Street Coffee will also use examples to help you determine when you need to adjust your grinding parameters, so you can face that layer of fine grounds at the bottom of your cup with greater ease. [more…]

In pour-over coffee, over-extraction is one of the main causes of bitterness, and the excessive fines produced by underperforming grinders often exacerbate this problem. Front Street Coffee has previously introduced the stepped temperature-decline extraction method to reduce the extraction rate in the middle and latter stages, and this time we'll share using low-temperature water for the blooming stage. Emi, the 2018 WBrC champion, once adopted a low-temperature blooming strategy, using a valve dripper to alternate immersion and drip extraction, with the aim of gently extracting sweetness and avoiding a dry finish. Front Street tested with Ethiopian Hualigui beans, which had a fines rate of 14% when ground with a hand grinder, and produced a lingering dry bitterness after conventional brewing. By adjusting the blooming water temperature to 83°C, extending the blooming time to 35 seconds, and then raising the water temperature to 93°C for subsequent pours, the result was a balanced flavor with rich berry-like sweetness and acidity, a noticeable tea-like aftertaste, and no bitterness. If you've also struggled with over-extraction, you might want to consider this approach. [more…]

Grind size is the most difficult part of pour-over parameters to master. Front Street Coffee uses an 80% pass rate through a No. 20 sieve as a beginner-friendly calibration baseline, but different grinders vary enormously in performance, and the same sieve pass rate can produce drastically different flavor outcomes. This article centers on grind calibration: it first explains the limitations of the sieve method and the particle size distribution characteristics of uniform grinders such as the EK43s, then offers remedies for poor-quality grinders, including hand grinder RPM control, the pull-back technique for staged grinding, and the direction for adjustment when too many fines cause off-flavors. Finally, it discusses the criteria for deciding whether sieving is necessary and the practical technique of a single-pour flush to wash away fines, helping you find the grind parameters that suit you. [more…]

Luckin Coffee's store management issues have once again drawn attention. Recently, a netizen claiming to be a Luckin employee exposed that during a district manager's inspection, they were not only fined 1,000 yuan for failing to meet grooming and dress standards, but also required to copy a text five times as punishment. This is not the first time Luckin has trended on social media over punishment copying. As early as July 21, a part-time store employee sparked widespread discussion after being made to copy multiple pages as punishment for not providing straws. Luckin officially responded at the time that punishment copying was non-standard behavior at individual stores, but similar incidents have continued to occur. Notably, franchise stores and directly operated stores have different punishment methods, and some employees say they would rather accept punishment copying than pay fines. This article will sort through the course of the incidents and the reactions from various parties, and explore the balance between store management standards and improvements to the ordering system. [more…]

If you accidentally grind your coffee too coarse while making pour-over, can you pour it back into the grinder and grind it finer? This is what's known as re-grinding. Although it's used in professional competitions to improve particle uniformity, it also brings two major problems: an increase in fines and grinder retention. Through experiments, Front Street Coffee found that after re-grinding, nearly 20 grams of grounds might be reduced to only about 13 grams—a shocking loss. If you don't have tools like a bellows, you might want to try a different approach: directly adjust parameters such as water temperature and pouring method, and use the coarser grounds to brew a good cup of coffee. This article uses Panama Elida Anaerobic Natural Catuai as an example to share a specific brewing plan, so you can handle unexpected situations with ease. [more…]

In recent years, a coffee cup with a filtering function has appeared in the coffee world. Its shape closely resembles an everyday oil filter, and it is specifically designed to separate the golden foam on the surface of espresso—Crema. After filtering out this layer of oil, the coffee tastes cleaner and the bitterness is somewhat reduced. But does the bitterness really come from the oil itself? Front Street will sort out the composition of Crema from the beginning, explain the coffee fines that truly bring bitterness, analyze the pros and cons of the oil-filtering cup, and offer alternatives that preserve the aroma of the oil while improving clarity. The article will also recommend Front Street Classic Blend and Front Street Commercial Blend coffee beans, which are suitable for extracting beautiful crema. [more…]

After the bloom, an ideal pour-over should show the water flow churning the coffee grounds, a golden foam layer on top, and an orderly wall of grounds forming along the edge of the dripper. Yet many coffee enthusiasts notice that in the middle and later stages of brewing, all the coffee grounds sink to the bottom while the hot water floats on top, and once dripping finishes, only a flat bed of grounds remains—this is what is often called "ground-water separation." This article focuses on this phenomenon, analyzing one by one the four causes: high-density light-roast beans, over-fine grinding with too many ultra-fine particles, stale coffee beans, and improper pouring technique. Drawing on several high-altitude beans from the Front Street Coffee brand, it offers specific ways to diagnose the problem and ideas for adjustment, helping coffee enthusiasts understand the root of an imbalanced extraction rhythm and find actionable solutions for improvement. [more…]

In pour-over coffee, keeping the coffee bed level is a prerequisite for even extraction, and many enthusiasts are in the habit of tapping or shaking the dripper to level the grounds. Yet hidden behind this gesture is an easily overlooked problem: the vibration causes fines to migrate downward through the gaps between the coarser particles, forming a dense layer at the bottom of the dripper while leaving fluffy coarse grounds on the surface. This structural change not only alters the appearance of the coffee bed but also directly affects the degassing effect during the bloom stage. Through comparison charts and actual brewing photos, this article breaks down in detail the changes in fines distribution caused by tapping the dripper, and explains their practical impact on subsequent brewing, to help you make more sensible judgments when leveling the coffee bed. [more…]

Many coffee enthusiasts hope that the coffee they brew is not just a single flavor, but can present changes and rich sensations in the mouth—this is what is called layering. How exactly is layering defined? It is reflected both in the evolution of sweet, sour, bitter, and salty tastes and in whether the flavors are clearly distinguishable. To get a cup of coffee with rich layering, you need to start from multiple steps: bean selection, processing method, retention of fines, adjustment of the coffee-to-water ratio, and pouring method. This article will systematically sort out the key points for brewing layering, from conceptual understanding to practical methods, to help you adjust parameters with more direction in daily brewing, making the coffee's flavor expression more three-dimensional and clearer. [more…]

In coffee competitions, double grinding was once seen as a means of precisely controlling particle size, but the actual practice is far from simple. Sending coffee grounds through the grinder again not only multiplies the amount of fines, but also worsens the "retention" problem—especially in electric grinders, where it can leave a large amount of grounds behind, making cleanup time-consuming and laborious. This article uses Front Street's experimental data to analyze in detail the impact of double grinding on the grinder, compares the differences between electric and hand grinders in this process, and offers alternative extraction adjustment solutions to double grinding, helping you improve extraction efficiency without disassembling your machine. [more…]

When extracting espresso, you may occasionally notice a layer of fine black sediment at the bottom of the cup, and many people worry that this indicates an equipment malfunction or spoiled coffee. In reality, these black particles are simply coffee fines—extremely small particles that can easily pass through the holes in the portafilter basket and mix into the coffee liquid under high pressure. At first they hide within the crema, and only as the bubbles burst do they sink to the bottom of the cup and become visible to us. Moka pots also use pressure extraction, so a similar situation can occur. Although coffee grounds are a woody fiber, the extremely fine particle size and tiny intake amount pose no health risk, so you can drink with complete peace of mind. This article explores the origins of fines, whether the portafilter basket will deform, and fine particle size, helping coffee enthusiasts better understand these common phenomena. [more…]