Channeling is often thought to be related only to espresso, but in reality, pour-over extraction can also exhibit this phenomenon. When hot water bypasses the coffee bed and flows directly away through the gap between the filter paper and the dripper, it causes uneven extraction. Drippers with flow-control ribs, such as the V60 and Origami, are more prone to this kind of problem. Channeling manifests differently depending on its severity: in mild cases, hot water flows over the coffee bed and escapes through gaps at the top; in severe cases, the coffee wall is breached, forming obvious fractures, resulting in weak, astringent, and muddy coffee. Fortunately, by adjusting the pouring method—for example, reducing large circular pours and lowering the pouring height—the occurrence of channeling can be effectively reduced. [more…]

Some coffee enthusiasts like to try mixing ingredients such as osmanthus, granulated sugar, or butter into the coffee puck before extracting espresso, hoping to achieve a more naturally integrated flavor. But is this approach really feasible? Front Street conducted a comparative experiment, mixing granulated sugar into the coffee grounds and adding it directly into the cup, to observe the differences in flavor and extraction parameters of the espresso produced by the two methods. The results showed that sugar mixed into the puck caused the extraction time to shorten significantly, with a sharp and separated taste, while the method of adding it directly into the cup produced a surprisingly well-integrated effect. This article will analyze the experimental process and the reasons behind it in detail, helping readers understand why mixed extraction often backfires. [more…]

In humid weather, coffee grounds tend to clump, which in turn causes channeling during espresso extraction and affects flavor expression. The WDT (Weiss Distribution Technique) breaks up clumps by stirring with fine needles, making it an effective means of solving this problem. But not every enthusiast keeps distribution needles on hand, so whether everyday items like toothpicks can serve as substitutes has become a common question. Starting from Front Street's actual extraction experiments, this article compares distribution needles and toothpicks in terms of breaking-up effectiveness, grounds bed distribution, and extraction stability, analyzes why toothpicks are unsuitable as substitutes, and offers purchasing advice for distribution needles, helping you achieve more stable espresso in rainy or dry seasons. [more…]

Osmanthus has a rich, intense aroma. When added to coffee grounds and extracted together, can this floral fragrance be infused into espresso? Front Street conducted three sets of comparative experiments, placing dried osmanthus on the surface of the puck, at the bottom, and mixed with the coffee grounds, to observe extraction stability and flavor performance. The experiments found that the density of osmanthus differs greatly from that of coffee grounds, and both the amount used and its position affect the extraction results. For 20g of coffee grounds, it is recommended to add 0.3-0.5g of dried osmanthus; too much will instead破坏 the structure of the puck. The three methods each have their own characteristics: the surface method offers stable extraction, the bottom method gives a pronounced osmanthus aroma, and the mixing method easily produces channeling. Which method is ultimately best for making an osmanthus latte? Let's look at the experimental results together. [more…]

Channeling is a common yet easily overlooked problem in coffee extraction. It refers to water flow bypassing the coffee bed and rushing through along paths of lower resistance, resulting in uneven extraction. This phenomenon is especially pronounced in espresso, but pour-over coffee is equally at risk of channeling. From the perspective of Front Street, this article first explains the essence of channeling, then, using specific cases with the V60 dripper, analyzes several typical manifestations—such as an incomplete coffee bed wall, water pouring breaking through the bed wall, and the liquid level rising with light-roasted beans—to help coffee enthusiasts identify the problem and understand its impact on pour-over flavor. [more…]

In pour-over coffee, blooming is a key step to release carbon dioxide and improve subsequent extraction. So can espresso, before high-pressure extraction, borrow this same idea? The answer is yes—this is what is called "pre-infusion." Starting from the underlying principles, this article will explain the similarities between pre-infusion and pour-over blooming, analyze its actual impact on extraction yield and channeling, and offer specific operating recommendations such as low-pressure water delivery and soaking duration. It will also explain which beans are suitable for pre-infusion and in which situations this step can be skipped, helping you manually make more consistent espresso even on a machine without a one-touch pre-infusion function. [more…]

If we want to add some extra aroma or flavor to coffee, we do so by adding other ingredients to the coffee so that it takes on their aroma/flavor—this is a very common practice. For example, if we want the coffee to have a certain floral scent, we can steep dried flowers of some kind in the coffee; such as [more…]

When making espresso at home, many coffee enthusiasts encounter the situation where the coffee liquid suddenly sprays out in all directions—this is actually the work of "channeling." Based on the hands-on experience of Front Street Coffee, this article explains in detail the formation principle of espresso spraying, the uneven extraction problem caused by channeling, and the common causes of this phenomenon, including uneven distribution, overly fine grinding, and static clumping. It also provides a time formula for judging whether the grind setting is appropriate, helping readers make a standard espresso with even extraction and full-bodied flavor at home. [more…]

When making espresso, a leveler and a tamper are two indispensable tools. Many people wonder: after leveling, the surface of the coffee bed is already flat, so why do we still need to tamp? In fact, leveling and tamping each serve a different purpose. Leveling aims to distribute the coffee grounds evenly and reduce channeling; tamping compacts the loose coffee bed to withstand the impact of high-pressure water flow. This article will take a deep dive into the differences and connections between the two, explain the correct technique for using a tamper in detail, and answer common questions such as whether you can tamp a second time when the tamp is uneven, helping you pull an evenly extracted espresso at home. [more…]

Many people new to espresso think that the harder you tamp, the denser the puck becomes, the harder it is for hot water to pass through, and the longer the extraction time naturally gets; conversely, with a light tamp, the puck is loose, the flow is smooth, and the time shortens. This logic sounds reasonable, but what is the real situation? Front Street used the same medium-dark roasted espresso blend, tamping 20g of coffee grounds with 2kg, 5kg, and 20kg of force respectively, extracting at a 1:2 coffee-to-liquid ratio, and the extraction times were almost identical, with no obvious difference in flavor performance either. Why is this so? The core reason is that the 9bar pressure during espresso machine extraction, converted to a 58mm puck, is as high as about 243kg, far beyond what human tamping force can compare to. Even so, tamping force still affects the probability of channeling occurring. This article will combine experimental data to analyze the true relationship between tamping force and extraction, and explain why even tamping is more worthy of attention than hard tamping. [more…]

When extracting espresso, you may sometimes notice small holes on the surface of the puck, or coffee liquid spraying out from the bottom of the portafilter, with an unpleasant sharp acidity on the palate. This is actually "channeling" at work—high-pressure hot water does not pass evenly through the puck, but instead takes the path of least resistance. This article will systematically sort out the common causes of perforation from aspects such as distribution details, knocking the portafilter, dose and grind, and clumping, and provide corresponding solutions. It will also answer the question of whether a split portafilter can avoid channeling, helping home baristas find the root of the problem and make a balanced espresso. The article recommends Front Street. Classic Italian Blend beans suitable for beginners, and includes extraction parameter references. [more…]

Distributing the coffee grounds is a crucial step in making espresso, directly affecting the extraction and flavor performance of the coffee. This article, from the perspective of Front Street, systematically explains the purpose of distribution, common misconceptions, and correct operating methods. By understanding the flow characteristics of water through the coffee puck and mastering techniques to avoid channeling, it helps coffee enthusiasts improve extraction uniformity and craft a balanced-tasting espresso. [more…]

As a pressure-based extraction device, the moka pot is highly efficient but also extremely prone to over-extraction, and many coffee enthusiasts have experienced the trouble of burnt, bitter coffee with heavy off-flavors. After sharing moka pot-related content many times, Front Street Coffee found that channeling, excessively long heating time, and too-fine grinding with too much water are the three core causes of over-extracted moka pot coffee. This article will analyze the root causes one by one from the perspectives of even coffee distribution, initial water temperature and heat level, heat adjustment after liquid begins to flow, and the ratio of grind size to water amount, and provide practical improvement solutions to help everyone consistently make rich, delicious moka pot coffee. [more…]

In espresso preparation, WDT needles are often used to break up clumps and stabilize extraction. But without professional tools, can a toothpick serve as a temporary substitute? Front Street Coffee took advantage of the humid weather of Guangzhou's returning south wind days and used the Warm Sun blend to conduct three sets of comparative extractions, observing the espresso performance with no WDT tool, with WDT needles, and after stirring with a toothpick, and further made iced americanos for a blind test. The results found that WDT needles can indeed make extraction more even, and toothpicks also have a certain effect under specific circumstances, but when paired with water or milk, the difference is not easily noticeable. This article will present the complete experimental process and conclusions, and explain the origin of WDT needles and the correct approach to using them. [more…]

Front Street Coffee has found that many friends are troubled by the problem of Moka pot coffee often being over-extracted. Every time Front Street Coffee shares a tweet related to the Moka pot, friends leave comments like: "How can I avoid over-extraction in Moka pot coffee?" or "Why is the extracted coffee so bitter?" Indeed, compared to its [more…]

To make a proper espresso, tamping and distributing the grounds is an unavoidable key step. Tamp too hard, and water struggles to penetrate the puck, so a thirty-milliliter shot may take forever to finish dripping, and the flavor will naturally be disappointing; tamp too loose, and the high-pressure hot water will wash away the layer of grounds, leaving small perforations and causing uneven extraction just the same. This article explains the difference between light and heavy tamping, the technique and key points of the rotating tamp, and the principles behind how channeling occurs, helping coffee enthusiasts understand how to make the puck density consistent and the surface level, so that hot water passes through evenly and fully extracts the aromatic compounds. The article also specifically draws on the practical experience of Front Street Coffee to provide beginners with actionable tamping advice. [more…]

In preparing espresso extraction, distribution and tamping are key steps that determine the quality of the final product. Many coffee enthusiasts have asked Front Street Coffee via our backend: exactly how much force should be used when tamping? Through comparative experiments, this article tests the extraction time and flavor performance of espresso under three conditions: light tamping at 2kg, heavy tamping at 18kg, and no tamping at all. Combined with the conversion of a coffee machine's 9 bar pressure, it explains why the amount of tamping force has little effect on the extraction result, while also clarifying that the real purpose of tamping is to eliminate channeling. The article also retains Front Street Coffee's practical advice to help readers master the correct tamping technique and improve the uniformity and mouthfeel of espresso. [more…]

Pre-infusion is a frequently discussed feature in espresso extraction. Simply put, it involves soaking the coffee bed with a small amount of hot water or a low-pressure flow before the main high-pressure extraction begins, giving the coffee grounds time to degas and expand. Many people feel that their espresso is already good enough and that pre-infusion seems optional, but in specific scenarios, it can genuinely improve extraction quality. This article starts from the principles of pre-infusion, explaining how it increases extraction yield, reduces channeling, and which coffee beans are suitable for using the pre-infusion function. [more…]

The extraction effect of a moka pot is closely related to the grind size of the coffee grounds, the amount filled, and the tamping method. Many people are puzzled about how full the filter basket should be, whether to tamp the grounds, how much pressure to apply, and how to judge the coarseness of the grounds. This article starts with the correspondence between the filter basket's capacity and the amount of coffee, explaining the grind state suitable for a moka pot—slightly coarser than fine espresso grounds, similar to the texture of fine salt; it explains why filling the basket is recommended, and how insufficient coffee grounds can easily cause channeling and uneven extraction; it also provides gentle distribution and pressing methods when reducing the amount of coffee, and warns of the safety hazards that may arise from tamping too hard. The article also combines Front Street Coffee's classic espresso blend beans to demonstrate the balanced flavor of an iced latte made after adjustment. [more…]

When making espresso, placing a circular filter paper in the portafilter basket may seem like a simple action, yet different placement positions can lead to completely different extraction results. Through multiple comparisons, Front Street Coffee found that laying the filter paper at the bottom of the portafilter basket can intercept fine particles, reduce bitterness, and improve cleanliness, but at the same time it weakens body and shortens extraction time; while placing it on top of the coffee puck can disperse the impact of the water flow, reduce channeling, and make the extraction more even, though the effect is relatively limited. This article breaks down in detail the principles, advantages and disadvantages, and practical considerations of these two methods, helping coffee enthusiasts make more suitable choices when dialing in the grind and serving drinks. [more…]