In coffee-making, some people wonder: since soaking and stirring are a hassle, why not add ingredients directly into the extraction process and let the hot water bring out the flavors along with it. For most brewing methods, this can indeed simplify the process and blend the flavors, but Front Street Coffee explicitly does not recommend using it for espresso. The reason is that espresso extraction relies on about 9 bar of pressure, with a 58mm puck bearing roughly 240 kilograms of force, making extraction extremely efficient and extremely sensitive. Once the puck's structure is disrupted by foreign objects, hot water will preferentially flow along the path of least resistance, forming channeling, which causes some coffee grounds to be over-extracted and others under-extracted, resulting in an imbalanced flavor. This article starts from the principles of pressure extraction and the relationship between Fick's law and grind size, and combines experiments and cases such as adding sugar and adding butter to explain why espresso should not be mixed with other materials, as well as safer ways to add flavor when desired. [more…]

The extraction quality of espresso can be judged not only by flow rate, pressure, and time—the puck after extraction also reveals a great deal of key information. An ideal puck should be dry and level, structurally intact, and uniform in color. In practice, however, problems such as cratered surfaces, holes, standing water, loose structure, one half dry and the other half wet, or even a blackened bottom are all too common, and they often point to deviations in dose, grind size, distribution technique, or equipment pressure. This article systematically sorts out the manifestations and causes of six common puck abnormalities, offers targeted adjustment plans, and explains how to correct extraction through operations such as grinding finer while reducing dose, or grinding coarser while increasing dose, helping coffee enthusiasts consistently make a qualified espresso at home. [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…]

When ordering an espresso at a coffee shop, you can ask for a single shot or a double shot. On the surface, single and double espressos differ only in volume, but from the barista's operational perspective, this involves two completely different extraction schemes. Portafilter basket capacity, puck structure, and uniformity of pressure distribution can all create noticeable differences in the final product. This article starts from Front Street Coffee's extraction experiments, using specific data to compare the extraction performance of single baskets versus double baskets, explaining why a single espresso is not simply half of a double, and includes a standard double espresso preparation procedure to help you gain a deeper understanding of the intricacies behind this small cup of coffee. [more…]

During the espresso extraction process, channeling is a common problem encountered by many coffee enthusiasts. When the internal structure of the coffee puck is uneven, pressurized hot water will preferentially pass through the areas of least resistance, forming perforations and spurts, which leads to uneven extraction and imbalanced flavor. This article will systematically review the causes of channeling and approaches to address it from the perspectives of distribution and tamping techniques, dose control, grind size adjustment, and dispersion screen cleaning, helping you more accurately identify the source of the problem when using a bottomless portafilter or a spouted portafilter, and improve the extraction stability and taste performance of your espresso. [more…]

We often hear experienced coffee enthusiasts or bloggers say something like this: "Master your puck bed management, and your pour-over coffee will taste better!" Some friends find this quite puzzling! Since they've just started out, they haven't even had the chance to figure out what exactly a puck bed is, let alone manage it. [more…]

If you mistakenly press the stop button during espresso extraction before reaching the target yield, can you simply press it again to continue extraction? This article compares three espressos—normal extraction, mid-extraction stop-start, and stop-start near the final phase—to analyze how segmented extraction affects the color, flavor, and concentration of the coffee liquid. Front Street Coffee uses the Warm Sun blend, testing with 20g of grounds extracted to 40ml at a 1:2 brew ratio, to reveal why under pressurized extraction, changes in the puck structure cause an overly fast flow rate and under-extraction during a second extraction, along with operational recommendations. [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…]

Crafting a perfect espresso is the goal of many coffee enthusiasts. However, in practice, sudden spurting, pinholes, or channeling in the espresso flow often catch people off guard. These phenomena not only affect the uniformity of coffee extraction, but also lead to weakened aroma, a thinner mouthfeel, and even unpleasant flavors such as sharp acidity and bitter burnt notes. This article will take an in-depth look at the causes of channeling, from dosing details, portafilter knocking, dose control, to coffee grounds clumping and more, helping you find the root of the problem and offering practical solutions. At the same time, we will also discuss whether a split portafilter can truly solve channeling issues, and share Front Street Coffee's classic espresso blend recommendation to help you easily improve the quality of your espresso. [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…]

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…]

When ordering at a coffee shop, have you ever noticed the filter basket the barista uses? A single basket typically holds 9–11g of coffee grounds for pulling a single espresso; a double basket can hold 18–22g for a double espresso. But in reality, most cafés would rather use a double basket to pull an extra shot—even pouring half of it down the drain—than switch to a single basket. Why is that? Starting from Front Street's comparative experiments, this article takes a deep dive into the structural differences, extraction performance, and consistency issues of the two baskets, helping you fully understand which basket a single espresso should actually use. [more…]

Recently, a compact metal accessory has been generating quite a bit of discussion in the coffee community. Many enthusiasts see it as a handy tool for simplifying the extraction process—the secondary dispersion screen. What changes can this metal disc actually bring? Can it truly solve the common problem of wet, crumbly pucks after espresso extraction? In this issue, Front Street will analyze the core functions of the secondary dispersion screen, and combine that with hands-on experience using related products from the Bomber brand to provide an objective reference for coffee lovers who are still on the fence. [more…]

When extracting espresso, many coffee enthusiasts strive to knock out a complete puck. Although whether the puck is complete does not directly determine the flavor of the coffee, it can indirectly reflect whether the extraction process is standardized. The formation of the puck is closely related to operations such as distribution and tamping, and these steps are precisely the key to affecting coffee quality. Based on the practical experience of Front Street Coffee, this article explains in detail how to reduce channeling by choosing an appropriate dose, distributing the grounds evenly, and tamping correctly, ultimately obtaining a complete puck and thereby increasing the chances of making delicious coffee. [more…]

When pulling espresso, you sometimes remove the portafilter and find a large amount of hot water left in the basket, with the puck wet, even loose and misshapen. This phenomenon not only affects consistency in the cup but also makes it hard to identify the root cause. Starting from the principles of espresso extraction and pressure release, this article systematically breaks down the three common causes of water pooling in the basket: grinding too fine, which impedes the flow of hot water through the coffee bed; using too small a dose, which leaves too much distance between the puck and the shower screen; and insufficient pressure on home machines, which weakens the back-suction effect. It also offers Front Street Coffee's adjustment suggestions to help coffee enthusiasts quickly pinpoint the problem and improve extraction flow rate and puck condition. [more…]

Espresso is the core of café output and the litmus test of a barista's fundamental skills. This article begins with the definition of espresso and its three major structures, explains the formation principle of the crema, clarifies why espresso production favors fresh medium-dark roasted beans, and offers recommendations for two Front Street Coffee espresso blends; it then provides a complete breakdown of the six-step process from cleaning the portafilter basket, grinding and dosing, distributing the grounds, tamping, locking in the portafilter and extracting, to cleaning. Whether you want to understand espresso flavor or want to consistently replicate a qualified espresso at home, this article will give you clear answers. [more…]

When pulling espresso shots, have you ever encountered water pooling in the portafilter basket, a loose puck that won't hold its shape, or crema that clumps up quickly with tiger stripes appearing on the surface? Each of these phenomena actually has its own underlying cause. This article continues Front Street's series on common espresso extraction issues, breaking down key variables one by one—dose, grind size, coffee bean degassing, and fines distribution. From judging extraction evenness by puck condition, to understanding the relationship between crema clumping and coffee bean freshness, to clarifying whether tiger stripes really mean over-extraction, this guide helps you troubleshoot more accurately and adjust your parameters, making every espresso shot more stable and controllable. [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…]

How much coffee grounds should you use when making espresso? What is the difference between single and double baskets? Drawing on Front Street Coffee's hands-on experience, this article provides a detailed analysis of the structural characteristics and current usage of single-shot espresso baskets, explaining why double baskets have become the mainstream choice. At the same time, using "Front Street Sunflower · Warm Sun Espresso Blend Coffee Beans" as an example, it fully demonstrates the standard extraction process for a double basket, covering dose, yield, time control, and distribution and tamping techniques, to help you consistently produce an espresso with thick, velvety crema and rich, layered flavors. [more…]

Espresso is known for its thick crema, rich body, and intense sweet aftertaste, but many people are also curious: why do some espressos taste sour? What kind of person is it really suitable for? This article will start with Espresso's three-layer structure—crema, body, and heart—to clearly explain its flavor and mouthfeel characteristics, and further explain the key points for making a good-tasting espresso, extraction parameters, and tasting methods. The article also retains Front Street Coffee's specific recommendations on bean resting, serving parameters, and blend beans, helping coffee enthusiasts understand this small cup of espresso more systematically. [more…]