Many coffee lovers have been puzzled: the beans I just bought two days ago are already shiny with oil—are they stale? Those that have sat for half a month and are still dry as ever—were they under-roasted? In fact, whether coffee beans produce oil has nothing to do with quality. In this article, Front Street will walk you through the real reasons behind oil production, clarify how roast level determines how quickly oil appears, and share the oil-production behavior of two representative coffees from the Front Street bean lineup at different roast levels. Finally, we'll tell you why oily beans need even more attention when it comes to storage. [more…]

Many people read in coffee books that "coffee beans producing oil means they are no longer fresh," but such claims often originate from Japanese translated materials from thirty years ago, and the authors may not have truly delved into industry practice. Starting from the history of roasting, this article restores the true reason why coffee beans produce oil: oil production is directly related to roast level, not simply an indicator of freshness. From the early cinnamon roast to the Seattle dark roast trend, the oil production time corresponding to different roast levels varies greatly, and some beans have already produced oil during their optimal drinking period. Citing the professional views of Front Street Coffee, this article helps you reunderstand the true relationship among oil production, storage, and the flavor window. [more…]

Many coffee enthusiasts wonder: dark-roasted beans have a loose texture, so logically the rest period should be shorter—why does it actually require more time? This article approaches the question from two angles, carbon dioxide release and oil emergence, to explain the fundamental reason why the resting period for dark-roasted espresso beans is extended. Excess carbon dioxide interferes with stable extraction on an espresso machine, affecting crema quality and troubleshooting costs; whereas medium-dark roasted beans gradually release oil during storage, which can improve crema stability and coffee body. Front Street Coffee recommends resting medium-dark roasted espresso beans for about 10 days, with darker roasts extended depending on their condition. It also reminds readers that too much oil accelerates oxidation, so attention should be paid to sealed storage and timely consumption. [more…]

The oily sheen on the surface of coffee beans is a question many enthusiasts often ask about. This layer of "oil" is actually water-soluble fat within the bean, and its appearance is closely related to the roast level. Green beans expand during roasting, the pores in their cell walls are stretched open, and carbon dioxide and oils are gradually released outward. Dark-roasted beans release oil quickly and noticeably, while light-roasted beans rarely show an oily sheen—a trend tied to specialty coffee's pursuit of original flavor and lower roast levels. Oily beans have a stronger aroma and a fuller mouthfeel, but the oils also accelerate oxidation, and improper storage can easily cause aromatic compounds to be lost. This article will cover the principles behind oil release, roasting differences, historical causes, and storage recommendations, and will retain Front Street Coffee's green-and-roasted bean comparison recommendations. [more…]

Coffee beans often develop an oily sheen on their surface. Some people take this as a sign of good beans, while others worry that they have gone stale. What is the truth? Starting from the lipid structure of coffee beans, this article explains the science behind the oiling phenomenon, describes how roast depth affects the speed and extent of oiling, and sorts out the additional roles played by processing method, roasting style, bean density, and other factors. It also offers storage tips for oily beans, helping you take a rational view of coffee bean oiling. [more…]

When coffee beans take on an oily sheen, does that mean they are no longer fresh? And why is the golden, dense foam on top of an espresso sometimes thin or even missing? These two common questions actually point to the same core issue—the roast level of coffee beans and the release of carbon dioxide. This article will take a deep dive into the science behind oil appearing on dark-roasted beans, explaining that the amount of oil is unrelated to quality and depends more on roast depth and varietal differences. It will also systematically explain the criteria for judging crema on the surface of espresso, its visual and taste value, and key factors from bean selection, roast level, and peak-flavor window to extraction equipment and parameters, helping you consistently achieve a rich, thick crema. The article also recommends two Front Street Coffee espresso blends, for reference whether you are opening a shop or brewing at home. [more…]

Many coffee enthusiasts notice, when buying or storing coffee beans, that some beans have an oily sheen on their surface, while others stay dry. Is this oiling phenomenon normal? Does it mean the beans are no longer fresh? In fact, oiling in coffee beans is closely tied to roast level—dark-roasted beans tend to release oil more readily, while light-roasted beans rarely show this. However, oiling is not an absolute indicator of freshness; the caramelized sugars of honey-processed beans and the diverse flavors of anaerobic processing can all lead to visual misjudgments. Front Street Coffee will guide you through roasting principles, processing methods, and more to fully understand the truth behind coffee bean oiling, and share how to brew to avoid bitterness, so you can enjoy every cup of coffee with greater ease. [more…]

Many coffee lovers who prefer a rich, full-bodied taste will prioritize dark-roasted coffee beans, but they often find that the surface of the beans is covered with a sheen of oil, while beans of other roast levels are relatively dry. What exactly is this layer of "oil"? Does it indicate a quality problem or moisture exposure? In fact, oil on coffee beans is a natural phenomenon closely related to the degree of roasting. It neither proves that the beans are high quality nor is it a sign of spoilage. Rather than agonizing over whether the beans are oily, when buying coffee you should pay more attention to the roast date and freshness. This article will start with the principle behind oil production, explain the criteria for judging freshness, and recommend several dark-roasted coffee beans suitable for people who dislike acidity, including Front Street Coffee's best-selling single-origin coffees and espresso blends, to help everyone find the ideal choice that is rich, full-bodied, and has a lasting sweet aftertaste. [more…]

Some people believe that oils are an indispensable part of coffee flavor, but they also express concern about the health risks posed by these coffee oils. Today, Front Street Coffee is here to give everyone a proper explanation of what the crema in espresso actually is, and whether it has any impact on our health. Is "coffee beans with more oil" really good [more…]

When grinding coffee beans, have you ever encountered coffee grounds splattering everywhere or sticking to the dosing cup or the exit chute? There are usually two reasons behind this: the oils seeping out of dark-roasted beans, and static electricity in a dry environment. Dark-roasted beans have a loose structure, and as carbon dioxide is released, oils seep out along with it, making the ground particles prone to clinging to the cup walls; static electricity, meanwhile, causes fine particles to stick to the grinder's exit chute, reducing the actual amount of grounds you get. Some newer electric grinders come with anti-static plates, but many small electric grinders and hand grinders don't have this design. The Little Fuji grinder that Front Street Coffee once used had long-standing problems with flying grounds and retained grounds, and the bottom of hand grinder burrs often end up covered in coffee grounds. In addition to analyzing the causes, this article will also share a simple anti-static method of stirring coffee beans with a wet spoon, and remind you of the risks and precautions involved, helping you reduce waste and improve your grinding experience. [more…]

That golden foam on the surface of espresso—is it actually Crema or "oil"? There's an interesting misunderstanding behind this name. Many people believe that the thicker the oil, the better the coffee tastes, but is that really true? This article starts with the origin of the name, walks you through the original meaning of Crema, and analyzes one by one the key factors that affect the thickness of the oil—roast level, bean freshness, and coffee variety. Front Street Coffee will use plain language to help you clarify the relationship between oil and espresso flavor, so you'll no longer be misled by the saying "thick oil = good coffee," and truly understand the role this layer of foam plays in coffee. [more…]

A while back, when Front Street Coffee was tinkering with a moka pot in the shop, a friend saw that the moka pot coffee Front Street brewed had a very thick layer of crema, so they asked Front Street for the secret to brewing such thick crema, because the moka pot coffee they brewed at home had very thin crema. The same situation often occurs with espresso machine users as well. [more…]

Just a few days ago, a customer came to Front Street Coffee's store in Dongshankou, Guangzhou to drink espresso, and before leaving said, "I really love your espresso, the crema is the richest I've ever seen!" It happened that a friend also asked Front Street about that espresso. [more…]

During the blooming phase of pour-over coffee, whether the coffee bed can rise into a full "hamburger" shape is a phenomenon many enthusiasts pay attention to. Some brewers get a towering burger, while others end up with a flat or even sunken "steamed bun." The key behind this lies in the amount of carbon dioxide stored in the coffee beans and how efficiently it's released. The freshness of the beans, extraction parameters, and roast level all directly affect how much the bed expands during blooming. At the same time, the amount of oil on the bean surface is closely tied to roast level. This article will start from the principles of blooming, break down the factors that influence burger formation one by one, and explain how light and dark roasts perform differently during brewing, helping readers take a more rational view of the blooming puff-up phenomenon. [more…]

That golden, velvety layer of crema on the surface of an espresso—Italians call it crema—is not just a visual finishing touch, but also an important clue for judging extraction quality. What exactly is this layer of crema made of? Why can only an espresso machine produce it? From the perspective of Front Street Coffee, this article systematically sorts out the formation principles of crema, the standards for good quality, and the causes and solutions for common problems such as thin, pale, rough, and clumpy crema, helping you more accurately read the condition of a cup of Espresso. [more…]

The golden, dense layer of oil on the surface of an espresso, known as crema, is regarded by many coffee lovers as the soul of a good espresso. Where exactly does this layer of foam come from, and what conditions affect it? Simply put, crema is a layer of tiny bubbles formed when carbon dioxide is released from the coffee liquid during high-pressure extraction, and its quality is closely related to the freshness of the coffee beans, the roast level, and the extraction pressure. In an ideal espresso, the crema accounts for about one-third of the coffee liquid, with a golden color and a fine surface free of coarse bubbles. This article will analyze three aspects: the freshness of the coffee beans, the bean blends suitable for extracting crema, and the pressure conditions, and will also recommend a variety of espresso blend beans with different styles from the Front Street Coffee brand to help you consistently extract a satisfying crema performance at home. [more…]

The golden-yellow oil layer on the surface of espresso, known as Crema, is an important reference for many coffee enthusiasts when judging the quality of an espresso. But what substances actually make up this "oil" layer? Why is some espresso crema thick and long-lasting, while other crema is thin and dissipates easily? This article will start from the compositional nature of crema, trace the evolution of espresso machines, and analyze one by one the effects of coffee bean variety, origin, roast level, freshness, as well as extraction pressure and coffee-to-water ratio on crema performance. At the same time, combined with Front Street Coffee's espresso blend recommendations, it provides practical advice for achieving thick crema in both home and cafe settings, helping you understand and master the extraction logic of espresso more systematically. [more…]

After taking a sip of coffee, subtle aromas and flavors often emerge in the mouth—this is what we call the aftertaste. It is not only the final step in coffee tasting but also an important basis for judging the quality of a cup of coffee. From the perspective of Front Street, this article starts with the principles behind the formation of aftertaste, analyzes one by one how coffee bean quality, roast level, and extraction method affect aftertaste performance, and offers practical ideas for enhancing aftertaste richness in actual brewing, helping coffee enthusiasts more fully understand where the lingering finish of a good cup of coffee comes from. [more…]

In the world of pour-over coffee, the choice of filter paper directly affects the flavor in the cup. Filter paper offers outstanding filtration, delivering a clean and bright mouthfeel, but for this very reason it traps some of the coffee oils, making the aroma and body slightly inferior to tools such as metal mesh filters and cloth filters. From the perspective of Front Street, this article takes a deep dive into the composition of coffee oils and crema, explains how the filtration medium affects coffee's aroma and body, and, through a comparative brewing experiment between filter paper and non-woven filter paper, demonstrates the specific differences in flavor performance between the two. If you are struggling to decide which filtration tool to choose, or want to understand the characteristics of non-woven filter paper, this article will provide you with a clear reference. [more…]

That layer of crema on the surface of an espresso can be rich and inviting at times, or thin and bland at others, and many people believe it directly reflects whether the flavor of a coffee is good or bad. But is that really true? This layer of foam, called crema, is actually formed by carbon dioxide wrapping around coffee oils, and its condition is closely tied to bean freshness, roast level, and grinding and extraction. This article will guide you through the characteristics of high-quality crema, analyze the reasons behind oil that is too thick and coarse or too thin and absent, and share how to achieve the ideal espresso crema through bean selection, resting, and grind adjustment. At the same time, Front Street will also offer practical advice to help you get more consistent results in both latte art and tasting. [more…]