Many coffee enthusiasts notice, when tasting pour-over, cold brew, or siphon coffee, that a faint layer of "oil" surfaces as the coffee cools. This is not a sign of spoilage, nor an external impurity, but rather an oily component that coffee itself contains—one that only becomes visible to the naked eye under specific conditions. To understand this phenomenon, we need to start with the composition of Crema, that golden foam atop espresso—it is formed by coffee bean oils wrapping around carbon dioxide. And the key driver that turns oils from "invisible" to "visible" is condensation. This article explains the principle of condensation and how differences in the performance of filtration devices affect the degree of oil seepage, helping readers make sense of this sheen of oil that emerges after cooling. [more…]

A freshly brewed pour-over coffee is full of aroma and smooth on the palate, but after sitting for half an hour it turns sour, astringent, and muddled—what's going on? In fact, coffee naturally presents different flavors at different temperatures, and during tasting it is often divided into three stages: hot, medium, and cool. A good cup of coffee can usually withstand all three temperature stages, but once it has fully cooled, the flavor goes beyond the normal tasting range. From Front Street's perspective, this article breaks down the root causes of coffee turning sour and developing astringent, muddled notes after cooling—including differences in how human senses perceive sourness, sweetness, and bitterness, the impact of aroma volatilization, and the three key mechanisms of oil oxidation, pigment oxidative polymerization, and condensation—and tells you the most suitable temperature for drinking coffee, helping you better capture the best flavor of every cup. [more…]

What should you do if you buy too many coffee beans and can't finish them within their peak flavor window? The aroma of coffee dissipates along with carbon dioxide, so the brewed flavor naturally suffers. Some people therefore try putting their beans in the freezer, said to extend freshness—but does this method actually work? Low temperatures can indeed slow the loss of aroma, but freezing is not foolproof: improper sealing leads to odor transfer, and condensation strikes when you take the beans out. This article walks through the key points and common pitfalls of freezing coffee beans in detail, helping you decide whether this practice is worth trying. [more…]

Many coffee enthusiasts encounter a phenomenon when tasting pour-over coffee: as the temperature drops, the flavor of the coffee seems to change, sometimes even developing an unpleasant sourness. This is not a problem with brewing technique, but rather a series of physical and chemical changes that coffee undergoes as it goes from hot to cold. Front Street Coffee will take you on an in-depth look at the processes of aroma loss, oil oxidation, pigment polymerization, and condensation after coffee cools, while also explaining from the perspective of sensory science why the perception of sourness, sweetness, and bitterness on the taste buds changes with temperature. Through this article, you will understand the real reasons why coffee becomes sour or bitter after it cools, allowing you to view the relationship between coffee temperature and flavor more rationally and improve your tasting experience. [more…]

Cold brew coffee, with its advantages of simple operation and low cost, has become the go-to choice at home for many coffee enthusiasts. All you need is an airtight container and a low-temperature environment, and after several hours of steeping, you get a full-flavored iced coffee drink. However, many people discover during the process that a layer of oil often floats on the surface of the cold brew liquid, and can't help but wonder whether it has spoiled or the equipment is unclean. Where exactly does this layer of oil come from? And how should it be handled to achieve a clearer taste? This article will provide a detailed explanation of the extraction principles of cold brew, the phenomenon of oil condensation, the selection of filtration equipment, and ways to optimize the drinking experience, while also recommending several coffee beans suitable for making cold brew, helping you easily make a clean, translucent, and outstandingly flavorful cup of cold brew coffee at home. [more…]

Cold brew coffee, with its advantages of simple operation and low cost, has become the preferred way for many coffee enthusiasts to make iced drinks at home. However, many people find in practice that a layer of oil slick unexpectedly floats on the surface of a finished pot of cold brew, and they can't help worrying that the coffee has gone bad or the container was not cleaned properly. Where exactly does this layer of oil come from? In fact, its cause is completely different from that of the Crema on the surface of espresso. This article will focus on the low-temperature extraction principle of cold brew, explain the phenomenon of oil condensation, and share the complete operational details from filter selection to secondary filtration, helping you make a cup of cold brew coffee with a clear mouthfeel and full flavor. [more…]

Many coffee enthusiasts notice that when brewing light-roast coffee, it is rich in aroma and stands out with fruity sweetness right after brewing, but as the temperature drops, the sourness becomes especially pronounced. Is this phenomenon normal? What sensory and chemical reasons lie behind it? Front Street Coffee will analyze this from two dimensions: the patterns of human taste perception and the changes in coffee's own components, explaining the differences in how bitterness, sweetness, and sourness are perceived at different temperatures, as well as the impact of aroma volatilization on the flavor experience. At the same time, the article will also discuss the time windows for tasting at high, medium, and low temperatures, and explain the bitterness and astringency caused by the release of tannic acid, helping you fully experience a cup of coffee's flavor layers within the optimal period. [more…]

Every part of the world has its own distinctive coffee equipment; some, though not invented locally, have been perfected there. Ethiopia has the ceramic coffee pot, Turkey has the ceaselessly bubbling cezve, Italy has the moka pot, and Vietnam, with its "phin," has made drip coffee popular around the globe. This article will walk you through the structure and use of the Vietnamese phin, teach you step by step how to make an authentic cup of Vietnamese drip coffee at home, and answer the question of which coffee beans to use for drip coffee grounds. It will also include bean recommendations from Front Street Coffee to help you choose the right beans for your phin, so your brew comes closer to the flavors of a Vietnamese street stall. [more…]

After coffee is roasted, aromatic compounds continue to escape outward. If the amount purchased exceeds what can be consumed within its peak-flavor window, the flavor will suffer greatly. This article begins with conventional storage ideas such as sealing, protection from light, coolness, and dryness, then focuses on analyzing the recently popular method of freezing coffee beans: it can indeed slow the loss of aroma, but improper handling can backfire. The article unfolds around three key details—sealing to prevent odor transfer, condensation and moisture damage, and avoiding repeated removal and return—and offers practical advice on portioning for storage. Front Street also reminds everyone that coffee is ultimately best enjoyed fresh, and buying only what you need is the worry-free approach. [more…]

For professional coffee knowledge exchange and more coffee bean information, please follow Coffee Workshop (WeChat official account cafe_style). For more specialty coffee beans, please add private WeChat Front Street Coffee (FrontStreet Coffee), WeChat ID: qjcoffeex. Coffee latte art is coffee [more…]

After a freshly brewed cup of coffee sits for a while, its aroma gradually dissipates, and its mouthfeel changes noticeably. Dark roasts become less smooth, medium-light roasts develop a more pronounced sourness and astringency, and a bitter, muddled finish may even appear. Why does cooling rob coffee of its appeal? If you reheat cold coffee or chill it with ice, can it regain its original flavor performance? This article analyzes the issue from two perspectives—chemical changes and sensory perception—and, through a comparative experiment between Front Street Coffee Kafa Forest and Front Street Coffee Yirgacheffe, explores practical remedies for cooled coffee. [more…]

Southern regions have recently been hit by continuous heavy rain, with severe waterlogging on roads in cities like Changsha and Wuhan, making travel difficult for residents and causing significant disruption to street-side shops. In such weather, a cup of coffee is a small comfort that keeps office workers energized and going, yet many customers who chose to pick up their orders at Luckin Coffee stores found that the paper takeaway bags were extremely flimsy in the rain, with the coffee spilling into the rain before they could even take a sip. Complaints and grievances about torn paper bags have been flooding social media, with consumers calling on the brand to improve its packaging, while store staff are equally miserable. This article examines the reasons behind this phenomenon and the voices from all sides. [more…]

Latte art is a direct reflection of a barista's comprehensive skills. Behind a seemingly light and airy pattern lies the layered coordination of espresso quality, milk foam condition, and pouring technique. From the practical perspective of Front Street Coffee, this article systematically explains the prerequisites and operational details of heart-shaped latte art: how to choose an espresso blend suitable for latte art, how to use a steam wand to create fine and smooth latte milk foam, and the specific application of the five pouring principles—integration, pouring point, convection, and finishing. Whether you are a beginner just starting with latte art or an experienced hand looking to correct your movements, you can find actionable references here to gradually pour a full and clean heart-shaped pattern. [more…]

Latte art is one of the most important skills for a barista. A beautiful cup of latte art may look effortless, but behind it lies repeated practice and accumulated experience. This article, from the practical perspective of Front Street Coffee, systematically explains the foundational points of espresso latte art: how to choose espresso beans suitable for latte art, how to steam fine and smooth milk foam, and five key details in the milk steaming process. It then further breaks down the five core principles of pouring latte art patterns, including the integration technique, high and low pouring, the trajectory of the pour point, the rhythm of the wobble, and the finishing technique, using a heart pattern as an example for an illustrated demonstration. Whether you are a complete beginner or an enthusiast hoping to improve your consistency, you can find actionable directions for practice here. [more…]

Nanyang coffee is a coffee beverage found in Malaysia, Singapore, Indonesia, and Thailand, and it is also the forefather of Chinese-style coffee. In the 19th century, after Hainanese immigrants moved to Nanyang, they combined Chinese cooking techniques to roast coffee beans, adding butter, sugar, salt, and other seasonings to reduce the bitterness of Robusta beans, creating a unique flavor that is rich and deeply roasted. To balance the extremely bitter taste, local Chinese developed a ordering system such as Kopi, Kopi C, and Kopi O, all derived from Hokkien pronunciation. This method of making coffee later spread back to Hainan, Hong Kong, and Macau, and evolved into variants such as white coffee and Oliang in different regions. Today, with specialty coffee in vogue, Nanyang coffee remains an important bond in the grassroots culture of Chinese communities in Southeast Asia. [more…]

Freshly steamed milk foam is dense and glossy, and the latte art takes shape smoothly, but in the blink of an eye, sunken "craters" appear on the surface, and the pattern blurs and distorts along with them. This rapid collapse of milk foam troubles many latte enthusiasts. To solve this problem, it is necessary to start with the principles of foaming and foam stabilization by milk proteins, then troubleshoot the details in the steaming process one by one, such as temperature, steam moisture content, and the force of tapping the pitcher, while also paying attention to the crema condition of the espresso and the pouring technique. This article systematically sorts out the various causes of milk foam dissipating and provides actionable improvement suggestions to help you make fine, delicate milk foam that lasts. [more…]

Recently, ChaPanda once again became the focus of public opinion due to food safety issues. On the evening of October 9, the brand's official Weibo posted two statements in succession, responding to the incidents of "using expired raw materials" and "a Ningbo customer complaining about finding a spider in a drink." Regarding the spider incident, ChaPanda said the source of the spider in the video was unknown and difficult to verify, and explained that the 600 yuan compensation was a response made by store employees to settle the matter, but this response did not calm netizens' doubts. A week earlier, ChaPanda had just apologized after a blogger's undercover investigation exposed the use of expired materials with replaced labels. In fact, since the beginning of this year, ChaPanda has been found multiple times in surprise inspections by market regulatory authorities in various places to have issues such as incomplete health certificates and expired raw materials. Although the brand emphasized that it had investigated and rectified stores nationwide, the frequent food safety hazards still make consumers worried. [more…]

The Coffee Flavor Wheel is an important tool in specialty coffee learning. From the first version published by the SCAA in 1995, to the updated version in 2016, to localized adaptations in Taiwan, Indonesia, and elsewhere, as well as simplified versions aimed at consumers, the flavor wheel has continually evolved. This article reviews the characteristics and limitations of each version, explores how to use the flavor wheel to taste and describe coffee more accurately, and examines how cultural differences influence flavor perception. [more…]

On the journey of learning about specialty coffee, I believe everyone is especially impressed by a colorful ring. It is the SCAA 2016 Coffee Flavor Wheel that has tormented you countless times. Of course, this is already a "simplified" version; the first edition of the flavor wheel in 1995 had two, one on the front. [more…]

Kopi Luwak, also known as civet coffee, is a name that even people who don't drink coffee often have heard of, yet within the specialty coffee community, this coffee is explicitly boycotted, and the root cause lies in its overly cruel production method. This time, Front Street Coffee takes a look at Indonesian Kopi Luwak: from the coconut palm civet stealing and eating coffee cherries, through biological fermentation in its stomach juices and intestines, to the traditional processing flow in which coffee farmers collect the feces, wash them, and sun-dry them; from the hybrid background of the Indonesian Golden Mandheling variety, to the similar practice behind Brazil's bird poop coffee; and then to the origin and method of Vietnamese egg coffee. At the same time, Front Street will also discuss the flavor controversy surrounding Kopi Luwak, its SCAA scoring performance, and specific suggestions for roasting and brewing, helping coffee lovers view this highly talked-about coffee more rationally. [more…]