The Agtron is a professional optical instrument used in the United States to determine coffee roast level. It analyzes the caramelization state of sugars inside coffee beans through infrared wavelength analysis, indicating roast depth with values from 100 to 25. This article provides a detailed introduction to the working principles of the Agtron M-Basic colorimeter, lists a complete correspondence table of numerical and color group values from extremely light roast to extremely dark roast, and explains that the flavor-recognizable range as determined by the SCAA Technical Standards Committee is actually 30 to 90. For coffee enthusiasts who wish to precisely control their roasting curves, understanding the relationship between Agtron values and roast level is an important foundation for grasping flavor direction. Front Street Coffee also often refers to this indicator in roasting practice to help present the best flavor expression of different beans. [more…]

In coffee roasting, how can we ensure that every batch of beans achieves consistent quality? In addition to relying on cupping to evaluate flavor, we also use the RoAmi roast degree analyzer to record the Agtron caramelization value of the coffee beans, and retain historical data for reference. The RoAmi is essentially a colorimeter, with SCAA's Agtron algorithm embedded inside, capable of calculating the roast value by reading the color data of the bean surface or ground surface. This article will introduce how to use this instrument, the meaning of the Agtron value, and how to calculate the Roast Delta value from the bean color value and ground color value, and interpret the guiding significance of this value for roasting rhythm and flavor performance. [more…]

Many friends who want to learn about coffee bean roasting are curious about one question: how to determine the roasting degree of coffee beans. Should a coffee bean be dark roasted or light roasted, and then how light should light be, and how dark should dark be? On what basis does Front Street Coffee determine the roasting of all these coffee beans it sells? [more…]

Judging the roast level of coffee beans by the naked eye alone, based on how light or dark the color appears, is clearly not rigorous enough. In the industry, a colorimeter is more commonly used to measure the degree of caramelization. This article will start with the measurement principle, explain the meaning of the Agtron value (color value), the difference between whole-bean color and ground-coffee color value, and how the RD value calculated from the difference between the two reflects roast uniformity. It will also explain how factors such as processing method affect the measurement results. Front Street Coffee will also present the commonly shared Agtron value roasting chart to help coffee enthusiasts more systematically understand the scientific basis behind roast assessment. [more…]

During the bloom phase of pour-over coffee, whether the coffee bed puffs up into a large dome or stays relatively flat actually hides quite a bit of information. Although the degree of doming can't directly tell us whether the coffee tastes good, it can reflect the freshness of the coffee beans, the roast level, and the extraction efficiency during brewing. This time, Front Street Coffee will help everyone understand: why do some beans puff up like a balloon during the bloom while others stay flat and collapsed? What role does carbon dioxide play in this? Why do dark roasts and fresh beans puff up more? How do extraction parameters influence the degree of doming? Once you understand these things, you can read the bloom dome as a "bean status file" rather than mistakenly treating it as a standard for judging flavor quality. [more…]

Want to roast coffee beans at home but don't know where to start? Front Street Coffee, drawing on the practical experience of baristas, introduces the key operating points of drum roasting and compiles SCAA's eight-level roast degree comparison chart—from light roast with an Agtron color value of 95 to Italian roast with a color value of 25, explaining one by one the timing of each stage's release from the roaster, appearance changes, and flavor performance. The article also compares the time differences between a professional roaster and drum roasting for the same Brazilian Cerrado Red Bourbon coffee beans, helping coffee enthusiasts understand how roast degree determines the acidity-bitterness direction of a cup of coffee. [more…]

Many coffee enthusiasts rely on the rule of thumb that acidity means light roast and bitterness means dark roast to judge the degree of roasting, but the industry has a more precise standard—the Agtron color value. From the perspective of Front Street Coffee, this article systematically sorts out a total of eight levels from light roast to Italian roast, and, combined with the timing of first crack and second crack for dropping the beans, explains the flavor direction and the changes in acidity and bitterness at each stage, and also explains the meaning of terms such as City Roast. At the same time, Front Street also shares how to use flavor descriptions to help consumers judge the roast level more intuitively, and gives brewing parameter suggestions corresponding to medium-light roast and medium-dark roast, so that you no longer feel troubled by technical terms. [more…]

The roast level of coffee beans directly influences the flavor expression in the cup. From the extremely light roast with an Agtron color value of 95 to the Italian roast with a color value of 25, each stage has its corresponding drop time and flavor characteristics. This article systematically sorts out the flavor variation patterns of 8 roast levels, and combines the actual classification methods of commercially available coffee beans to help readers understand the taste directions of light roast, medium-light roast, medium roast, medium-dark roast, and dark roast. The article also uses Front Street Coffee representative beans such as Yirgacheffe, Mozart, Queen's Farm Brazil, and Golden Mandheling as examples to illustrate how different roast levels shape the balance of acidity, sweetness, and body. [more…]

From seed to cup, roasting is the key step that unlocks flavor. The degree of roast affects not only the balance of acidity and bitterness but also whether the mouthfeel is light or rich. This article begins with the roasting stages, introduces how the SCA Agtron scale quantifies roast level, and explains why a light roast preserves the origin's true character while a dark roast delivers intensity and depth. It then uses Ethiopia Yirgacheffe and Indonesia Golden Mandheling as examples to show how Front Street Coffee chooses roast levels based on each bean's characteristics, ultimately producing completely different tastes in the cup. Whether you prefer fruity acidity or rich depth, understanding roast level will help you find the flavor you love more precisely. [more…]

What degree of coffee roasting is considered appropriate? Starting from the key milestone of first crack, this article systematically sorts out the logic for determining coffee bean roast level, and with the help of Agtron color values, divides roast degree into eight levels: light, cinnamon, medium, deep, city, full city, French, and Italian, explaining one by one the timing for dropping each level and its flavor direction. At the same time, it answers the correspondence between the Roasting percentage markings commonly used by roasters and Agtron color values, helping coffee enthusiasts quickly understand the roasting information on packaging. The article also includes Front Street Coffee's specialty bean recommendation channel for further communication and purchasing. [more…]

Many people are used to judging a bean's roast level or the brew's strength by observing the color of the coffee liquid, and even using it to decide whether a coffee tastes good. But the factors affecting coffee's liquor color go far beyond one—the degree of roast, the level of concentration, and differences in filtration equipment can all make the same bean display completely different hues. Starting from Front Street's own side-by-side testing, this article breaks down one by one how roast level, concentration, and filtration method act on coffee color, and explains why a wine-red liquor color does not equal good taste, and why liquor color can only serve as a reference indicator for a particular bean rather than a standard of judgment. [more…]

When brewing pour-over coffee, a layer of foam often floats on the surface of the liquid in the dripper, sometimes rich and golden, sometimes thin and whitish. What exactly makes up this layer of foam? What can its color depth and quantity tell us about the brewing? From the perspective of Front Street, this article analyzes the sources of the foam's components, explains how large coffee particles affect the foam's color, and further reveals how the degree of roasting and the freshness of the coffee beans determine the richness of the foam, helping you adjust your pouring technique and judge the characteristics of the beans by observing the state of the foam. [more…]

What exactly determines the flavor of coffee beans? Origin, variety, and processing method lay the foundation, but roasting is the key step that unlocks their potential. From the perspective of Front Street Coffee, this article systematically sorts through the three major roasting levels—light, medium, and dark—and the eight stages within them, explaining how the Maillard reaction and caramelization reaction affect coffee's acidity, sweetness, bitterness, and body. At the same time, drawing on specific beans such as Yirgacheffe Gedingding, Natural Red Cherry, PWN Golden Mandheling, and Lintong Mandheling, it offers pour-over parameter recommendations for medium-light and medium-dark roasts, helping coffee lovers choose the right roast level according to their personal taste. [more…]

Cupping is a core method used in the coffee industry to objectively evaluate coffee flavor and quality, and it is also an important part of barista training. This article systematically reviews the significance and operational logic of cupping, and compares in detail three approaches: the Brazilian cupping method, the SCAA standard cupping method, and the pour-over cupping method recommended by Front Street Coffee. The article points out that Brazilian cupping focuses on identifying defects and is a negative evaluation; SCAA cupping emphasizes positive assessment of aroma and flavor; while the cupping method used by Front Street Coffee simulates daily brewing equipment and is closer to actual cafe output. The three methods each have different emphases in roast level, extraction method, and evaluation items, and understanding these differences helps roasters and coffee professionals judge coffee quality more accurately. [more…]

To enjoy a cup of pour-over coffee with a fresh flavor and clean mouthfeel, there are actually discernible guidelines when choosing beans. The degree of roast, the processing method, and the terroir of the growing region are the three key factors that determine the direction of a coffee's flavor. A light roast preserves more organic acids and delicate aromas, while the washed process makes the fermentation level of the coffee beans more controllable, and the regions of Africa and Central and South America are especially concentrated sources of fresh-flavored beans. Based on Front Street's bean-selection experience, this article lays out a practical approach to choosing coffee beans with high cleanliness and a fresh flavor, and recommends specific qualifying beans such as Front Street Yirgacheffe·Gedeb and Front Street Wander Estate·Washed Geisha, suitable for both pour-over and cold brew preparation. [more…]

Raw coffee beans can only release those thousand-plus aromatic compounds and become a fine brew in the cup after roasting. During heating, substances such as sugars and lipids undergo Maillard reactions and caramelization, while the coffee bean fibers gradually carbonize, ultimately approaching a charcoal-like state. Based on the degree of carbonization and surface color, the industry classifies roast levels into three major categories: light, medium, and dark. Under different roast levels, the amount of precursor aromatic substances retained in coffee beans and the degree of fiber caramelization differ, resulting in distinctly different acid-bitterness balance and regional flavors. Light roasts are bright with acidity and aroma, medium roasts are balanced with nutty and creamy notes, and dark roasts are full-bodied with interwoven bitterness and sweetness. Starting from the principles of chemical reactions, this article will break down the flavor characteristics of the three roast levels one by one, recommend representative Front Street specialty coffee beans for each roast level, and also discuss which roast level is more in line with health considerations, providing a reference for coffee lovers' daily purchasing decisions. [more…]

The flavor of coffee, 60% comes from the raw beans, 30% comes from roasting, and 10% comes from brewing. It can be seen that there are many factors affecting the flavor of coffee. Then, as roasters, how to determine the degree of roasting of coffee b [more…]

On professional coffee review websites like coffeereview.com, you will often see a pair of Agtron values listed below the attribute scores. What exactly do these numbers mean? And how do they relate to coffee roast color differences? This article will take you through an in-depth look at the meaning of Agtron values, the principles of measurement, and their applications in the coffee industry. From the differences in readings between whole beans and ground coffee, to the impact of roast level on flavor, and how consumers can use this data to choose their preferred coffee, we break it all down one by one. At the same time, the article will also mention practical uses by brands such as Front Street Coffee in product descriptions, helping you interpret coffee roast information more professionally. [more…]

Many coffee enthusiasts, beyond their daily consumption, have begun trying their hand at roasting coffee beans. However, home roasting often runs into the problem of uneven bean color, and the degree and consistency of roasting are exactly what determine the final flavor in the cup. This article draws on the practical experience of Front Street Coffee, first introducing the feasible tools and operational key points for home roasting, then systematically sorting through the eight roast levels defined by the SCAA—from light roast to Italian roast—explaining one by one the Agtron color values, the timing of removal from the roaster, and the corresponding flavor performance, to help readers build an understanding of the correspondence between roast level and taste, and to gain a deeper understanding of the craft logic behind every cup of coffee. [more…]

Many people start their espresso journey with dark roast beans—rich caramel and dark chocolate, with a prominent, straightforward bitterness that, once combined with milk, becomes almost a liquid dessert. The barrier to entry is low, and it fits the general public's initial idea of coffee. But the world of coffee flavor is far broader than this stretch. As the number of shots pulled increases, many people naturally begin to [more…]