When brewing coffee, most people focus on whether the water's TDS is in the appropriate range, but few pay attention to whether repeatedly boiling the hot water affects the coffee's flavor. Some believe that coffee brewed with water that has been boiled multiple times will decline in quality. To verify this claim, Front Street Coffee designed a controlled experiment, using a TDS test pen and a coffee concentration meter, brewing a medium-light roasted Sidamo Hachira 8.0 by immersion in a clever cup, using water boiled for the first through fourth times respectively, and recording the TDS value of the water and the coffee concentration performance each time. This article will present the experimental setup, operating procedure, and data results one by one, to help coffee enthusiasts determine whether repeatedly boiled water is truly unsuitable for brewing coffee. [more…]

When brewing pour-over coffee, water quality is one of the key variables that determines flavor expression. This article focuses on the two core indicators of water: hardness and pH, explaining the TDS range recommended by the SCAA as well as the water quality range that more easily yields good taste in actual brewing, and explaining the effects of calcium and magnesium ions on coffee acidity, sweetness, and aroma. The article will also analyze one by one whether tap water, filtered water, purified water, and mineral water are suitable for brewing coffee, reminding readers to pay attention to the TDS and mineral content on labels, and to avoid judging water quality based on price alone. Finally, it offers practical advice on water for daily brewing to help coffee enthusiasts reproduce coffee flavors more consistently. [more…]

Front Street Coffee received a question from an enthusiast who wants to know how to get started with coffee concentration measuring instruments like ATAGO. This article will demonstrate the operating procedure of the instrument step by step, explain the meaning of the two readings, Brix and TDS, and show how to use the measured TDS value to calculate the coffee's extraction yield. The article will also introduce the two core standards of the Golden Cup theory—extraction yield of 18%–22% and concentration of 1.2%–1.45%—as well as the flavor characteristics brought by under-extraction and over-extraction, helping you more accurately judge whether a cup of coffee falls within the ideal range in your daily brewing. [more…]

Many coffee enthusiasts, after purchasing equipment and beans, often overlook the critical impact of water quality on flavor. Tap water, filtered water, or purified water—different TDS levels will directly change the extraction results. From the perspective of Front Street, this article explains how calcium and magnesium ions influence the taste, why tap water tends to produce astringency, and why purified water leads to a hollow sensation. It also cites the SCAA standard of 75-250ppm along with practical recommendations, advocating the use of filtered or bottled water, and specifically mentions Nongfu Spring as a reference choice for daily brewing. [more…]

Coffee extraction is the key step that determines flavor. About 30% of coffee beans consists of soluble substances, including both aromatic components and mouthfeel-related compounds, and a higher extraction yield does not necessarily mean better quality. This article systematically introduces concentration measurement methods (refractometer, conductivity pen, evaporation and drying), explains the extraction yield conversion formula in detail, and provides specific calculation steps for different brewing devices such as immersion, pour-over, and espresso. It also includes the golden cup concentration recommendations from the SCAA and SCAE, as well as relevant product information from the Front Street Coffee brand, to help enthusiasts understand extraction more scientifically. [more…]

Water is the largest component of black coffee and directly participates in and influences the extraction process, so differences in water quality often bring about completely different flavor expressions. There are many types of bottled water on the market, with prices ranging widely from high to low, and whether more expensive water is more suitable for brewing coffee has become a question for many brewing enthusiasts. This article uses two types of bottled water with明显 price differences as test subjects, and adds Nongfu Spring, commonly used in stores, as a control, conducting blind tasting comparisons with two coffees, Yirgacheffe Red Cherry and Diamond Mountain. At the same time, from the perspectives of acidity and alkalinity, softness and hardness, TDS, and calcium and magnesium ions, it explains the principles by which water quality affects extraction, helping coffee enthusiasts understand how to choose more suitable water for brewing coffee. [more…]

In a cup of black coffee, water makes up the vast majority, so its impact on flavor must not be underestimated. Different brands of drinking water vary in mineral composition, hardness, and pH, so the coffee brewed with them naturally takes on different characteristics. To investigate this variable, Front Street Coffee selected four common drinking waters—Baisui Mountain, Nongfu Spring, Ganten, and C'estbon—and used the same Costa Rica Mozart coffee beans to make cold brew, measuring TDS, coffee liquid concentration, and recording flavor performance one by one. The experiment found that the amount of calcium and magnesium ions in water affects extraction efficiency and taste direction, while Nongfu Spring with medium TDS and C'estbon purified water each showed distinct stylistic differences. This article will present the full experimental process and tasting results, and offer water selection suggestions for different taste preferences. [more…]

When brewing a pour-over coffee, water accounts for up to 98.7%, making its importance no less than that of the coffee beans and grinder. In this article, Front Street Coffee analyzes how water quality affects flavor, the mechanism by which calcium and magnesium ions in water act, and the recommended TDS range. It also uses examples to explain how, when coffee develops off-flavors or negative mouthfeel, you can troubleshoot the problem by switching water sources such as Nongfu Spring, helping enthusiasts on a limited budget spend their money where it matters most. [more…]

As the primary raw material, water not only makes up the vast majority of a cup of black coffee, but also influences the extraction of different substances, thereby producing distinct flavors and mouthfeel. Therefore, all of us should understand the importance of water to coffee. Common drinking water on the market varies from brand to brand, in the ingredients it contains, and in its purification processes. [more…]

To brew a delicious cup of coffee, you need not only good beans but also good water. In brewed coffee, water accounts for over 98% of the final cup. Therefore, choosing the right water for brewing is also crucial. So what kind of water is actually suitable for brewing coffee? First, Front Street Coffee will explain the requirements for water suitable for brewing coffee. One [more…]

Coffee extraction, simply put, is the process of using water to dissolve the flavorful essence from coffee beans. It seems like something that can be summed up in a single sentence, but behind it lies a whole series of precise variables: extraction yield, total dissolved solids, water quality, grind size, temperature, time, and more. Roasted coffee beans are about 30% soluble, and what we aim for is extracting 18-22% of that—the optimal range. We don't want under-extraction, which leads to sharp acidity and a thin, bland cup, nor over-extraction, which brings bitterness and off-flavors. This article will start from the basic definition of extraction and break down, one by one, the nine core factors that affect extraction, helping you build a systematic framework for understanding brewing so that every cup consistently delivers the ideal flavor. [more…]

Regarding what water to use for brewing coffee, there has long been a popular saying: "Don't use purified water." Does this claim actually hold up? Water quality really does influence how coffee flavors express themselves, and purified water is called into question mainly for two reasons: first, its extraction efficiency is on the low side, because the water lacks calcium and magnesium ions to help dissolve flavor compounds; second, purified water has poor conductivity, which can cause the boiler probe in a coffee machine to malfunction, leading to abnormal refilling or even breakdowns. Through comparative experiments, Front Street found that coffee brewed with purified water versus mineral water shows only slight differences in concentration and extraction yield—hard for an ordinary person to notice. What is truly unsuitable for brewing coffee is hard water with a TDS above 175 ppm. This article will analyze these points one by one and offer water-quality recommendations for everyday brewing. [more…]

Coffee is a futures commodity with trading volume second only to crude oil worldwide, yet brewing it at home often makes it hard to replicate cafe flavors—the key lies in whether one understands the SCA Golden Cup extraction standards. This article starts from the principles of soluble substances and solid-liquid extraction, explaining the Golden Cup range of TDS concentration 1.15% to 1.35% and extraction yield 18% to 22%, and systematically sorts out the effects of time, grind size, water temperature, and coffee-to-water ratio on flavor. The article also combines Front Street Coffee's brewing comparison using Huakui 5.0 as an example and store parameters to help readers translate abstract standards into operable daily pour-over brewing. [more…]

In the Golden Cup extraction theory, extraction yield and concentration are the two core metrics for assessing the flavor state of coffee. However, coffee that falls within the ideal range is not necessarily delicious, and coffee outside the range is not necessarily undrinkable—the key lies in how to use these two values to help adjust the brewing plan. From the perspective of Front Street, this article first clarifies the basic definitions and ideal ranges of extraction yield and concentration, then explains in detail how to use two sets of concentration measuring tools, and finally uses the Santa Vini anaerobic natural beans as an example to fully demonstrate the entire process from weighing the liquid weight to plugging it into the formula to calculate the extraction yield. [more…]

Espresso is the foundation of various Italian-style beverages such as Americano, latte, and cappuccino. It is extracted by forcing approximately 92°C hot water under high pressure through a finely ground and compacted layer of coffee powder using an espresso machine. This article focuses on the extraction standards for espresso, covering the coffee-to-water ratio, extraction time, TDS measurement, and the calculation method for extraction percentage, and outlines the complete operational steps from wiping the portafilter basket to cleaning the group head. It also introduces the recipe concepts and flavor characteristics of Front Street Coffee's four espresso blend beans, as well as the espresso extraction protocol used in Front Street Coffee shops, providing a systematic reference for coffee enthusiasts. [more…]

When making cold brew coffee, should the grind size be coarse or fine? Many enthusiasts habitually assume that grinding finer will increase the concentration, but in a low-temperature, still-steeping extraction environment, this logic does not necessarily hold. Through practical experiments, Front Street used the same Yirgacheffe beans, the same coffee-to-water ratio, and the same steeping time to make cold brew with fine and coarse grinds respectively, testing the concentration and tasting the flavor differences. The results showed that the coarse grind actually had a slightly higher TDS, and its flavor performance was also brighter and sweeter. This article will explain this phenomenon from the perspectives of water temperature and particle movement, and provide grinding recommendations and applicable conditions for making cold brew coffee, helping you make a cup of cold brew with excellent concentration and flavor. [more…]

The world of espresso is built on the foundation of espresso, from which Americano, latte, cappuccino, flat white, and mocha are all derived. Espresso is made by forcing hot water at about 92 degrees through a finely ground and compacted layer of coffee under high pressure, extracting a liquid rich in flavor and relatively high in caffeine per unit. Americano originated during World War II, when American officers diluted espresso with water to mimic the taste of drip coffee, a practice that also carried a hint of European mockery. Front Street Coffee uses a hot Americano water-to-liquid ratio of about 1:4.5, and an iced Americano ratio close to 1:9, and offers four espresso blend beans to meet different needs. This article will also explain in detail the extraction standards, the effects of grinding and time on flavor, TDS measurement, as well as the seven-step espresso-making process and in-store extraction solutions, helping enthusiasts understand the logic behind a cup of espresso. [more…]

Espresso is the foundation of the Italian beverage system, and Americano, latte, cappuccino, flat white, and mocha are all derived from it. This article centers on the extraction principles of espresso, sorts out its historical origins and flavor differences with Americano, and introduces in detail the positioning and characteristics of four espresso blend beans from FrontStreet Coffee. At the same time, the article also compiles reference standards for Italian-style extraction such as dose, liquid weight, and time, explains TDS measurement and the calculation method for extraction yield, and finally includes the seven-step espresso-making process and extraction scheme used in FrontStreet stores, for coffee enthusiasts to systematically understand the making and tasting of espresso. [more…]

Many coffee enthusiasts have encountered this confusion: for the same beans, why does the taste always differ between what you brew yourself and what a Front Street barista brews? In fact, this involves two core concepts—extraction yield and concentration. This article, based on the daily experience of Front Street Coffee (FrontStreet Coffee), systematically explains what coffee extraction yield is, how to measure extraction yield using a TDS concentration meter, and the conversion relationships in the SCAA Golden Cup standard among 18%–22% extraction yield, 1.15%–1.35% concentration, and a 1:12–1:15 coffee-to-water ratio. The article also reviews the historical origins of the Golden Cup theory and, using Front Street's brewing of Panama Elida Natural Typica as an example, provides complete staged pouring parameters and the extraction yield calculation process, helping you brew a cup of pour-over coffee at home that is not over-extracted and has a pleasing flavor. [more…]

Cold brew coffee is extracted in a low-temperature, still environment, and many people habitually assume that grinding the coffee finer will increase its strength—but is that actually true? Through comparative experiments, Front Street Coffee found that a coarser grind actually yields a higher TDS reading in cold brew. Starting from the underlying logic of water temperature and particle movement, this article will explain why the "finer grind equals stronger coffee" theory that applies to high-temperature pour-over does not hold for cold brew. It also offers coffee bean recommendations suitable for cold brew, suggested coffee-to-water ratios, and points to note on grind selection for beans of different roast levels, helping you make a specialty cold brew with just the right strength and an aroma that isn't masked by added ingredients. [more…]