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…]

A takeaway coffee every day is a daily habit for many office workers. But have you ever considered that the paper cup holding hot coffee might be quietly releasing trillions of plastic particles into your drink when it meets hot water? Researchers at the U.S. National Institute of Standards and Technology conducted experiments on this, and the results are concerning. In fact, multiple previous studies have confirmed that microplastics and nanoplastics have already invaded human blood and lungs. Facing this invisible health threat, bringing your own cup may be the simplest and most effective way to respond. [more…]

Many coffee shops do an internal tasting round before officially opening their doors to customers, commonly known as "morning calibration." The core purpose of this step is to confirm whether the coffee being served that day still tastes consistent, and if any abnormalities or negative changes in flavor are detected, adjustments must be made promptly. Some people wonder: if the equipment, water quality, parameters, and beans haven't changed, how could the taste change? In fact, espresso is particularly susceptible to the effects of coffee bean degassing and air humidity, so morning calibration is not superfluous. In addition to espresso, lattes and cold brew also need to be included in the testing. This article will explain one by one the reasons for morning calibration in coffee shops, what gets tested, and its significance at the food safety level. [more…]

Coffee itself belongs to the category of tropical fruits, but why can't fresh coffee cherries smell like the fruity aromas described on bean bags? The key to truly unlocking tropical fruit aromas in coffee lies in the aromatic compounds stored within the green beans and the chemical reactions that occur during roasting. Drawing on Front Street Coffee's cupping experience, this article will outline the logic behind the formation of tropical fruit flavors and their common types, and recommend several specialty coffees with intense ripe mango, distinct passion fruit sweetness and acidity, and pineapple notes. It will also explain why those lighter, harder-to-catch tropical fruit aromas appear less frequently. [more…]

When making cold brew coffee, many people habitually apply the grind-setting logic of pour-over—if they want to increase the extraction yield, they grind finer. However, through comparative experiments, Front Street Coffee found that after grinding cold brew coffee finer, the measured concentration was actually lower. The reason behind this is closely related to the extraction method of cold brew, which involves long periods of static steeping. This article will fully analyze this phenomenon and explain the key points to note when adjusting the grind for cold brew coffee. [more…]

Many people are used to drinking pour-over coffee while it's hot, but what exactly does temperature do to the flavor of pour-over? Starting from coffee refractometer measurements, this article explores how pour-over coffee tastes at different temperatures and explains why hot coffee better reveals the full flavor of the coffee. We'll also introduce recommended products from Front Street Coffee to help you nail the ideal drinking temperature in your daily brewing. [more…]

Although Peruvian coffee is not as renowned as that of Colombia or Brazil, it has risen rapidly in the international specialty market thanks to its complex flavors, mild and balanced taste, and extremely high cleanliness. As the world's number one producer of organic coffee, Peru's coffee industry has gone through a tortuous journey from colonial introduction and the large-estate model to the revival of cooperatives. In this article, Front Street will take you deep into Peru's coffee-growing regions, grading system, and processing methods, with a special focus on the northern specialty region of Cajamarca, analyzing its white floral, prune, citrus, and black tea-like flavor profile through a cupping experience of a washed Geisha. [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…]

The coffee flavor wheel is a recognized tasting tool in the specialty coffee community, but when faced with descriptors like citrus, berries, nuts, and chocolate, many people don't know how to match them. Starting from the high-resolution image of the latest SCAA flavor wheel, this article systematically sorts out the compositional logic of coffee flavor: the relationship between the four basic tastes of sour, sweet, bitter, and salty and the roast level, the proportion data of each taste substance, the subdivision of the acidity spectrum, bitterness spectrum, sweetness spectrum, and saltiness spectrum, as well as an item-by-item analysis of the nine major flavor groups including floral and fruity, green and herbal, nutty and cocoa, sweet, spicy, sour and fermented, alcoholic fermented, roasted, and other. The article also intersperses Front Street Coffee's daily training methods and representative bean recommendations, helping readers build a complete tasting framework from smelling to drinking. [more…]

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…]

Many coffee enthusiasts have wondered: when Americano tastes sour, does it mean the beans are spoiled or have been sitting too long? In fact, for black coffees like Americano, pour-over, and cold brew, perceiving acidity is often perfectly normal. Starting from the daily offerings at Front Street Coffee, this article sorts out the major sources of acidity in Americano—including the choice of roast level, the fruity acidity inherent in the coffee beans themselves, possible channeling and grind inconsistencies during extraction, and the pattern of increased perceived acidity as the coffee cools—to help you determine whether a sour Americano is a flavor characteristic or a quality problem. [more…]

In coffee brewing, the choice of measuring tools may seem like a minor matter, yet it directly affects consistency in the cup. A measuring spoon is convenient, but it measures volume rather than weight; due to differences in variety, cultivation, and roasting, the same level spoonful of different coffee beans may scoop out 9g or 11g, an error large enough to change the direction of the flavor. Front Street Coffee once conducted an experiment with Geisha Village Red Label Geisha: with water volume and other parameters unchanged, adjusting the dose by just 1g produced noticeable differences in concentration and extraction yield. This article will use experimental data to explain why electronic scales have become the first choice of coffee shops, and to show why measurement accuracy must be even higher under pressurized espresso extraction. [more…]

Friends who brew coffee with a moka pot almost always struggle with one question: how do you pick a bean that isn't sour? After all, coffee made in a moka pot is highly concentrated, so any sourness becomes very obvious once it appears. The good news is that as long as you stick to the directions of "full-bodied, low-acid, rich in oils," there are excellent choices from beginner to advanced levels. [more…]

The taste of coffee does not have only three dimensions—sourness, sweetness, and bitterness. Saltiness also objectively exists in the coffee liquid, but it is usually masked by other flavors. When an obvious salty taste appears in a pour-over, espresso, or cold brew coffee, it often means that there is a problem in one of the links: bean quality, water quality, or brewing parameters. Starting from the daily communication cases of Front Street Coffee, this article sorts out the sources of saltiness in coffee, analyzes the two typical situations of under-extraction and excessively high concentration, and gives judgment methods and directions for parameter adjustment. At the same time, in response to the problem that cold brew coffee tastes too weak, the article also provides bean selection suggestions to help coffee lovers make a cup of cold brew with clear flavor and balanced acidity and sweetness in summer. [more…]

When ordering at a café, you'll often see a glass of ice water served alongside an espresso, and many enthusiasts are in the habit of drinking ice water before their coffee. Can this glass of ice water actually help us perceive coffee flavors more clearly? Front Street Coffee will approach this from the perspective of oral sensory cleansing, explaining how ice water enhances the tasting experience by rinsing away residue, stimulating saliva production, and numbing the palate through low temperature, while also tracing the origins of this practice in espresso culture. It will also discuss whether pour-over coffee is suited to the same approach, and why room-temperature water is gentler on the stomach and intestines. [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…]

Aftertaste is an indispensable part of coffee tasting. It refers to the comprehensive sensory experience brought by the substances remaining in the mouth and throat after swallowing coffee. Compared with taste and aroma, aftertaste is more subtle and requires certain techniques to be fully perceived. From the perspective of Front Street, this article explains the mechanism behind aftertaste, shares practical methods for perceiving it such as closed-mouth exhalation, and analyzes the difference between good aftertaste and bad aftertaste. At the same time, combined with specific products in the Front Street bean list, it explains the aftertaste emphases of coffees with different roast levels, and discusses the differences in aftertaste length between pour-over and espresso as well as their causes. [more…]

On a scorching summer day, when you crave iced coffee but don't want to give up the full flavor, many enthusiasts consider brewing hot coffee first and then adding ice to cool it down. While this method is feasible, it tends to make the coffee taste weak. This article uses a real test case of Front Street Coffee's Finca Diviso·Geisha to illustrate how the concentration drops from 1.49% to 1.09% before and after adding ice to a hot pour-over, as well as the noticeable decline in taste and flavor. At the same time, the article also offers adjustment ideas for iced pour-over: change the grind size from a 20-mesh sieve passing rate of 75%~80% to 80%~85%, change the coffee-to-water-to-ice ratio to 1:10:6, and keep 15g of coffee, 92°C water temperature, a three-stage pour, and a 2-minute extraction. This way, you can achieve a refreshing taste while retaining flavors such as grape, passion fruit, and apricot, presenting a full-bodied juicy mouthfeel. [more…]

Guatemala, as an important specialty coffee-producing country in Central America, is home to many distinct regions with their own styles, among which New Oriente is an emerging region that has attracted much attention in recent years. This article will provide an in-depth analysis of the altitude, climate, and harvest period characteristics of the New Oriente region, and describe in detail the flavor expression of its coffee, including a balanced mouthfeel, full body, and richly layered notes of passion fruit, strawberry sandwich cookies, blueberry, and chocolate. At the same time, the article will also explore how Guatemala's volcanic soil and high-altitude environment together shape the intense flavor of its hard beans, and include an introduction to the country's main coffee-producing regions and well-known bean varieties, offering coffee lovers a complete regional guide. [more…]

Most of the sugars in coffee beans have already been transformed and degraded during roasting, and the remaining sweet-tasting molecules are easily masked by flavors such as acidity and bitterness. In this article, Front Street will break down the underlying principles of high-sweetness extraction and explain in detail the four-character brewing formula of "fine, high, large, fast"—grinding finer, raising the water temperature, increasing the flow rate, and speeding up extraction—using medium-light roasted beans as the experimental subject, demonstrating step by step the specific parameters and techniques for each stage; for medium-dark roasted beans, which are loose in texture and cannot withstand aggressive extraction, the "high concentration, low extraction" approach is recommended, paired with a Kono dripper and a simple one-pour technique, which can likewise brew a cup of coffee with full sweetness and restrained bitterness. At the end, the article also introduces diverse extraction methods such as variable-temperature brewing, for enthusiasts to try freely. [more…]