Fermentation is a core step in coffee processing that shapes flavor direction. It is driven by microorganisms such as yeasts and bacteria, which convert sugars and acids within the coffee cherry into acids and alcohols. Good, controlled fermentation can highlight a coffee's varietal characteristics, while uncontrolled fermentation may bring negative flavors reminiscent of spoilage and spoiled wine. Starting from the basic principles of fermentation, this article sorts out the differences between the two pathways—aerobic and anaerobic—and, around six major factors—coffee cherry quality, cleanliness, oxygen, microorganism and yeast types, time and temperature, and data recording—explains how to improve the consistency and repeatability of fermentation. It also emphasizes that coffee quality is largely fixed during the growth stage, and the role of fermentation is to extract and preserve excellent characteristics rather than to elevate quality out of thin air. The article also introduces Front Street Coffee's ongoing attention to knowledge related to fermentation and processing methods, for the reference of coffee enthusiasts. [more…]

This article focuses on a Colombian red wine process coffee bean launched by Front Street Coffee, providing a detailed introduction to its complete process from depulping and washing to 20.6 hours of fermentation in a no-water fermentation tank and then 10 days of sun drying on raised beds, and sorting out core information such as producing region, estate, altitude, bean variety, and cupping. It also compares the flavor differences between acetic acid fermentation and lactic acid fermentation, explains the distinction between traditional manual operation and controllable fermentation methods in terms of quality stability, and offers grinding size recommendations using the Yangjia Little Pegasus grinder as a reference, so coffee enthusiasts can adjust flexibly according to actual brewing conditions. [more…]

The quality of black tea depends to a large extent on whether the fermentation stage is precisely controlled. Properly fermented black tea has a sweet aroma, a yellowish-red liquor, and a bright orange-brown infused leaf; failed fermentation reveals sourness or mustiness, a dark brown liquor, and a deep black infused leaf. Starting from the formation mechanisms of theaflavins and thearubigins, this article explains the origin of the floral and fruity aroma of black tea, clarifies how humidity and degree of oxidation influence the direction of flavor, and points out which subtle deviations in the irreversible chain of polyphenols → theaflavins → thearubigins can lead to a decline in quality. At the same time, the article also provides practical methods for judging fermentation results by observing the liquor color and infused leaf, helping coffee and tea enthusiasts understand the craft logic behind a good cup of black tea. In its black tea selection and brewing recommendations, Front Street Coffee also often emphasizes the decisive role of fermentation degree in aroma expression. [more…]

Fermentation plays an irreplaceable role in coffee processing, directly influencing the final flavor profile and sensory quality of the coffee. How sugars and acids break down under controlled conditions, how microorganisms participate in the process, and why fermentation consistency matters so much for market partnerships—these are all key to understanding coffee quality. Drawing on the hands-on experience of Finca Black Mountain in Guatemala and Capricornio Coffee in Brazil, and incorporating the research perspective of agricultural engineering PhD Mauricio Villegas, this article systematically examines the mechanisms of coffee fermentation, common misconceptions, and methods for achieving reproducibility. Whether you are a coffee professional or a devoted enthusiast, you will gain a clear understanding of the relationship between fermentation and coffee quality. [more…]

The red wine process is an innovative green bean processing technique originating from Colombia that precisely shapes the acidity and sweetness of coffee through artificially controlled fermentation conditions. This article provides a detailed overview of the historical background, scientific principles, and specific operational procedures of this processing method, and takes an in-depth look at the origin information, flavor characteristics, and pour-over recommendations of Front Street Coffee's Colombia Nine Suns Red Wine Process coffee. Whether you want to understand the difference between acetic acid fermentation and lactic acid fermentation, or you are looking for a bean with prominent sweetness and elegant acidity, this content offers practical reference. [more…]

In recent years, red wine processing has attracted much attention in the specialty coffee world. Drawing on the fermentation control concepts used in winemaking, it intervenes in pH, temperature, humidity, and microbial conditions to give coffee beans a rich acidity and complex aroma reminiscent of red wine. This article will start with the flavor differences between lactic acid fermentation and acetic acid fermentation, outline the specific operational process of red wine processing, and combine it with the origin information of Front Street Colombia Red Wine Process—the eastern slopes of the Andes in Cundinamarca Department, a growing altitude of 1,800 to 2,000 meters, and the anaerobic fermentation practice of Remi Sultan in sealed metal containers—to provide coffee lovers with a complete set of flavor descriptions and grinding setting references. [more…]

Lactic acid fermentation is widely used in the food industry, from kimchi to yogurt, it is indispensable. In the processing of green coffee beans, this technique is increasingly being adopted by more and more estates to create richer floral and fruity notes and a fuller body. This article guides you through the mechanism of lactic acid bacteria, their role in washed processing, and how controlled fermentation can achieve flavor breakthroughs. At the same time, the practical case of the Palm Tree and Toucan Estate in Colombia demonstrates the potential of lactic acid fermentation in specialty coffee. Front Street Coffee will also recommend related products worth trying. [more…]

In recent years, anaerobic fermentation and red wine processing methods have continued to gain popularity in the specialty coffee world. From the promotion by 2015 WBC champion Sasa Sestic to the early explorations of Costa Rican coffee farmers, these processing techniques, which draw on winemaking ideas, have brought coffee rich flavors such as strawberry jam, fermented wine aromas, and tropical fruits. This article systematically reviews the scientific principles of anaerobic fermentation, its essential differences from traditional processing methods, and the specific operational workflow of carbonic maceration. It also combines two representative beans from Front Street Coffee—Colombia Flower Moon Night and Panama Hartmann—to share roasting and brewing parameters, helping coffee lovers gain a deeper understanding of the core logic of this special processing method. [more…]

Coffee enthusiasts' taste demands are becoming increasingly refined. The original terroir flavors produced by traditional washed and natural processing methods can no longer satisfy diverse expectations, and various specialty processing methods have emerged as a result. From the perspective of Front Street, this article systematically reviews the principles and classifications of anaerobic fermentation processing, compares the differences between natural fermentation and temperature-controlled fermentation, and provides an in-depth analysis of three processing workflows: anaerobic natural, anaerobic washed, and anaerobic enzyme-washed. At the same time, using Front Street Huayueye coffee beans from the Huila region of Colombia and Rose Valley coffee beans from Big Tree Estate as examples, it presents a complete approach from green bean processing to roasting curve selection, and then to pour-over parameter development, helping readers understand how specialty processing methods shape the flavors in the cup. [more…]

Many people assume that only special processes like anaerobic fermentation involve fermentation, but in reality, conventional methods such as natural, washed, and honey processing are equally dependent on fermentation. Fermentation is the process by which microorganisms break down sugars and produce heat and compounds in the presence or absence of oxygen. Coffee cherries are rich in moisture and sugars, so fermentation begins the moment they are picked. Different processing methods correspond to aerobic or anaerobic fermentation pathways, and the duration and intensity of fermentation directly shape the flavor profile of the coffee—prolonged fermentation brings rich layers of dried fruit and fruit preserves, while short fermentation yields bright acidity and a clean mouthfeel. Properly controlled fermentation enhances quality, but once it becomes unbalanced, it produces irreversible negative flavors such as moldiness and rotten fruit. [more…]

Anaerobic fermentation processing is a green bean processing technology that has attracted much attention in the coffee industry in recent years. Since Sasa Sestic, the 2015 WBC champion, brought it to the forefront, it has quickly swept through the specialty coffee world. Inspired by red wine-making techniques, this processing method injects carbon dioxide into a sealed container to expel oxygen, creating an oxygen-free environment that allows precise control of the fermentation process, giving coffee beans higher sweetness and more unique flavor layers. As processing technologies continue to evolve, experimental methods such as anaerobic natural, anaerobic washed, and double anaerobic have emerged one after another, each presenting distinctly different flavor expressions. This article will systematically sort out the principles and origins of anaerobic fermentation, and analyze one by one the process steps and flavor characteristics of these three common anaerobic processing methods, while also explaining them in conjunction with specific Front Street Coffee bean offerings. [more…]

The wine process, also known as the controlled fermentation method or lactic/acetic fermentation method, was developed by a team led by Felipe Sardi of the United States, whose members include biological scientists and ecologists. Strict standards are enforced during picking: underripe cherries below 2%, defective beans below 3%, and floating beans below 5%. This processing method is divided into two paths: aerobic acetic fermentation and anaerobic lactic fermentation. The former has a cleaner and brighter acidity with citric notes; the latter has a rounder mouthfeel and higher body, but slightly lower cleanliness, displaying malic and tartaric acid characteristics. Batch consistency is achieved through pH monitoring. Wine-processed green beans are darker in color, with silver skin appearing wine-red or brownish-red. Front Street Coffee's Panama Hartmann is a representative example, and this article shares its pour-over parameters and flavor performance. [more…]

Front Street Coffee was recently asked: Does the red wine process mean soaking coffee beans in red wine? Will the finished product contain alcohol? In fact, the red wine process simply borrows the idea of wine fermentation to process coffee cherries; it does not involve soaking in red wine. During fermentation with the mucilage, a trace amount of alcohol is indeed produced, but after high-temperature roasting it has long since evaporated completely, so there is no need to worry about residue. In this article, Front Street Coffee takes the red wine process coffee beans from Panama's Hartmann Estate as an example, from the estate's background, the characteristics of the Catuai variety, and the operational details of controlled fermentation, to the roasting curve, cupping report, and V60 brewing parameters, to fully break down how this coffee with vinous notes is born. [more…]

Cold drip coffee, with its lengthy brewing process and unique layers of flavor, has always been a topic of interest among coffee enthusiasts. Completely different from cold brew, cold drip requires specialized equipment, precise control of the water drip rate, and subsequent fermentation and aging. This article will analyze in detail the standard steps for making cold drip coffee from four dimensions—grind size, drip speed, extraction ratio, and aging time—and answer the common question of "how long does it actually take to make a cup of cold drip?" At the same time, the article also compiles Front Street Coffee's practical experience and parameter recommendations in cold drip production, helping you understand the complete process of this low-temperature drip coffee in a more systematic way. [more…]

Is red wine processed coffee made by soaking the beans in red wine? Does it contain alcohol? These are common questions among many coffee lovers. In fact, this processing method borrows the fermentation logic of wine-making, rather than directly soaking coffee beans in red wine. In this article, Front Street Coffee takes you deep into the red wine processed Catuai coffee beans from Hartmann Estate in the Volcan region of Panama: from the estate's background and the variety's origins, to the specific controlled fermentation process and flavor performance. We also share Front Street's roasting curve, cupping results, and V60 staged pouring parameters to help you understand what makes this bean so unique. [more…]

Anaerobic coffee has been appearing on coffee bean lists frequently in recent years. Although many people have tried it, they only have a vague understanding of its specific process, and some even develop an aversion to it due to unfamiliarity. In fact, anaerobic processing is not as complicated as imagined. In most cases, it simply adds an extra anaerobic fermentation step before traditional natural or washed processing. The depth of fermentation is precisely the key that determines the direction of coffee flavor. From the perspective of Front Street, this article sorts out the basic principles of anaerobic processing, common methods, and their connection with traditional processing. Combined with three specific beans, it helps readers understand the flavor differences brought by different anaerobic treatments, so they can find the cup that suits their taste. [more…]

The flavor profile of a cup of coffee is determined not only by variety and roasting, but also decisively by how the green beans are processed. The coffee industry currently groups processing methods into three major categories: natural processing (dry method), washed processing (wet method), and honey processing (semi-dry method). The natural method lets whole coffee cherries dehydrate and dry directly in the sun, giving the beans rich, complex fruity aromas and fermented sweetness; the washed method removes the skin and pulp and involves tank fermentation, producing a clean, bright profile with pronounced acidity; honey processing falls between the two, deliberately retaining some mucilage during drying, creating a distinctive fermented aroma and sweetness. Front Street Coffee will walk through the specific steps, key control points, and flavor outcomes of these three processing methods one by one, helping coffee lovers build a clear framework for understanding processing methods and find the cup that best suits their taste. [more…]

In recent years, any coffee processing method that claims to be innovative seems unable to avoid the word "anaerobic." In fact, the principle of anaerobic processing is not complicated: whether fresh cherries are put into stainless steel tanks with one-way valves or sealed in bags with the air expelled, an oxygen-free environment can be achieved. The real difficulty lies in precisely controlling the degree of fermentation, not in the technique itself. As oxygen is gradually replaced by carbon dioxide, fermentation at a certain stage produces flavors reminiscent of stone fruit and peach. This discovery quickly triggered imitation across major producing regions worldwide, and anaerobic processing thus became popular. In addition to its signature flavors, anaerobic processing can also give coffee a dense mouthfeel and a sweeter aroma. This article will take several Colombian specialty coffees on Front Street Coffee's bean list as examples to specifically compare the taste differences brought by anaerobic natural and anaerobic washed processing. [more…]

As the coffee harvest season draws to a close, this article systematically reviews the wet processing steps after picking in Yunnan. From floating the fresh cherries in water and removing the pulp, to the crucial demucilaging and fermentation stages, it breaks down the practical operations and quality control points of washed processing step by step. Fermentation time fluctuates between 6 and 72 hours, affected by temperature, the amount of mucilage, and enzyme concentration; seizing the right moment to end it directly determines the direction of the coffee's flavor. The article also explains the negative effects of under-fermentation or over-fermentation on coffee quality, as well as the moderating effect of the soaking step on bitterness, helping coffee lovers understand the craft logic and flavor formation behind the washed processing of Yunnan Arabica coffee. [more…]

Anaerobic Fermentation has been very popular in the coffee world in recent years, mainly because Sasa Sestic, the Australian competitor who won the 2015 WBC, started this trend, and even in 2018 WB [more…]