Brewing coffee is as much of an art as it is a science. The history of coffee brewing equipment is rich, and methods of brewing are culturally dependent. Of the thousands of coffee machines and coffee brewing devices invented since the advent of coffee consumption, only a few have gained worldwide popularity.
The coffee brewing methods discussed below are recommended since they have been found to maximize the extraction of the beneficial flavors of coffee, while minimizing the extraction of bitter coffee compounds a nd undesirable components.
Coffee roasting is a chemical process by which aromatics, acids, and other flavor components are either created, balanced, or altered in a way that should augment the flavor, acidity, aftertaste and body of the coffee as desired by the roaster.
Body is the weight of the coffee that can best be sensed by allowing the coffee to rest on the tongue and by rubbing the tongue against the roof of the mouth.
Coffee body ranges from thin, to light, to heavy and is a result of the fat content. The viscosity, however, results from proteins and fibers in the brew. Medium and dark coffee roast styles will have a heavier body than lighter roasted coffees, but conversely will have less acidity.Read more
The perceived acidity of coffee results from the proton donation of acids to receptors on the human tongue. Coffee acidity is typically a highly valued quality especially in Central American and some East African coffee. Sourness, however, is an extreme of acidity and can be considered a coffee defect.
Acidity has been correlated with coffees grown at very high altitudes and in mineral rich volcanic soils. The perceived acidity of washed coffees is also significantly higher than the acidity found in naturally (dry) processed coffee. This is likely due to an increase in the body of naturally processed coffees relative to wet processed coffees since body masks the acidity in coffee. The coffee acid content in a brew is also greatly dependent upon the coffee roasting degree, type of roaster, and coffee brewing method.
The pH of a coffee has been found to correlate with the perceived acidity in coffee by Pangborn, Sivetz and Desrosier, and Griffin and Blauch; whereas Voilley et al. suggests that titratable acidity produces a better correlation to perceived coffee acidity.Read more
Decaffeinating coffee is achieved through a variety of decaffeination processes, all of which are relatively harmless to your health, but harmful to coffee quality. Almost every process for decaffeination consists of soaking the beans in water to dissolve the caffeine, extracting the caffeine with either a solvent or activated carbon, and then re-soaking the coffee beans in the decaffeinated water to reabsorb the flavor compounds that were lost in the initial extraction.
The solvents typically used are methylene chloride or ethyl acetate, which both have a low boiling point. Since ethyl acetate is found naturally in fruits you will hear people call this process "natural." In any case the solvent never comes in contact with the coffee bean itself, but only the water solution containing the caffeine that was previously extracted from the coffee bean. Therefore the water decaffeination process is relatively benign. All methods used to decaffeinate coffee are based on equilibrium principles and solvent/solute properties. As such, neither all of the caffeine is removed from the coffee, nor are all of the flavor compounds returned or left in the coffee. The chemical composition of decaffeinated coffee (or decaf coffee) is altered, and therefore the flavor and aroma are changed.Read more
Processing coffee is a lengthy, multi-step process. I used these instructions for what is known as the "wet method," where you remove the beans from the cherries before drying. The traditional Ethiopian way is the "dry method," which dries the beans still in the cherries in big sheets in the sun.
This works best when you've learned at your daddy's knee how to tell when the beans are ready. For the rest of us, the wet method provides more easily observable benchmarks.Read more
Coffee is cultivated in different ways the world over, owing to diversity in local customs, climate and geography. The oldest and most traditional coffee growing methods are still used in parts of Central America and India, where Coffea plants grow alongside other types of plants, at high elevations, sheltered from the sun’s rays.
This is in great contrast to a major producer like Brazil, where intensive, large-scale cultivation relies on sunlight, and where significant investments are required in irrigation and mechanical harvesting equipment. There is greater environmental impact.Read more
Through a mixture of speakers, interactive experiences and opportunities for conversation, Re:co looks at the specialty coffee market, the challenges we face and some of the solutions we have, and also shine a light on opportunities for growth and development and will delve into how these can be approached.
A chemist at the University has teamed up with the UK Barista Champion to find the best type of water for making coffee. The pair are heading to the World Barista Championships in Italy on 8 June to share their coffee chemistry knowledge with the rest of the world.
Christopher Hendon, a PhD student from our Department of Chemistry, embarked on the project in his spare time with friend Maxwell Colonna-Dashwood, owner of Colonna and Small’s coffee shop in Bath, after a discussion about why the taste of coffee varies so much.Read more
Coffee has been for decades the most commercialized food product and most widely consumed beverage in the world. Since the opening of the first coffee house in Mecca at the end of the fifteenth century, coffee consumption has greatly increased all around the world. In 2010, coffee production reached 8.1 million tons worldwide. This represents more than 500 billion cups, with the United States, Brazil, Germany, Japan, and Italy being the major consumer countries.
However, per capita consumption in North European countries such as Finland, Norway, Denmark, and Sweden may reach 8 kg/year, more than two times that of the United States or Brazil. The reasons for this continuous increase in coffee consumption include improved cup quality through selection of varieties and breeding, better agricultural practices; the creation of specialty shops, and a change in coffee’s image through the dissemination of information on the health benefits of long-term coffee consumption. Today, coffee is considered a functional food, primarily due to its high content of compounds that exert antioxidant and other beneficial biological properties. The characteristic flavor and richness of coffee aroma make it a unique beverage, with almost a thousand volatile compounds identified in roasted coffee. The coffee tree belongs to the Rubiaceae family, genus Coffea. Although more than 80 coffee species have been identified worldwide, only two are economically important. Coffea arabica, also known as Arabica coffee, is responsible for approximately 70% of the global coffee market, and Coffea canephora or Robusta coffee (commercial name of one of the main C. canephora cultivars) accounts for the rest [1,5]. Arabica and Robusta coffees are different in many ways, including their ideal growing climates, physical aspects, chemical composition, and characteristics of the brew made with the ground roasted seeds. This chapter will focus on the chemical composition of these two coffee species, including the nonvolatile and volatile compounds important for flavor, quality, and health-promoting actions. To understand the chemical changes that occur during coffee production, we will briefly address the main technological processes green coffee seeds undergo before they are consumed as brewed coffee beverage.Read more
Finca Los Pirineos has produced Cup of Excellence coffees a staggering eight times – four of which they were ranked in the Top Ten. The producer, Gilberto Baraona, is on the board of Project Origin Best of El Salvador Auctions. And the farm uses eight different processing methods on over 90 coffee varieties. Located on the Tecapa Volcano in Usulutan, 1,550 m.a.s.l., Finca Los Pirineos is a model coffee farm/mill. This is how it processes and mills its coffees.
The oldest method in existence, dry/natural processing is also the least complicated and requires the least machinery – in fact, it doesn’t require any mechanical equipment. The cherries need to be dried on beds or patios, where they will stay for days or even weeks, slowly hardening as they lose moisture. The dry pulp is then removed in the mill.Read more
As much as the best baristas in America can control a cup of coffee when the kettles are steaming and the scales are beeping, the fate of a bean is sealed far earlier, while still in its green state some thousands of miles aways. A number of factors result in a bean's suggested notes of caramel, stone fruit, pine nut, and sesame. Coffee flavor profiles have to do with genetic cultivars—Bourbon, Caturra, Castillo, and Gesha all carry distinct tastes. Elevation, also plays a role.
Lower levels of oxygen in the air create a dense, more complex bean. But to tap into those flavors, coffee must first be transformed from its original state, as the seed of a fruit, into a roast-ready green bean. And how producers handle this transition has a lasting effect on the coffee.Read more
Coffee(Coffea arabica L.) is the most important agricultural commodity and beverage enjoyed throughout the world. In Ethiopia, about 25 % of the total populations of the country are dependent on production, processing, distribution and export of coffee. Besides gene tic and environmental factors, the range of cares taken from field to cupping can affect coffee quality. Different studies were conducted to determine those factors. Therefore, the objective of this review is to assess previous work on factors that affect quality of coffee in Ethiopia and to know the research gap on quality of coffee.
Cup quality is a complex characteristic which depends on a series of factors such as the species or variety (genetic factors), environmental conditions (ecological factors), agronomical practices (cultivation factors), processing systems (post harvest factors), storage conditions, industrial processing, preparation of the beverage and taste of the consumer. The environment h as also a strong influence on coffee quality. Pests and diseases attacks can affect the cherries directly or cause them to deteriorate by debilitating the plants, which will then produce immature or damaged fruits.Read more