There is a lot to know about coffee. GPC roasters and baristas are self professed coffee geeks, and are constantly seeking out new information on the subject. The more we learn, the more we know that we have only scratched the surface. While we could never hope to provide a definitive source for information on coffee, we hope this section of the website will give you some background information and, most importantly, whet your appetite to learn more.
Here you will find a brief history of coffee and learn about how it is grown and roasted. You will also learn how to store and brew your coffee once it is in your possession (to find some excellent coffee, be sure to check out our online store.)
There are numerous options for brewing coffee at home, but for retail applications options are limited. Most businesses use the typical Bunn style automatic drip machine. In order to achieve the best taste possible on your equipment, consider these guidelines:
According to legend an Arabian goat herder named Kaldi found his goats dancing joyously around a dark green leafed shrub with bright red cherries in the southern tip of the Arabian Peninsula. Kaldi soon determined that it was the bright red cherries on the shrub that were causing the peculiar euphoria; and after trying the cherries himself, he learned of their powerful effect. The stimulating effect was then exploited by monks at a local monastery to stay awake during extended hours of prayer and distributed to other monasteries around the world. Coffee was born.
During the Ethiopian invasion of southern Arabia in 525 AD, coffee berries were brought to the Arabian Peninsula to what is today the country of Yemen. Thus the first true cultivation of coffee began in the sixth century on. Arabs consumed coffee as a fruit, boiled it with water to make a beverage. When the coffee seeds were transported to Turkey, they were roasted for the first time over an open fire.
Coffee came to the European continent by means of Venetian trade merchants around 1615. By 1763, there were over 200 coffee bars in Venice alone. It was in the early 1700s that a French infantry captain brought the first coffee plant to the New World, which he planted on the French-colonized island of Martinique, in the Caribbean.
Espresso is a fairly recent innovation that was originated in France in 1822. Italy refined and perfected the espresso machine. Espresso is a way of life in Italy to the extent that cafe prices for coffee are regulated by the Italian government. There are over 200,000 coffee bars in Italy today. Presently, coffee as a world commodity is second only to oil.
The green coffee bean, like other nuts, kernels and beans is a combination of fats, proteins, fiber and miscellaneous other substances. The aroma and flavor of coffee appears only when heat is applied to the bean simultaneously drawing out the moisture and base matter in the beans a volatile, oily substance variously called coffee essence, coffee oil, or coffeol. It is a fragile substance that evaporates easily and absorbs less undesirable flavors. Without this, there is no coffee, yet it constitutes only 0.5% of the weight of the bean.
As the bean is held in the roaster for longer periods and more moisture is lost, the oil develops further and some begins to rise to the surface of the bean, giving dark roasts their characteristic lightly slick to oily appearance.
Beneath the oil, the hard matter of the bean begins to develop a slightly burned flavor while the sugars caramelize, which together help create the bittersweet tones so attractive to dark-roast aficionados. When most of the sugars have been burned off the resulting roasted coffee is called French or Italian. Darker roasts contain a touch less caffeine than lighter roasts. Coffees are roasted across the whole spectrum of where moisture and the coffee oils are released.
A cup can range from enlightening to frightening. The beans can come from a seemingly endless range of locales. Roast color can fall anywhere between light cinnamon to charcoal black. The coffee world is, if anything, one of variety. Understanding what makes coffee taste the way it does, and what makes each coffee unique from all the others is a vital step towards better appreciating this mysterious beverage.
Factors influencing the quality and flavor of coffee can not be counted. The local climate, seasonal weather patterns, soil composition, botanical variety, ripeness at picking, processing practices, roast profile, brewing technique, storage conditions and blend composition are only the beginning of an incomplete list of variables. Most are not fully understood, but our collective coffee knowledge has exponentially grown in recent years, and some light has been shed on what practices tend to produce the best cup. By dissecting this path from origin to palate, coffee can only come closer to realizing its full potential.
All coffee comes from plants of the genus Coffea, which is comprised of 10 species, only two of which are of relative importance. The first, Coffea Canephora, or Coffea Robusta, comprises only a small portion of the worlds coffee supply, with estimates ranging from 10 - 30%. Robusta trees are resilient, adaptive, and high yielding. The species typically produces beans of inferior quality, best suited for use in instant coffee, or commercial blends striving for economy. High quality Robusta does exist, however, and is valued by some as a component in an espresso blend, where it can produce visually impressive crema and assert its flavor in large amounts of milk.
The second species, and the one most valued by today's specialty coffee industry, is Coffea Arabica. Coffea Arabica produces all of the worlds best coffee. It is less productive, more disease susceptible, and generally more difficult to grow than its sibling, but rewards the careful farmer with a higher quality crop, shining with the distinct, delicious flavors coffee lovers desire.
Within the species, there are many botanical varieties each with their own unique characteristics. Many, like Bourbon and Gesha, have been around for well over a hundred years. Others, like Catimor and Ruiru 11, are the intentional result of breeding programs aimed at producing hardier or higher yielding plants. These hybrids often contain a portion of other species in their pedigree, but are, for all practical purposes, considered Arabica. Botanical varieties vary in many aspects, and cup quality is no exception. The lower yielding heirloom strains usually produce the superior cup.
The farm is the true birthplace of quality coffee. If grown in the wrong place, cultivated poorly, or processed without care, no amount of roasting skill can fix a bad coffee. Great coffee can only be grown at the greatest farms.
The first criterion for a great farm is location. High Altitude and low light intensity (shade) seem to be two of the most important aspects. Coffea Arabica can only produce beans with ample acidity when grown at elevation, and shade promotes a longer ripening cycle which allows more time for flavor development. Soil composition also plays a role, with high fertility and adequate drainage as necessities. Even within a given farm, different plots of land can produce distinctively different coffees. Every hillside has its own micro-climate, each with its own unique combination of sun exposure, grade, drainage and elevation.
In any location, coffee requires attentive cultivation to attain the best quality. Farmers must fertilize carefully, prune their trees with skill, and make sure that their crop is harvested at ideal ripeness. Every branch of a coffee tree has dozens of cherries, each ripening at it's own pace. Skilled labor is essential, as only the ripest cherries should be picked. Under-ripe cherries yield beans with tart, harsh acidity and under-developed flavors. Over-ripe cherries can have off flavors of rotted fruit or mold, and lack acidity.
Once picked, the cherries are sorted a second time to remove sticks and other artifacts, and to screen out less than ideal fruit. They can then be processed in one of several fashions. The simplest method is known as the natural or dry process, and often takes place on the farm. The ripe cherries are sun-dried on tables or patios over a period of one-four weeks. The fruit is raked frequently by hand to insure even drying and to prevent mold from forming. Improper dry processing leads to a moldy, offensively earthy flavor profile, but when executed well, can produce some of the most fruity and complex coffee imaginable.
The second method is known as the wet process, which usually takes place at a processing mill away from the individual farms. In this process, the beans are removed from the fruit before drying. First, the outer skin is stripped from the cherry by pressing the fruit through a screen with running water. The remaining fruit pulp is removed either mechanically, or enzymatically through fermentation in large tanks of water. Once the fruit pulp is freed from the bean, the coffee is dried in a manner similar to dry processing, leaving the last layer of parchment intact. When done properly , the wet process results in a classic clean and bright flavor profile. If mistakes are made, however, the resulting coffee can have a variety of taste defects.
After the wet or dry process is complete, the remaining layers of dried fruit or parchment are removed, and the coffee is sorted. On some larger farms, machines detect and remove defective beans, but in most cases this is done by hand. Broken, discolored, undeveloped, misshapen, and insect damaged beans are just some of the defects that are usually removed.
Different origins have different standards for sorting. Dry processed Yemens, for example, are usually left with a large percentage of defects, while a washed coffee from Guatemala will be meticulously sorted to produce a very homogeneous lot with very few defects. In some origins, certain defects are appreciated for their distinctively wild flavors, but in a coffee striving for purity and cleanliness, they are entirely unacceptable.
Once sorted, the green coffee is bagged for shipping in a large burlap sack, usually weighing about 150 pounds. Some quality concerned processors have begun packaging their coffees in a plastic bag with a one way valve, but this is far from common. The air tight bags keep the coffee tasting its best for a significantly greater amount of time, but is more expensive than the standard burlap.
The best thing that can happen between bagging and roasting is for the coffee to rest quietly for several weeks in a temperature and humidity controlled environment. This process is almost always interrupted by several transports, by sea, land, and sometimes air. The coffee must move from exporter to roaster, often with several other middlemen in between.
Transit and storage conditions are often less than ideal. Too much or little humidity, high temperature and fluctuation in temperature can all drastically affect the quality of the green coffee, but a good importer ensures that their coffee is cared for properly. Coffee should arrive at an importers holding warehouse within a month or two months of processing, and should make its way to the roaster shortly thereafter.
Green coffee should be roasted within one year of harvest; Most coffees are at their best within six months. As a coffee gets older, acidity and positive flavors decrease, and it can take on a hay-like, cardboardish flavor profile coined "bagginess." This defect is caused by degradation and oxidation of flavor compounds, fats in the beans absorbing aromas from the burlap sack, and changes in moisture content. "Baggy" flavors are a hallmark of coffees past their prime, and can completely ruin an otherwise good cup.
A roasting company's first task (and one of the most important) is to seek out those coffees which meet their standards. Roasters request samples from a number of brokers (who are typically importers as well), roast them all with a similar profile, and carefully taste them side by side. At the cupping table, they must pay close attention to positive and negative flavor attributes and aromas, balance between the various attributes, and consistency from cup to cup. Many coffees are riddled with defects that may affect only one out of every five, ten, or twenty cups, but a good roaster will pass on these lots, and wait for something that tastes consistently excellent.
Once a roaster finds a coffee they want to carry, they will purchase it from the broker, and have it shipped to their roasting facility. Upon arrival, care must be taken to store it properly, following the same guidelines importers adhere to. Inventory control is incredibly important at this stage, and roasters should roast their green coffee within 3-6 months of arrival. Waiting any longer can bring on the tired, baggy flavor profile of past crop coffee.
For every coffee in their inventory, a roaster must determine a suitable roast profile. A roast profile encompasses not only how light or dark a bean will be taken, but how it gets there, in terms of time, temperature, and air flow. For a new coffee, multiple sample roasts will be undertaken, each following a different roast profile, and the results will be tasted side by side to determine what is the best route to take. Deciding exactly how to roast a coffee can take days or weeks, as the roaster fine tunes the process and makes minute profile adjustments until the bean's full potential is realized.
Degree of roast is dictated by the temperature at which the operator halts the roasting process and begins cooling the beans. This can range from the light, mottled cinnamon color which is observed around 415 degrees F, up to a dark "french roast" stage which can approach 470 degrees. There isn't one degree of roast that is the best for every coffee, but in general, lighter roasts (410 - 440 degrees) favor the unique qualities and intricate aromas developed within each bean at origin. As a coffee is taken darker, origin character is lost (along with acidity), and smoky "roast flavors" become more prevalent. As temperature climbs past 465 degrees, flavors of carbon and smoke are about all that remains, with very little supporting acidity or sweetness.
The process of sampling, tasting, and creating a roast profile happens on an ongoing basis. New coffees come in weekly or monthly, and roast profiles must be continually updated for each coffee as it is used. Minute changes occur as the green coffee gets older, and must be compensated for by changes in the profile.
After roasting, coffee should be held in airtight containers, away from warm temperatures and light, and consumed within several weeks. Coffee is at its prime within 7 days after roasting, and will ideally be sold to customers within this time frame. Most consumers will notice very little change in quality for 1-3 weeks. Beyond this time frame, the beans will lose much of their aroma and acidity, and can begin to taste tired, boring and stale. Any longer than one month, and the oils within the beans can go rancid, leaving very little left to desire.
If coffee is ground before storing, these changes will proceed much more rapidly. The ground particles have a much greater total surface area than whole bean coffee; Oxygen permeates the coffee much more quickly, while trapped CO2 and aroma molecules rapidly dissipate. Ground coffee will lose a perceptible level of aroma within hours, and will usually begin to taste stale within one day. Coffee should only be ground immediately before brewing.
Brewing is the last step in the process, and the last chance for something to go wrong. It can be a very simple process, requiring little more than a good grinder, clean water, and careful hands. With a little attention, brewing can transform a high quality bean into an amazing cup of coffee.
There are dozens of brewing methods available, ranging from a simple manual drip cone, to the complex, finicky espresso process. With the exception of espresso, all of the methods are fairly easy to execute at home, and can produce a quality cup with minimal effort. Most brewing methods have similar requirements and challenges, and all of them require a good burr grinder.
The grinder is the most important piece of equipment in the process, and can make or break the cup. Cheap blade grinders pulverize beans into pieces varying greatly in size, and are not capable of properly grinding coffee. A high quality burr grinder cuts the beans more evenly, grinds slowly without creating a lot of heat, and results in a dramatically better cup. It is nothing short of a requirement for brewing acceptable coffee.
Two of the best brewing methods for the home are manual drip and french press. Both are economical, relatively easy to use, and capable of producing a very good cup. Automatic drip brewers are more commonly used, but are much more costly. All but the most expensive models heat the water inadequately, rely on a hot plate to keep the coffee warm (heating brewed coffee creates bitterness), and brew an inferior cup.
With any brewing method, equipment must be kept very clean, and quality water must be used. Tap water will suffice in areas where it tastes relatively neutral, and pour over filters can help eliminate any offensive odors (some high end brewers incorporate water filtration). Where the quality of tap water is unacceptable, bottled spring water is a good option. Distilled or reverse osmosis water, however, is actually too pure to brew the best coffee. A fair amount of mineral content is a good thing to have, as it positively interacts with the grounds during brewing.
Brewing coffee in a commercial setting requires a greater level of care and attention. The importance of grinder, brewer, and air pot cleanliness can not be stressed enough, and grinder burrs should be changed regularly. Dull burrs create heat, and can quickly stale or even burn the coffee before brewing. In any setting, brewed coffee should be served as fresh as possible, or within 30-60 minutes.
With all of the things that can go wrong in the process, it becomes easy to see why there is so much bad or mediocre coffee being served today. If it isn't a low grown bean from a high yielding hybrid, chances are it was roasted too dark or sold outside of the freshness window. The best way to find good coffee is to try what's readily available, and dismiss anything less than delicious. Finding good coffee is no easy task, but if it isn't available locally, there are a variety of excellent mail order companies willing to ship to just about anywhere. Brewing coffee at home is very easy, and with a good bean, the results can be just as good as what is available at a top-tier cafe.
When all of the right things happen at each stage in the process, and coffee is given the attention it deserves, the result can be truly remarkable. A great cup of coffee should be sweet, balanced, and unique. It should change as it cools, continually revealing new flavors and aromas. It can be an enlightening experience for someone who is used to supermarket or restaurant coffee, and it is a shame it is so rare.