Coffee is a drink brewed from roasted coffee beans, the seeds of berries from some Coffea species. When coffee berries turn bright red from their original green that indicates their ripeness. They are then harvested and dried. Dried coffee seeds, usually called “beans” are roasted to varying degrees, depending on the desired coffee flavor. Roasted beans are ground and then brewed with near-boiling water to create coffee.
Coffee is bitter, darkly colored, slightly acidic, and has a stimulating effect because of its caffeine content. It is one of the most popular drinks globally and can be prepared and presented in various ways.
The earliest evidence of coffee drinking is in modern-day Yemen in southern Arabia in the middle of the 15th century. Coffee seeds were first roasted and brewed in Sufi shrines similarly to how they’re prepared today to drink. The Yemenis got the coffee beans from the Ethiopian Highlands via coastal Somali traders and began cultivation. By the 16th century, coffee reached the rest of the Middle East and North Africa and later spread to Europe.
The two coffee bean types grown the most are Coffea Arabica and Coffea Robusta. Coffee plants are now grown in over 70 countries, mainly in the equatorial regions of South and Latin America, Africa, Southeast Asia, and the Indian subcontinent.
As of 2018, Brazil was the leading producer of coffee beans, with 35 percent of the world total. Coffee is a major export product as the top legal agricultural export for numerous countries. This article explains how coffee is made by going through the coffee bean roasting and coffee manufacturing process, following coffee’s journey from coffee cherry to cup of coffee.
Green Coffee Beans and Coffee Harvesting
Coffee production starts when the coffee cherries are harvested. Coffee cherries and blossoms grow on small evergreen trees or shrubs. A coffee tree can grow up to 16 feet tall, but they are usually pruned back to between five and seven feet, which is a comfortable height for picking. There are three different ways of harvesting. They are strip picking, machine picking, and hand-picking. Only using ripe coffee cherries is extremely important. Under or over-ripe cherries will add unpleasant notes to the coffee, along with the balance, consistency, and complexity of the coffee flavor being reduced. This means that the way coffee is harvested is quite important.
Coffee pickers also gather information about the coffee plants, such as branch health, leaf health, pest-infested cherries, and early signs of plant disease or fungi. This knowledge is vital for monitoring coffee plant health and coffee quality, and regular crop inspections should be made.
Strip Picking
This method is popular because it quickly harvests coffee cherries and does not require any machinery. As coffee often grows in the mountains, this makes it hard to use machines. The harvester strips the whole branch of cherries whether or not they are ripe.
This makes it a fast method, but it means the harvest is a mixture of ripe and unripe cherries, which means the crop must be adequately sorted before continuing to be processed.
Machine Picking
Machine picking is used less often because flat land is needed to run harvesting machines. However, when this is possible, machine picking is a highly efficient method to use.
Harvesting machines are expensive, however, but overall labor costs are lower as only one person is needed to run the machine. Machine picking is often used in Brazil because of the relatively flat land.
Hand-Picking
Hand-picking is more time-consuming and generally only used by specialty manufacturers. The harvesters pick only the ripe cherries from the coffee tree and leave the unripe ones to mature.
This slower method can take up to 10 harvests to pick all of the cherries from the coffee trees, depending on the farm size. While this is often a more expensive method, the resulting crop will generally be higher quality.
How Coffee Cherries are Processed
After they’re harvested, coffee cherries must be processed. There are a few different drying and washing methods.
Dry Process
The oldest type is the natural or dry method. It is widely used due to the low costs and the limited additional resources required.
With this process, the coffee cherries are laid out in the sun to dry. They are laid out on brick or concrete areas when handled commercially.
The cherries may also be left to dry on the bare ground, impacting the coffee taste. These beans may have the intense and earthy flavor of the soil.
Many manufacturers using the dry method place their cherries on raised beds in thin layers. This reduces the risk of mold growth while the cherries dry. It also ensures that the coffee cherries are dried with all of their layers intact, which results in some fermentation within the bean.
After the cherries have dried, they look similar to raisins. The coffee is then hulled, removing the outer layers. The beans are next sent to a dry mill to be sorted for shipment.
Washed Process
Another popular coffee processing method is the washed or wet process. Manufacturers generally use this method in parts of East Africa and South America. It is not widely used in areas with limited access to water, such as in some areas of Africa.
The ripe harvested cherries are first sent to a wet mill. There, they are loaded and pass through a de-pulping machine, which removes the coffee beans from the cherries. However, the beans are contained in the pulp of the cherry, called the mucilage. It is a sticky substance that contains alcohol and sugar, which impacts the coffee flavor.
After going through the machine, the beans are added to a fermentation tank, where they stay for 12 to 24 hours, depending on the tank temperature. Different fermentation times vary the flavor profile of the beans.
This variation is because the beans that ferment for longer have more time to absorb sugar from the mucilage, making a sweeter coffee. However, if the beans ferment for too long, they can acquire a vinegar-like quality.
During fermentation, the mucilage breaks down, leaving the beans in their parchment. Parchment coffee is the part that has been removed from the outside of the cherry but has not had the protective paddy peel removed. When removed from the tanks, the beans must be washed to remove the parchment coffee, which can be done in a clean water tank or in channels. Afterward, the beans are gritty to the touch and ready to be dried.
The beans are then taken to drying tables or be laid on patios. They dry for 10 to 22 days while being gently turned to ensure that they do not grow mold. Slower drying times will usually create a better balance and complexity to the taste of the bean.
There are also instances when washed beans are mechanically dried. This commonly occurs when the manufacturer does not have the space to air dry the beans. Mechanical drying takes about three days, but does decrease the shelf life of any whole bean coffee.
Wet-Hulled Process
This method is also known as the semi-washed process and is most often used in Indonesia. It starts in the same manner as the washed process, with the fresh cherries being pulped.
The beans will then be partially sun-dried and removed from the drying process when some moisture remains.
The beans are then hulled. This involves tearing off the beans’ outer protective layer and leaving a whitish, swollen green bean behind. The drying of the bean then continues on a patio. The coffee drying process is complete when the beans turn a dark, distinctive bluish-green color.
While this method results in some unique flavors to the coffee, there are risks involved. The early removal of the husk leaves the bean unprotected at a crucial stage, thus allowing the bean to be vulnerable to insects and other elements.
Honey Process
The honey process is considered to be a hybrid process and is open to interpretation depending on the coffee farmer’s aims.
In Brazil, the honey process is closer to the Pulped Natural process. This process requires less water than the washed process. Still, it is also less susceptible to the defects of the natural process. This hybrid process starts with depulping the coffee cherries.
However, instead of being washed to get rid of the mucilage, the beans are sent to dry, resulting in a coffee bean that offers a sweeter taste with more rounded acidity. Many manufacturers think this provides better flavor clarity of the coffee.
In other South American countries, the honey process is different. The process is often considered the true honey process and not a hybrid like the one in Brazil. First, the coffee cherries are depulped in a very controlled manner, leaving a consistent mucilage amount on each of the beans.
Having a consistent amount of mucilage ensures a consistent flavor profile created with the beans. The beans are not fermented as this can vary the taste profile.
The drying process is critical in this type of honey process because the mucilage increases the chances of mold growth. To avoid mold and defective beans, they are turned regularly while drying. The regular turning also protects the beans from insects. This method is also known as the yellow honey process.
Image credit: Shutterstock.com/Sergey_Bogomyako
How Roasting Coffee Beans Works
So how is coffee manufactured? Roasting dried coffee seeds transforms the chemical and physical properties of the green coffee beans into roasted coffee products. The roasting process creates the characteristic flavor of coffee by causing the green beans to change in taste. Unroasted beans contain similar protein levels, acids, sugars, and caffeine as those that have been roasted but have a lack of taste.
The wide majority of coffee is roasted commercially and on a large scale. Still, small-scale commercial roasting has grown significantly with the trend toward “single-origin” coffees served at specialty coffee shops. Some amateurs even roast coffee at home as a hobby and as way of experimenting with the flavor profile of the beans, and to ensure the freshest possible roast.
Roasting comes after coffee processing and before coffee brewing. It involves sorting, roasting, cooling, and packaging but can also include grinding. First, bags or sacks of green coffee beans are hand- or machine-opened, emptied into a hopper, and screened to remove debris. The green beans are then weighed and transferred to storage hoppers, unless it is a small-scale production. The beans are conveyed from the storage hoppers to the roaster.
At first, the process is endothermic, meaning the beans are absorbing heat, but at around 175 degrees Celsius or 347 degrees Fahrenheit, it becomes exothermic as the beans give off heat. This means that due to a chemical reaction the beans are heating themselves, and an adjustment of the roaster’s heat source may be necessary. At the end of the roasting cycle, the beans are emptied from the roasting chamber and are usually cooled by air or water-quenching.
Different Coffee Bean Roasts
Coffee beans lose 15 to 18 percent of their mass during roasting, mainly because of water loss but also because of volatile compounds. However, while the beans experience a weight loss, the size of the beans doubles during the roasting because of the physical expansion caused by an increase in internal pressure from vaporized water.
Many coffee names refer to the various gradations of roast, such as “French roast” or “city roast” for the internal bean temperatures reached during roasting. Recipes called “roast profiles” specify how to attain specific flavor characteristics. A number of factors can help the person roasting determine the best profile to use, such as the coffee’s origin, moisture content, variety, processing method, bean density, or desired flavor characteristics.
A roast profile can be displayed by a graph showing time on one axis and temperature on the other. This profile is created either with manual recording or in larger scale production, by using computer software and data loggers connected to temperature probes inside various parts of the roaster.
The most popular, but perhaps the least accurate, method of determining the degree of roast is to judge the bean’s color by eye. As the green coffee beans absorb heat, the color turns yellow and then to increasingly darker shades of brown. This is actually how the names “light, medium, and dark” for types of roast came out. In the later stages of roasting, oils materialize on the surface of the bean.
Lipids present inside coffee seeds liquify from the heat and pressure built up in the bean. These lipids can usually be seen on the bean surface. The roasted beans will continue to darken until removed from the heat source.
Coffee beans also darken as they age, making color alone not enough to use as a deciding factor on when to stop heating. Most roasters use a combination of temperature, color, smell, and sound (the beans make a cracking noise as they roast) to keep track of the roasting process.
Because lightly roasted beans aren’t left on the roasting machine for as long as dark roasted beans, they have more internal moisture and are denser. Denser coffee beans have more caffeine, more brightness/acidity, and a more fruity flavor. The body or texture of the coffee is thinner than that of a dark roast and is similar to a tea in its thickness.
Dark roast coffee beans stay on the roasting machine for a longer time or at a higher temperature. This means the beans will lose more moisture, making them less dense, less caffeinated, and more single-note in flavor. Dark roast is typically considered more bitter with a smoky taste.
If the coffee is going to be decaffeinated, it is processed using either a solvent or a water method. The beans are treated with a solvent, usually methylene chloride, that leaches out the caffeine with the solvent method. If this decaffeination method is used, the beans must be thoroughly washed to remove traces of the solvent before roasting. The other method involves steaming the beans to bring the caffeine to the surface and then scraping off this caffeine-rich layer.
After Roasting
Before the whole coffee beans or coffee grounds are packaged, they are stored in a highly controlled environment. Humidity, heat, air, and light must all be watched closely to ensure quality and to avoid deterioration. Since freshly roasted beans make the best coffee, the right kind of packaging is crucial to ensure high-quality freshness.
This is a difficult decision for coffee manufacturing companies, and many different packaging products are available for packaging coffee to be sold. The goal of any packaging is to reduce the amount of time it takes for the coffee to become stale.
There are many different coffee brewing methods. Almost all forms of preparing coffee require the grinding of beans and then mixing them with hot water long enough to let the flavor emerge but not long enough to create bitter tastes. The liquid coffee is consumed after the spent ground coffee is removed.
Brewing method considerations include the fineness of grind, how the water is used to extract the flavor, the ratio of ground coffee to water, additional flavorings such as milk and sugar, and the technique being used to separate spent grounds. Brewing methods include pour over, French press, moka pot, drip coffee, siphons, cold brew, and aeropress.
Instant Coffee
Many products are sold for the convenience of consumers who do not want to take extra time to prepare their coffee or who don’t have coffee making equipment. Instant coffee is made of granules quickly dissolved in hot water. Originally invented in 1907, it rapidly gained popularity in many countries in the post-war period.
Many consumers decided that the convenience of a cup of instant coffee made up for any perceived inferiority in taste, although, since the late 1970s, instant coffee has been produced similarly to the taste of freshly brewed coffee. Instant coffee is made by either freeze-drying or spray drying, which then can be rehydrated. Instant coffee is also manufactured in a concentrated liquid form.
These liquid coffee concentrates are typically used in large institutional situations where coffee needs to be made for thousands of people simultaneously. It has a flavor about as good as low-grade robusta coffee, and costs about 10 cents a cup to make. The coffee machines can process up to 500 cups an hour.
Conclusion
Above, we have explained how coffee is manufactured by harvesting, drying, and roasting coffee beans. We hope this information has been helpful to you in your supplier search. To learn more about these companies, or to make your own custom shortlist of suppliers, feel free to visit Thomasnet.com, which has information on other similar products.