This past summer, a visiting friend brought me a bag of Guatemalan coffee. In early fall, I met a local roaster who personally visits Nicaragua each year to select his coffee beans. As winter closed in, I purchased a bag of freshly roasted Ethiopian coffee beans from a favorite coffee shop.
I was surprised that, even as just a “coffee hobbyist,” I could clearly taste distinctions between these coffees and the Columbian coffee I have enjoyed through most of my coffee drinking years. All of which got me thinking about the “bigger picture” of coffee growing around the world. Why is it that coffee from one region tastes so noticeably different than coffee from another? What factors contribute to these differences? And how do we discover which part of the world produces the coffee we like best?
The Coffee Belt
Coffee is grown predominantly around the central circumference of the planet in an area referred to as either the “coffee belt” or “bean belt.” Sitting between the Tropic of Cancer and Tropic of Capricorn, this equatorial swath of the globe provides the most favorable conditions for coffee growing and harvesting. As noted in the article Where is the Best Coffee Grown, areas without threat of frost and abundant rainfall harvest coffee beans twice per year. On coffee farms that are further from the equator or at higher elevations — places where cold and frost can be a concern in winter months and distinct “dry seasons” exist — coffee is harvested only at the end of summer.
Primary Coffee-Growing Regions
There are over 70 countries that produce coffee within the Coffee Belt. Some — like Brazil, Vietnam, Columbia, Indonesia and Ethiopia — are major coffee suppliers to the world, exporting hundreds of thousands of tons of coffee beans each year. But a lot of coffee comes from countries with lower production rates. Rather than trying to keep up with every individual country, we more often refer to coffee origins in terms of one the five major regions in which they are grown:
- Central America
- North America / The Caribbean
- South America
- Southeast Asia
Within each of these broad regions, there are a variety of factors that influence both the character and quality of the coffee beans produced. This, in turn, affects the taste of the brewed coffee in our cups. Some of these factors are natural while others are dictated by human action.
Nature’s Influence on Coffee Growing
A variety of natural factors affect the final character and quality of the cup of coffee we drink. Some of these determinants are specifically related to the topography and climate of the growing region while others are dependent upon the type of coffee plants being grown and the farming method used. Here’s a brief look at how nature itself influences the taste of your morning brew:
Elevation: The elevation at which coffee plants are raised create an array of nuances in the bean and, therefore, the taste in the cup. Very simply put, growing conditions deteriorate the higher up coffee is planted. This results in slower growth and smaller cherries (the “cherry” is the plant’s fruit that contains the coffee seed, which we refer to as the coffee bean).
Why is this significant? Because a slower growth rate allows time for an increased concentration of sugar to develop in the coffee bean. This added natural sweetness, as far as most people’s taste buds are concerned, positively affects the bean’s flavor composition.
Further, a slower-growing and, therefore, smaller cherry means there is less moist, fruity pulp surrounding the coffee seeds. The resulting beans, therefore, are harder and denser with a more concentrated and complex flavor make-up than beans grown at lower elevations.
Although the following breakdown overly simplifies the matter, it will give you a very basic idea of the flavor characteristics that are found at various elevations of coffee growing:
- Low Altitude (2,500 feet or less) – Mild, earthy, somewhat bland
- Medium Altitude (3,000 feet) – Smooth and slightly sweet
- High Altitude (4,000 feet) – Citrusy with vanilla, chocolate, and/or nutty overtones
- Very High Altitude (5,000 feet or more) – Spicy with fruity and floral notes
So now we understand why gourmet coffee roasters include elevation on their packaging!
Soil: Coffee plants require a dense core of basic nutrients to mature, thrive, and produce beans with desirable flavor characteristics. These nutrients are found most readily and abundantly in volcanic earth, the texture of which also allows for good water drainage that keeps the coffee plant’s roots from rotting. This is why so many coffee farms are situated on volcanic mountainsides.
While there are too many nutrients that affect the health of coffee plants to discuss them all, a few are worth noting for the part they play in our coffee-drinking experience. Potassium levels in the soil, for example, impact the levels of citric acid and sugar in the bean. Nitrogen levels influence, among other things, caffeine level. And one of the responsibilities of boron is cell division, which ultimately means peaberry coffee exists primarily due to inadequate boron levels in the soil.
When all is said and done, soil content so intricately affects coffee production that coffee beans from the same plantation often have noticeably different flavor markers. Regional soil composition plays a huge role in the taste variations we find in our coffee cup.
Temperature: The ideal temperature range for growing Arabica coffee is 73 – 83 degrees. Robusta coffee can tolerate slightly warmer temperatures (we’ll discuss the Arabica and Robusta plants in more detail in a moment). Coffee plants can withstand cold temperatures, but they are destroyed by frost and freezing. This is the primary reason coffee farming is limited to the warmer equatorial “bean belt.”
As with elevation, the growing-season temperature will affect how slowly or quickly coffee cherries grow and how fully they develop. Varying rates of growth allow for — or prohibit — varying flavor markers to develop within the coffee beans.
Rainfall: Coffee plants require an abundance of water — 60 to 80 inches per year — to thrive. Irrigation is required in areas receiving significantly less rainfall. In warm equatorial regions with continuous rainfall, coffee plants bloom year round and provide two coffee harvests per year. Sub-tropical regions with a denoted “wintry dry season” will have one coffee harvest per year.
Once again, rainfall will affect overall growth rate and bean size, and taste factors within the beans will adjust accordingly. Beans from the same region, and even the same plantation, can vary in flavor from season to season if rainfall totals vary significantly.
But it isn’t just the volume of water that matters. Rain also tends to lower the temperature in the growing fields. Coffee plants experiencing rain-cooled temperatures will mature more slowly. The resulting beans will tend to be sweeter and will brew a cup of coffee that’s full in body and complex in flavor.
Type of Coffee Plant: Arabica coffee (coffea arabica) makes up 75-80% of the world’s coffee production, and Robusta (coffea canephora) makes up most of the balance. This is not, as one may guess, because Arabica coffee is easier to grow.
Quite the contrary.
Arabica coffee is a far more finicky a plant, requiring ideal geographic and climatic conditions to thrive. It’s also far more susceptible to the blight of harmful insects and produces fewer coffee beans per plant.
So why is so much more Arabica coffee grown than Robusta? In a word: Taste!
Although Robusta coffee plants grow better in a wider range of climatic conditions than Arabica, are less prone to infestation, and provide a greater crop yield per plant, the Robusta bean, unfortunately, produces a very bitter cup of coffee.
That said, finer Robusta still has its fans among those who prefer a dense, very robust cup of coffee, meaning, primarily, espresso aficionados. It’s finely-ground Robusta coffee, comprising 10-15% of an otherwise Arabica-based espresso blend, that provides the full-bodied taste, heftier “feel” on the tongue, and best crema (foamy head) of a great espresso.
Otherwise, Robusta is generally used as an inexpensive “filler” for cheaper coffee brands. Any high-quality gourmet coffee is going to be produced using much-less-bitter Arabica coffee.
Farming Method: Traditionally, coffee growing took place under the canopy of trees because this is where wild coffee grew best. The plants remained sufficiently warm due to the overall climate but were protected by the forest from intense direct sunlight. Moisture was retained well beneath the trees, and decaying leaf matter kept the soil nutrient-rich.
The intentional planting and cultivation of coffee beneath tree cover is now referred to as “shade farming.”
As coffee’s popularity exploded over the past century, the yields of shade-farmed coffee could not keep up with global demands. Therefore, in the 1970s, hybridized sun-tolerant coffee plants were developed. While the aim might have been noble enough — to create higher-yield coffee plants with greater resistance to fungal diseases that could caffeinate the planet at a reasonable cost — the consequences have been ecologically devastating.
As forests were cleared to make way for full-sun coffee farming, the biodiversity of these regions was also destroyed. Birds, insects, mammals, and plants were all displaced, and the natural, self-sustaining cycles of the ecosystem were obliterated. Natural water retention, soil nutrient replenishment, erosion, and insect predators all were compromised, meaning full-sun coffee farming is only successful when imbued with systematic irrigation and high-volume fertilizer and pesticide use.
As far as flavor goes, there isn’t much difference between farming methods. Great-tasting coffee is produced by both traditional shade farming and full-sun farming. And scientific studies show that little pesticide residue remains on roasted coffee beans to be a health concern. So the primary considerations over farming methods come down to crop yields and sustainability, and we’ll be exploring these important issues in-depth in an upcoming article.
For now, we’ve clearly identified a wide variety of ways nature determines the way our coffee tastes. But this isn’t the whole picture because wherever man is involved, man also influences. And man definitely influences the flavor of coffee.
The Human Element
Before we look at the ways humans influence the taste of coffee, we need to keep in mind that, in this article, we’re referring only to the regional flavor markers of raw, green coffee beans. This is the essence that exists in the coffee beans before the roasting, grinding, and brewing, all of which, of course, create their own nuances of flavor. Our focus here is on the factors that differentiate one regional coffee’s taste from another. And the “human element” that comes down to is processing.
There are two predominant methods of processing picked coffee beans, the wet method and the dry method. There’s also a less-common semi-dry process that combines elements of both the wet and dry methods. Additionally, some regions actually age their raw coffee beans before distribution which allows the development of unique flavor markers that cannot be duplicated by other means.
Wet Processing: The wet or “washed coffee” method of preparing raw coffee beans for general use begins with an immersion. All of the picked coffee cherries are placed in large vats of water. Here, unripe fruit and harvesting debris will float while the denser, ripened cherries will sink. This make for easy selection of the best coffee fruit.
The sorted ripe coffee cherries are then pressed through screens which roughly begins the process of separating the fruity pulp from the coffee beans.
The next step, fermentation, will remove the rest of the pulp from the beans. During this stage of wet processing, the coffee cherries are either immersed again in water or allowed to ferment in their own juices. Enzymes are then mixed in to help break down the cellulose surrounding the beans.
After fermentation, the coffee beans are thoroughly washed again, and then dried. Drying may be accomplished by sunlight, by machine, or a combination of the two. Once the beans have been dried to a moisture level of about 10%, they are placed in a hulling machine. This removes the last, now-crumbly layer of parchment surrounding the beans.
Variances in the washing methods, as well as the type and duration of the fermenting process, have significant impact on the coffee’s ultimate flavor. Some African coffees, for example, owe their unique flavor markers to the fact that the beans are fermented for nearly a week. Most processors ferment for only 24-36 hours.
Generally speaking, wet processing results in a light-bodied beverage with fruity overtones and notable acidity.
Dry Processing: In the dry processing method, harvested coffee cherries are first sorted by hand to retain only the ripest, most perfect fruit. The coffee cherries are then spread out upon special brick or concrete slabs or woven mats and left to dry in the sun.
The drying process can take up to four weeks and requires continual monitoring until proper moisture content is reached. Once dried, the coffee cherries are put through a hulling machine that separates the outer layers from the coffee bean in one step.
Although it seems a simpler method — and it is, indeed, the oldest coffee processing method — dry processing is actually more labor-intensive than wet processing since the initial sorting of the coffee cherries must be done by hand. The dry processing method obviously does not require the vast amounts of water necessary for wet processing, however. This makes it a better processing method for more arid climates or drought-prone regions.
It’s no surprise that, between their weeks spend drying in the sun and their lack of a fermentation process, dry processed coffee beans develop different flavor markers than their wet-processed counterparts. In the cup, this typically translates into a slightly sweeter, full-bodied brew and nutty overtones.
Semi-Dry Processing: This final processing method, sometimes referred to as “honey processing,” combines a bit of both the wet and dry processes previously explained. First, the outer skin of the ripe coffee cherries is mechanically removed. The beans then “rest” for a day before they are washed in order to remove the outermost mucilage. The partially-hulled coffee is then dried to about a 10% moisture content.
Since there is a “sugary” layer still attached to the beans when they are placed in the sun for drying, they are at increased risk for developing bacterial and fungal issues. The beans are also prone to fermentation at any point throughout the drying period. All of this means that the beans must be moved consistently multiple times per hour throughout the entire drying process to thwart any of these crop-ruining issues.
What makes this labor-intensive process worthwhile, however, is that the coffee beans ultimately take on the best qualities of both the wet- and dry-processed coffees. In the cup that translates into a beverage with a full, syrupy body, enhanced sweetness, and mild but noticeable acidity.
Aging: Usually when we think of “aged” beverages, we picture wine or other spirits in mellowing in big oak casks in darkened cellars. But there are aged coffees, as well, though it’s the raw, green beans that are aged in this case and not the brewed liquid.
Aged coffee actually makes perfect sense if we consider a bit of coffee’s history. In the early days of coffee trading, bags of raw coffee beans would spend weeks, if not months, stored on the ships that were transporting them from Yemen to European ports. On these journeys, both time and exposure to salty sea air altered the flavor of the coffee beans.
Eventually trade routes were significantly shortened by the opening of the Suez Canal. Which meant coffee shipments reached their destinations much more quickly. But it also meant that the delivered coffee beans now lacked that “aged” taste to which its devoted drinkers had grown accustomed. To try to placate the coffee lovers who weren’t happy with the taste of the fresher beans they were now receiving, some growers began purposely aging their coffee beans in port-side warehouses for periods of six months or more before transporting them for use.
Aged coffee also developed as a byproduct of basic supply and demand. If a grower found himself with too much coffee, he might store if for a time to sell at a later date. He might do the same simply to wait for a higher selling price.
These days, freshness reigns, and most coffee experts agree that fresh coffee beans are truly the best beans. That said, however, aged coffee beans are still produced, and they create a unique taste experience that can’t be duplicated by any other process.
When beans are aged, they generally create a brewed cup with fuller body and less acidity. The way the beans are aged will create the most telling flavors, however. Beans aged traditionally — slowly in moderate humidity — will become sweeter and somewhat syrupy but will retain a clean taste. Where aging is accelerated by exposing the beans to high humidity, however, the resulting coffee will have a far more earthy, pungent taste.
From Around the World to Your Cup
Now we have a general understanding of why coffee from the various growing regions taste so different. But how do we go about finding which regional flavor is our favorite? In my opinion, there’s only two ways: through knowledge and exuberant experimentation.
Over the next few weeks, I’ll be posting articles that will explore in greater detail specific coffee-growing countries around the world. We’ll learn about the history and coffee culture of each area, examine how the climate and topography impact their coffee growing practices, and discuss the processing method or methods used.
With that knowledge, we’ll be able to get a lot more specific about the quality of the coffee produced in each region. And, whenever possible, I’ll do some “regional taste testing” so I can share with you my taste buds’ opinion on the matter.
Please accept this as your formal invitation to do a little world traveling with me, all from the comfort of your own home in the good company of your favorite coffee mug. Our first stop: Africa
Do you have a favorite regional coffee? Or is there one you’ve always been curious about? If so, let me know in the comments section below, and we’ll travel there soon.