Volcanoes can be costly. The Kilauea eruption of Feb 28, 1955 destroyed 21 houses, 10km of road, 4000 acres of sugar plantations and one coffee plantation: the damage was 40 million dollar in today’s prices. The cost of Mount St Helens was 1 billion dollar. Both events were eclipsed by Eyjafjallajokull: its price tag of 5 billion dollars was almost entirely due to the flight ban. Eruptions in poorer countries are cheaper, but can still cost the local economy hundreds of millions of dollar. Volcanoes may not be the most expensive environmental hazard (hurricane Sandy cost the US 65 billion dollar), but they are nonetheless a risky possession.
But all volcanic damage is recovered by a single product. The world spends 90 billion dollar each year on coffee, a crop that for quality depends on those volcanoes. For developing countries, coffee is the second most valuable export (after oil, based on data from 2000. This statistic is often misquoted as coffee being the second most traded commodity in the world – it is about number 110 by this measure, still respectable for a snack.) Over 75 million people, many in rural, low income areas, owe their employment to coffee. But, just as you can’t make an omelet without breaking an egg, you can’t grow coffee without breaking a mountain.
The plant and its origin
The word ‘coffee’ immortalises the kingdom of Kaffa. It was located in the southwest of current Ethiopia; the local people were known as Kaffichos. Here the coffee plant was first domesticated, sometime before 1300 AD. Southwest Ethiopia is one of eight areas in the world where agriculture was developed independently, and it has had some unique crops. For instance, ensete, a banana like plant of which the tuber is eaten, was domesticated here. From Kaffa, coffee cultivation spread north-east to Harrar. From Harrar the coffee plant was taken to Yemen. This may have happened as late as 1400 AD: the oldest known references to coffee drinking date from around 1450. It became used as a stimulant, and the growing of coffee bushes spread rapidly in Yemen during the 15th century. The rest is history!
(As an aside, this history is not universally accepted. Some people argue that the word coffee comes from an arabic word for ‘wine’, or from a semitic word for ‘dark’. Others argue that the word ‘bun’ used in a 10th century document refers to coffee, either the bean or the tree. Both seem speculative. There is general agreement that the story about an Ethiopian sheep herder discovering coffee by seeing his sheep eat the fruits and becoming more active as a result is mythology.)
The plant family which includes coffee is found in tropical Africa, Madagascar, the Comoros, and the two volcanic islands Mauritius and Reunion which were seeded by plants from Madagascar. The genus ‘Coffea’ contains 125 separate species, most of which are evergreens hiding in humid tropical forests. Only three of the species are used for coffee: Coffea canephora, Coffea arabica and Coffea liberica. Coffee is now grown on every continent, except for Europe which is too cold and Antarctica which is even colder.
Coffea arabica accounts for over 60% of the world’s coffee. It is a natural hybrid, but the parentage is a bit uncertain. One parent is probably C. eugenioides (a rather variable plant from the highlands of Rwanda, Uganda and Kenya), but some genetic evidence suggests a closely related but different species, perhaps C. brevipes (Cameroon) or C. anthonyi. The second parent is probably C. canephora, but may also be a related species such as C. congensis. C. arabica has limited genetic diversity, and the hybridization may have been a relatively recent accident which happened only once.
Coffea arabica is self-pollinating and therefore malleable. Selective breeding over more than 500 years has yielded many different varieties. However, the plant is not particularly strong, perhaps because of the lack of genetic diversity and selective breeding, and can suffer badly from disease. A major outbreak of the coffee rust fungus in Indonesia wiped out much of its arabica plantations in the late 1800’s. C. canephora, at that time known as C. robusta, was found to be a much stronger, disease resistant plant, and was planted instead. It produces a lesser quality coffee. Coffee made from C. canephora is still known as robusta coffee. The Indonesian tests also found that C. humilis (a dwarf species from the Ivory Coast) had a very good, sweet coffee bean, but subsequently this plant disappeared from the test collections.
The coffee family
Coffee comes in five main types, each of which has many different varieties, shown in the coffee tree figure above. The five types are:
From these five types stems a rich variety of coffees, some excellent, some with an impressive name, and a few with both. Blue Mountain is a well-known Typica (arabica), grown in Jamaica. Colombia is a hybrid robusta-arabica originally from Timor; the robusta parent makes it suspect to some afficionados. Red Bourbon is not surprisingly a Bourbon (the colour refers to the bean: other colours also exist). Peaberry is not a particular variety but a bean shape: coffee cherries normally contain two beans. About 5% (the peaberries) have only one, and the bean becomes rounder as a result; double beans are flattened on the facing sides.
Robusta can be grown anywhere with a tropical climate. C. arabica is more picky: it is a tropical mountain plant, growing above 500-1000 meters, which demands cooler temperatures of 15-25C year round, with cool nights. A rainy season is needed in the growing and flowering season: 150-200mm per month is good. But the fruiting requires a dry season lasting three months. Frost is devastating to either plant.
The map below depicts the ‘bean belt’, showing where robusta and arabica (or both) are grown. The locations where C. arabica is grown coincide with regions of volcanic activity. Non-volcanic regions mainly produce robusta. Arabica is the phoenix of the floral kingdom: it thrives on volcanic soils.
As a forest plant, C. arabica likes to have shade and shelter. Banana plants are excellent for this: their large leaves provide shade (they also make good fertilizer), and the farmer can sell the bananas to supplement the income from the coffee. In Uganda, government advice is: take care of your bananas, and your bananas will take care of your coffee. However, large plantations often grow coffee in direct sunshine to maximise yield.
C. arabica is a small tree, but for ease of harvesting is normally kept as a bush. A new plant will take 3-4 years before it first develops small white flowers. The fruits, called coffee cherries, take up to 8 months to ripen. Eventually, they change colour from green to dark red and the harvest begins. Maddingly, each cherrie ripens at its own rate, necessitating checking the tree every 8-10 days with labour-intensive manual harvesting. The plants provide the highest yield when around 15 years old. The productive life is 25-40 years.
Romancing the bean
The bean is within the fruit. The flesh of the fruit can be removed by letting the fruit dry out in the sun (dry processing) or making the fruit rot in lots of water (wet processing): the latter is used mainly where the local climate lacks a dry season suitable for sun-drying. One type of wet processing even lets the fruit be eaten by animals and collects the beans from the fertilizer coming out at the other end – a coffee with curiosity value but do wash the beans well! After wet processing, the remaining beans still need to be dried in the sun for a couple of weeks.
Finally, the papery skin of the bean is removed, leaving the green coffee bean.
The beans are shipped to the coffee company and roasted. The roasting dries the bean further, breaks the shell and releases aromatic compounds from the kernel. Each roast has its own temperature and duration. A strong (dark) roast, at high temperature, will suppress the original taste of the bean. Arabica beans, with a more complex aroma, are normally lighter roasted. Robusta beans tend to benefit from a darker roast. However, many darker roasts do use arabica beans to good effect. Starbucks is particularly known for its dark roasts. Too light a roast can leave a sour taste.
Immediately after roasting, while the beans are still warm, flavoured oils can be added. Some afficionados will consider this ‘bad taste’.
After roasting the beans are finely ground, either in the factory or at home prior to brewing. Ground coffee begins to lose its taste quickly and cannot be kept for too long: for shipping it is vacuum-packed.
Brew and chemistry
The roasted coffee beans are edible, in moderation. More than 10-20 beans puts you at risk of caffeine poisoning, and be aware that coffee beans also contain cholesterol.
Healthier is to extract the flavour from the beans into a drink. The principle is easy: bring hot water into contact with the ground-up bean and serve the liquid. Basically, there are three ways to achieve this. One is to pour the hot water directly on the coffee grounds, either in the cup (drink with care) or in a cafetiere. Second, force steam at high pressure through the coffee grounds, producing less liquid but very strong coffee: espresso (the name refers to the high pressure). Third, percolate hot water through the coffee using a (paper) filter: filtered coffee. Each their favourite! Many variations are possible. Milk or cream and sugar can be added to taste. Dilute an espresso with hot water and you get an americano, large, with an unsubtle taste, the Donald Trump of the coffees. The creamy layer on top of the liquid retains some of the aromas and the trick of making coffee is to keep this intact.
The taste of the coffee depends on the quality of the bean. For the strongest coffees robusta is a common choice, but even for espressos the bean makes a lot of difference. Coffee filters can remove some of the aromas. On the other hand, people who need to control their cholesterol may want to stick to filtered coffees as the paper also removes some cholesterol-inducing compounds.
The best known compound of coffee is caffeine. In solid form it is a white powder, odorless but with a bitter taste. It occurs in some other plants. The role for the plant is as a natural pesticide, but for our use it acts as the world’s most popular stimulant. It increases alertness, affects the heart rhythm, delays the onset of sleep and reduces the total sleep time (but not the REM sleep). An overdose can lead to tremors, dizzyness and headaches – as well as death. Withdrawal symptoms (not applicable if the subject has died)
include severe headaches which can last a few days. Cheers!
Over 800 aromatic components are known in coffee. Most of the taste comes from about 20 of these, including vanillin and methoxyphenol. Caffeine itself has a bitter taste, which is very notable in robustas, and in strong coffees (especially Italian espressos). Instant coffees (made by freeze-drying) are also bitter. Several other compounds of coffee, such as quinic acid and trigonella, contribute to the bitterness. (Excessive quinic acid is the main cause of the bad taste when coffee is left on the heating element for too long.) The taste of coffee comes not only from the liquid itself, but also from the aromas which enter the nose, either directly or using the back route from the back of the mouth into the nose. Arabica is more aromatic; robusta coffee less so, leaving the bitter taste to dominate. The most complex taste comes from acidic components, such as malic acid and formic acid; these are especially strong in coffees grown on mineral-rich volcanic soils.
Coffea is a hungry plant which needs fertile soil. One 60 kg bag of coffee beans contains 1 kg of nitrogen, 60 g of phosphorous, 9 g of potassium, 16 g of calcium, 90 g of magnesium, 7 g of sulfur, 1 g of boron, 0.8 g of copper, 3.5 g of iron, 1 g of manganese, 0.002 g of molybdenum, and 0.7 g of zinc (www.coffeeresearch.org). All this has to come from somewhere! In rich soil, one coffee bush may produce 6 kilograms of beans per year (1200 cups of coffee), rich in aromas. A poor soil will yield very much less, and give a coffee which lacks taste. Coffee planted in poor soil is also more susceptible to disease, and requires pesticides – a bit ironic since the caffeine is itself a pesticide. The importance of soil can be seen by comparing Java to Borneo: they have the same climate but Borneo is geologically old and lacks the rich volcanic soils of Java. Coffee is a major crop in Java whilst Borneo has little agriculture – and no coffee.
In tropical regions, the heavy rains quickly impoverish the soil. This will not do for coffee. The soil needs to be rejuvenated, either by flooding (alluvation), glacial sediments, or volcanic ash. Glaciation would be surprising (putting it mildly) for the tropical climate which coffee needs. Flooding is a low-land process, and is important to robusta but less so for the mountain plant C. arabica – which also tends to die off in water-logged soils. This leaves volcanic ash as the main natural fertilizer. Soils derived from volcanic ash deposits are called andisols. Andisoils are normally light, easily tilled, and hold a lot of water: all excellent for coffee.
Volcanoes provide some further side benefits. They increase the elevation, good for C. arabica which is a mountain plant. The cone-like, isolated shapes attract rain, so that the slope (at least on one side) tends to be wetter than the surrounding land. Finally, C. arabica hates wet feet: volcanic soil does not become water logged (unlike clay), and furthermore, the slope of the volcanoes improves the run-off and therefore the drainage. The optimum slope is around 15 degrees.
The combination of altitude, drainage and slope, richness of soil and a tropical climate is volcanic dynamite. Coffee can be grown elsewhere, but the best coffee is grown on volcanic soils. Ashes to coffee grounds. But within reason: too much ash can badly damage or kill coffee plants. Coffee lives in a constant conflict between the need for volcanic eruptions and an inability to survive them.
Location, location, location
Ethiopia remains the heart of coffee: the origin of Coffea arabica, the location with most genetic diversity (perhaps as many as 4000 distinct varieties) – and where it is valued most by the local population. Half the coffee grown in Ethiopia is consumed locally; still, coffee accounts for 40% of all of Ethiopia’s export earnings (before 2000 it was as high as 70% but other export products have since grown in importance). The beans are roasted at home using a flat iron pan, ground, and boiled in water for 15 minutes. An intricate ceremony can be attached to drinking coffee, including burning of incense.
Sidamo (the southernmost province of Ethiopia) is particularly famous for the best-known export, Yirgacheffe coffee. Sidamo coffee has a complex, citrus-like but mild taste. Lekempti, from the west, is sweeter and lacks the citrus acidity. Harrar coffee, grown in the east of Ethiopia, is often used in espresso blends. It can have a blueberry-like aroma, and is used to add taste to the espresso mix. Unusually, Harrar coffee is grown under desert conditions.
The Ethiopian forests where coffee grows wild are rapidly disappearing under the pressure of a burgeoning population. This puts in danger the genetic diversity of the wild plants, an essential resource to combat future coffee diseases. A UNESCO Biosphere Reserve is helping to protect some of the remaining mountain rain forest.
Harrar coffee is grown close to Ethiopia’s most active volcanoes, which are found in the Afar depression. The other coffee-growing areas, towards Kenya, are closer to the rift valley and aided by the volcanoes found there. Of the nearly 60 volcanoes identified in the rift valley, at least three have been active in the past 10,000 years. Corbetti erupted around 400 BC, and Aluto perhaps 2000 BC (recently the latter has shown inflation). The ash from Ethiopia’s rift volcanoes fertilize regions well away from their immediate vicinity. Ethiopian coffee is a living gem, evidence of Africa’s volcanic heritage.
If Ethiopia is the heart of coffee, Yemen is the mind. The volcanic soil of the Yemeni mountains has been used to grow coffee for over 500 years. There are many local arabica varieties, closely related to those grown in Ethiopia, but each one is subtly different. Coffee is grown mainly in the mountains in the west of the country, surrounding the capital Sana’a. The mountains here have a number of eruptive volcanoes. The most recent eruption was in 1937, in a 3500-m high volcanic field called Harras of Dhamar. The coffee cherries grow during the summer rains, and dry in the autumn when the desert reclaims the mountains.
Ethiopia and Yemen carry almost all of the genetic variability of Coffea arabica. Elsewhere, coffee plants are genetically rather uniform.
Tanzania and Kilimanjaro
All Tanzania’s volcanoes are surrounded by arabica plantations. Famous Mount Kilimanjaro is the centre of the coffee growing region of Moshe, which also contains Mount Meru and Ol Doinyo Lengai. Mount Meru last erupted in 1910, and Ol Doinyo Lengai is currently active: this is the volcano which fertilises the grasslands that make the wildebeest migration possible. If the rite-of-passage climb of Kilimanjaro proved too much, a local coffee tour could still give the expedition a taste of success!
The Moshi region has fewer than 200,000 people, and is poor, with little infrastructure and poor roads. As you may expect from a coffee-growing region, there can be a lot of rain. Traditionally, the local Chagga people grow the coffee bushes in shade, underneath larger trees. Starbucks is reported to be a major buyer of their coffee. However, most of the coffee is grown on plantations, which are replacing the local coffee varieties by ones that tolerate sun and have better resistance to fungi.
A second volcanic region in Tanzania is in the southern highlands, north of Lake Malawi, with Mount Rungwe the best-known peak. It probably erupted a few hundred years ago. Away from volcanoes, arabica is also grown in the Matengo highlands, east of Lake Malawi, and next to Lake Tanganyika in the Great Rift Valley region. The main robusta growing area is to the west of Lake Victoria.
Guatemala has the reputation of producing some of the best coffees in the world, and some of the most expensive. What to expect from a country as littered in coffee plantations as it is in volcanoes?
Coffee is grown above an altitude of 500 meters, but needs protection from frost at higher levels. Almost all coffee is shade grown: the trees create vibrant eco-systems where the natural insects and birds (and the caffeine content of the plants themselves) reduce the need for pesticides.
The central coffee authority (Anacafe) recognizes eight different Guatemalan coffee regions: Acatenango, Antigua, Atitlan, Coban, Fraijanes, Huehue (producing the world’s most expensive coffee), New Oriente and San Marcos. Five regions are known as volcanic and those are Acatenango, Antigua, Atitlan, Fraijanes and San Marcos. This leaves Coban, Huehue and New Oriente as non-primary-volcanic regions.
Coffees from the volcanic regions are normally slightly more mineralized in flavour compared to the non-volcanic. But this is not the full story. All parts of Guatemala are now and then dusted with volcanic ash, and not a single region has avoided being covered in deep blankets from massive eruptions from Amatitlan and Atitlan. So, in a way the non-volcanic regions should be known as semi-volcanic regions.
This leaves foremost Huehue with a beautifully balanced coffee that has taken center-stage as the best coffee known to humankind. In Europe or the US a kilogram of El Injerto Huehue coffee can cost as much as 1,000 USD. Rather than paying this, Carl (our Guatemalan coffee expert) recommends spending the money on an air ticket, to visit El Injertos cafe in Guatemala City in person. A cup of their fabled coffee will be produced for you by an expert for as little as 7 USD, and that cup will be, in comparison, even counting a reasonable cost for the flight, the cheapest cup of coffee you ever had.
Take your cup and go out into the street. If you are lucky you will see Pacaya or Fuego happily puffing away the ash that gave your cup its taste.
Indonesian Java Moccha coffee used to be famous. The coffee seeds were brought here from Yemen, and production grew huge. But coffee rust wiped out many of the plantations. A large research project was started to improve on the Yemen varieties. C. canephora, known as C. robusta, was found to be disease resistant, and robusta coffee was born. But although it worked miracles for the disease resistance, it was less wonderful for the quality. Some arabica/robusta hybrids were developed, but again these did not come close to the best coffees. Coffee plantations in Indonesia also regularly suffer from too much ash from its overactive volcanoes.
In consequence, Indonesia is still a major coffee producer but now supplies mainly the less demanding markets. It is often used in instant coffee and in espresso mixes. Sumatra coffee is affected by a lack of iron in the soil. Some arabica is still grown, and the best coffee comes the highlands around Lake Toba. The Tambora region also grows coffee. Archeology has shown that coffee growing here began before the 1815 eruption.
Mauna Loa: Kona coffee
Hawaiian Kona coffee is grown on the western slopes of Mauna Loa, between 100 and 800 meters above sea level. This is a lower altitude than usual for coffee, aided by the tempering effect of the coolish ocean. The Mauna Loa area is known as the Kona Coffee Belt; it is about 50 kilometer long but only two kilometers wide. Only coffee grown in this specific area is allowed to be referred to as Kona coffee. Kona coffee was originally derived from Guatemalan varieties.
Rainfall in the Kona belt amounts to about 1500 mm per year. Most falls in the afternoons. There were very few pests found in this region, but regrettably the coffee-berry-borer beetle has recently arrived on Hawaii.
Kona coffee is a smooth, light, excellent coffee, but known especially for its price. If you can afford it, go for the pure Kona coffee. Blends are a bit cheaper but may contain as little as 10% Kona beans. Much better to spend the same amount on a bit less, and enjoy the real thing. Try the Coffee Shack, along highway 11 on the Island of Hawaii in the Kona belt (pick a quiet time and go for coffee rather than lunch). It looks like a shack from the front but the views from the terrace are breath taking. Coffee viewing at its best.
Vietnamese coffee is best avoided.
Brazil produces 30% of the world’s coffee. 75% of its production is arabica and 25% robusta. Brazil bourbon is well known. Coffee is mainly grown in the south-eastern states, especially around Sao Paulo. Occasionally, severe frosts devastate plantations and necessitate large-scale replanting. Because almost a third of all coffee comes from Brazil, this can cause major price fluctuations.
In Brazil, quantity has at times ruled over quality and the product is often sold as blends, mixing the good with the bad. And dare I mention a lack of volcanoes?
Volcano coffee: a final word
Coffea arabica is a fragile flower, the diva of agriculture, which will only perform if provided with a stable climate, cool tropical temperatures, rich, well-drained soil; the kind of plant for which paradise was invented. Volcanoes give it everything it wants, minerals, drainage, microclimate. Here is the paradoxical plant that wilts in heat but lives by fire. Other coffees are less picky, grow anywhere, have higher yields, but like non-volcanic mountains, lack excitement. Spoiled arabica remains the top performer. And in return, this picky plant provides more development aid than any western government ever has, provides a living for poverty-afflicted regions, and pays for any damage ever done by any volcano. Not bad for a bean.