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Theobroma cacao as a replacement species for Caffea arabica in Central American farmlands of under 1000 meters in elevation

Coffee farmers of the Central American countries of Nicaragua, Honduras and El Salvador and to a lesser degree Colombia are increasingly faced with a difficult decision looming in the horizon with regards to the economic sustainability of their farming practices in the near future. The vegetal and atmospheric realities caused by climate change disturbing coffee farms in areas under 1000 meters of elevation on the one hand, and the economic pressures produced as a result of an increasing demand for premium Arabica coffee produced in high altitudes on the other – 1000 to 2000+ meters – are increasingly threatening the sustainable future of mono-cropping in coffee farms of Central America. While farmers of higher altitudes are increasingly incentivized to perfect their production of specialty coffee, owners of small low altitude traditional coffee farms that average around just over 2 hectares of land under production are facing serious climatic issues in the near future with the respect to rising global temperatures. In the ensuing discussion, the argument will analyses the potential of cacao plant to either replace Caffea arabica or serve as a diversification crop during a transition period from coffee to cacao, as many of the productive lands of the aforementioned low lying areas are becoming increasingly unsuitable for cultivation of coffee. On the one hand, the argument will focus on vegetal qualities of Theobroma cacao as a well-positioned replacement for Caffea Arabica. On the other, the research will discuss the logistical suitability of this replacement as a result of the similarity of post-harvest processing, and the relatively analogous supply chains shared between green coffee and raw cacao beans.

A recent report by the International Centre for Tropical Agriculture indicates that Costa Rica, El Salvador, and Nicaragua are in the fore front of the full impact of climate change with regards to suitability of land under cultivation of coffee. Climate models indicate that by 2050, the majority of the low lying areas – under 1000 meters of elevation – of Mesoamerica will, in all likelihood, experience an increase of 2 to 2.5 degrees in Celsius in mean annual temperature. Moreover, the majority of the region will experience between 5 to 10 percent differential in annual precipitation. (CIAT)

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Table from CIAT

Given that Caffea arabica is incredibly sensitive to climatic stress, the changing mean annual temperatures will cause a tremendous challenge for coffee farmers in the region. Higher ambient temperatures speed up the ripening process of coffee cherries and therefore result in poorer cup quality. In a region where coffee production is the predominant source of agricultural GDP especially among the small farming families, the degrading quality will directly impact household income as the resultant green bean will certainly fall outside of the 80 percentile mark determined for high premium yielding specialty coffee. (CIAT)

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Global map of production of coffee based on species and its consumption – Produced by Author

Moreover, given that coffee is a native plant of the understory layer of southwestern highland forests of Ethiopia, it has biologically adapted to steady and slow vegetal growth. The primary production of coffee in Latin America however takes place in full sun where the coffee plant is in effect growing and producing cherries at much higher rate than it is biologically accustomed to. This differential in growth and production cause a tremendous increase in susceptibility to diseases such as leaf rust disease. Increasing mean temperatures and increasing photosynthetic production as yielded by climate change will, in all likelihood increase the potential in Caffea arabica’s susceptibility to leaf rust disease.

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Diagram explaining coffee plantation according to its natural habitat on the top, versus commercial modern plantations in the bottom

Given the narrow climatic conditions that the coffee farms operate within, and given the social and economic structures that comprise the coffee agriculture in this region of the world as one of the few place where rustic or semi-rustic polyculture agroforestry systems persists within a closely knit network of small farm producers, a number of global organizations such as CIAT have invested interest to conduct research as a potential model for combating climate change induced stress in agriculture in other regions of the world. As a result, in all likelihood, there will be an increasing amount of research, initiatives, and funding available for programs that support polyculture or replacement of coffee with other suitable crops. (Coffeelands, Responding to) However, it is important to take into account that many farmers in this region of the Mesoamerica have been farming coffee on lands averaging around 2 hectares using traditional wet mill processing and patio drying for more than 150 years in successive generations. A systematic diversification or complete change in agricultural crop of choice in this region of the world may take more than just research, as local, governmental and international support with regards to implementation and education will certainly be necessary in order to achieve a successful transition. In Nicaragua for instance, majority of farmers do not call themselves cacao farmers, although many small farmers do cultivate and harvest cacao as third or fourth crop. One of the main issues with respect to the potential for cacao as the primary crop in this region is the incorrect attitude that cacao is a low maintenance crop. Many coffee farmers have a small number of Theobroma cacao plants that they harvest as a third crop with very little adequate post-harvest handling. They typically sell the raw and often poorly fermented cacao bean in local markets. As a result, the poor quality of cacao produced and sold using these practices undermines the full capacity of the species as a major source of agricultural income for these small farmers. (Cacao Bisiesto, Cacao in Nicaragua)

The reality of climate change with regards to the production of coffee is not only limited to disease susceptibility and cup quality in that the rising temperatures could easily shift the altitudinal range of the crop upwards over time. Using a simple method of plant classification according to the age old system devised by Alexander Von Humboldt, it is easily recognizable that all species migrate with regards to their range across the global latitudes, as well as across a vertical range in accordance to their altitudinal habitat. These habitats are not fixed and therefore as the global temperatures change over time, the territorial range of species move accordingly. As a result, Von Humboldt first proposed that plant species should not be classified based on nativity to specific regions, but rather in accordance to their altitudinal tolerances. This method of classification is of particular importance to tropical agriculture, and it should be noted that Von Humboldt prioritized altitudinal ranges over latitudinal ones in that latitudinal temperature variations are much less noticeable than changes across elevation in the tropical Central America as a result of extreme topographies and climatic systems created by the Andes.

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Drawing by Alexander Von Humboldt explaining the altitudinal range of different dominant species

For instance, given that every 100 meters of change in elevation will result in an approximately 0.5 degrees of Celsius change in temperature, it is easily deducible that with the given predictions of 2 to 2.5 degrees change by 2050, the production of high quality coffee could certainly move up the mountains by 400 to 500 meters in elevation. (Coffeelands, Knocking on) More importantly, as the production range of lower quality coffee will adjust accordingly, the resultant 400 meters in elevation change will encompass much larger territory across lower altitude foothills that have less altitudinal differential across the terrain. As a result, coffee farmers are faced with three primary choices. They may diversify and eventually completely change to a different polyculture of agricultural regime. Alternatively, many farmers could decide to rely heavily on a losing battle of subsidized disease resistant research that supplies specific Arabica strains resistant to leaf rust. Thirdly, the emerging generation may choose to leave farming with migration from rural areas to heavily populated cities.  While option two is a temporary solution at best, option three is not only economically inconceivable, but from an ecological perspective the deserted agricultural territories will experience massive soil erosion and potential landslides as a result of the susceptibility of the volcanic soil in these areas that is ironically very fertile but extremely fragile in the face of erosion. Luckily, Theobroma cacao is an incredibly well suited plant for the circumstances of these conditions. Cacao thrives in warm temperatures, deep soils with abundant organic matter. The species love the evenly distributed rainfall pattern of low lying tropical lands with a minimum of 1200 mm of precipitation per annum. (Coffeelands, responding to) More importantly, given that cacao is a native of riparian zones of the tropics, it has evolved to develop an unusually long tap root for a tropical plant. As a result, Cacao plant is extremely well positioned to combat soil erosion in these areas of the Central America. Moreover, Cacao, much like coffee is produced primarily by farmers that share very similar socio-economic profile to that of coffee farmers. 90 percent of cacao is produced by small family owned farms ranging between 1-5 hectares in size. (Coffeelands, Responding to) Above all, perhaps the most important statistic is Cacao plant’s altitudinal range with an optimal elevation band of 100 to 600 meters above the sea level, making cacao a perfect diversification or even replacement plant for low altitude coffee lands that will eventually fall outside of Caffea arabica’s production range.

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Diagram explaining suitable soil make up for cacao plant’s deep tap root morphology

A secondary but perhaps more crucial factor from a socio-economic perspective are the similarities that coffee and cacao share with regards to post-harvest processing and the market structures with regards to production and supply chains. The post-harvest processing for coffee in Central America is predominantly based on wet mill processing and fermentation, with an extremely small group of farmers, mostly in the south and in Brazil relying on dry fermentation. The main driver in this split is the marketability to consumers in the Northern Hemisphere where most of coffee enthusiasts and everyday drinkers are used to the clear, crisp and to some degree bright profile of Latin American high altitude coffee. Dry fermented coffee results in a much fruitier and a much earthier coffee in that coffee cherries are not de-pulped before fermentation. This difference and the need for a wet mill is perhaps the only primary difference in the post-harvest processing of coffee and that of raw cacao beans. Both crops need extensive flat spaces for drying and fermentation with the possibility of utilizing movable trays for both industries. Although the knowledge required to perfect the fermentation process of each crop is fundamentally different, with adequate support and education, small coffee farmers of under 1000 meters of elevation could very easily diversify or completely switch to cacao production.

As previously mentioned coffee is predominantly produced in this region of the world within family owned farms averaging approximately 2 hectares in size. Cacao is also produced within farms of similar make up ranging from 1 to 5 hectares in size. Both crops are produced by an aging demographics with the average coffee farmer and the average cacao farmer both at around 55 years of age, with an increasing number of individual farmers whose children are more and more likely to refrain from continuing the familial trade, in part due to the diminishing profits of the bulk production of both crops. As a result, many metropolitan areas in Central America, West Africa, and East Asia have experienced a massive migration boom of predominantly young workforce encouraged by their previous generation to abandon the agricultural lifestyle. Another important similarity between the two crops is the emergence of a relatively new consumer base that is willing to pay a premium for higher quality raw products. In coffee, the so-called third wave which coffee enthusiast have described as post-Starbucks movement, has mobilized a robust direct trade movement in number of Latin American countries. For instance, Pedro Miguel Echavarria, the founder of Pergamino Café in Medellin is at the fore front of establishing a sophisticated coffee culture in the bustling and growing metropolis of his home town. However, the primary constituent of his growing business consists of sourcing specialty coffee directly from Colombian farms to American coffee roasters.

Cafe Pergamino in Medellin, Colombia

Although direct trade has its own shortcomings in both industries, the so-called exclusive quality that is promised through direct sourcing has resulted in emergence of local cooperatives that are more conscious of quality and DO (Designation of Origin). delos Andes Cooperativa for instance, situated near the city of Andes in Antioquia, has recently equipped itself with highly technological sorting machines that have the capacity to de-shell and process specific green coffee batches separate from one another, in order to preserve the integrity of DO. Although cacao seems to be slightly behind coffee with respect to DO, and coffee itself is tremendously behind wine with regards to DO as a marketing tool, there seems to be a growing evidence that there will be more place-specific sourcing of both products in the future as the consumer base in the Northern Hemisphere pay higher premiums for quality raw products. (Coffeelands, A Napa Valley) The issue that has particular importance with regards to this argument is the commonality of the networks of social, marketing, and trade infrastructures that regulate the supply chain of both crops. Due to this observation, a diversification strategy or complete replacement of coffee framing with cacao in areas that will eventually fall outside the altitudinal range of Caffea arabica could be a potential success.

delos Andes Cooperativa near Andes, Antioquia, Colombia

The argument put forward here makes a compelling argument for on the one hand the need to diversify and ultimately replace coffee as a monocrop in low lying farmlands of Central America. On the other, the analysis has identified Theobroma cacao as an incredibly suitable species for this replacement, in that cacao plant’s biological capacities that are matched for this vulnerable territory, coupled with the potential as a result of the overlapping trade infrastructures and post-harvest techniques with that of coffee industry, makes cacao a potential successor to coffee in farmlands of lower than 1000 meters in elevation. Nevertheless, as identified by this research analysis, there are many challenges at governmental as well as farm level that would require extensive support and education through industry imitated programs. In short, the effort takes more than just sprinkling cacao plants in coffee farms.

 

Sources:

“A Napa Valley Vineyard – a Glimpse into the Future of Coffee Farming?” Coffeelands. Web. 04 May 2016.
“Cacao in Nicaragua.” Cacao Bisiesto. Web. 04 May 2016.
“Knocking on Coffee’s Door: Cocoa’s Case as a Coffee Farm Alternative.” Coffeelands. Web. 04 May 2016.
“Responding to the Climate Crisis through Crop Diversification.” Coffeelands. Web. 04 May 2016.
Thelen, Jeff. “Pergamino Café: Forging a Coffee Culture in Medellín.” The Huffington Post. TheHuffingtonPost.com. Web. 04 May 2016.
“Mesoamerican Coffee: Building a Climate Change Adaptation …” CIAT. Web. 4 May 2016.

“Fine Flavor Cacao – FFC”

While the market for “specialty” coffee has been growing steadily over the recent years, fine cacao market has lost a dramatic share to bulk cacao since early 1900’s. The same comparison with wine industry is even more astonishing. Wine industry since the middle ages and early Renaissance, has grown into an exclusively “specialty” sector. That is to say wine is almost exclusively bottled under different premium yielding “Designation of Origin” privileges that are regulated through different governmental and cooperative bodies. What does “fine” cacao mean? The answer to this question might unlock immense potentials for the cacao market. The ensuing article will draw comparison between the three industries, arguing for the necessity to better define the term “fine” cacao. More specifically, the study will briefly analyze the development of knowledge pertinent to “fine flavor”, “specialty”, and “Designation of Origin” in relation to  cacao, coffee, and wine respectively, as a method to better understand the potential contributing factors in the classification of cacao and its flavors.

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Valrhona using wine marketing strategies as they reference their company headquarters near Burgundy

 

The term “fine” or “flavor” cacao – FFC – as described by the International Cocoa Organization, refers to cacao beans produced primarily from Criollo or Trinitario varieties of the plant species Theobroma cacao. (ICCO) This distinction however, is not entirely well-defined, given that there are numerous exceptions to this classification. For instance, Nacional trees in Ecuador and Peru which are a Forastero variety are considered FFC producing sub-varieties. Conversely, Trinitario trees from Cameroon that produce a highly sought after red cocoa power, are classified as bulk cacao.(ICCO) One of the primary issues with the FFC classification is the extreme reliance on flavor and post-harvest testing such as organoleptic quality test as the designating factor, without classification of the underlying conditions that impact the flavor of cacao beans. In comparison, wine industry defines D.O. – Designation of Origin – in relation to cultivar traits of Vitis vinifera species, characteristics of “place” as a result of topographic, atmospheric, and edaphic conditions, and finally post-harvest handling and processing. All of these traits may be combined into what is commonly referred to as Terroir. In other words, the wine industry uses a much more complex set of well-studied characteristics in order to market a range of combinations with regard to flavor, all of which will result in a certain premium.

 

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Terroir has become a marketing tool for the wine industry in order to create a much more complex system of sourcing than that of coffee and cacao.

 

Coffee industry uses the term “specialty” in a slightly less complex system, and far less regulated. For the most part, “specialty” coffee is the exclusive product of Arabica trees with no specialty classification in the lower quality Robusta trees. Specialty is always a single origin coffee of at least 85 percentile quality that traces back to a specific farm and it is typically grown at an altitude between 2000 to 4000 feet and above. Additionally, there are more well-defined classifications within the specialty category that further categorize fine flavor according to altitude. Coffee that is grown at a higher altitude grows slower, produces harder bean, and results in a cup with much finer flavor profile. As a result, the SCAA, Specialty Coffee Association of America classifies specialty coffee in a spectrum of hardness with Strictly Hard Bean designating the best quality for Arabica trees growing at 3900 feet and above. According to SCAA, specialty coffee currently accounts for only 3 percent of global trade. (SCAA)

 

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Altitude map describing the relationship between flavor and elevation – source: George Howell 

 

Genetic stability is another factor of importance in relation to all three industries. For wine, the characteristics shared by vines tend to follow an underlying and well understood genetic traits within the Vitis vinifera species. (Nesto, 4) Furthermore, given that vine is propagated through cloning, vine varieties tend to have a highly persistent genetic makeup. Caffea arabica also has a highly stable genetic makeup because it is a self-pollinating species. Cacao tree however, is a highly diverse species with an incredibly varied genetic makeup. Forastero in particular is highly diverse because it is not a self-pollinating plant. Although Criollo is a self-pollinating tree, many Criollo varieties have also lost their capacity to self-pollinate as a result of hybridization with Forastero varieties. (Nesto, 4) Many of these hybridizations are undertaken in order to produce varieties that share the FFC qualities derived from Criollo and disease resistance and high yielding traits from Forastero. The primary downside of these practices is the lack of consistency in the flavor profile of cacao beans. Although no two bottles of wine are exactly the same, bottles from the same year and the same vineyard that have utilized the same grape are typically indiscernible. In cacao farms it is not unusual to have plants of the same variety producing pods with dramatically different colors, and beans that result in different taste profiles. One of the potential solutions as suggested by a study partially sponsored by CIAT, is to look for the right heritage Criollo or Trinitario that is suitable for the particular geographic region in mind, and incorporate practices from wine industry in order to increase yield and reduce diseases as oppose to hybridization with Forastero varieties. (Daniels, 7)

 

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Genetic clusters for Theobroma cacao based on underlying common traits – Source: Motamayor

 

Furthermore, a comprehensive and more stable classification of Cacao tree based on underlying genetic traits is the first step towards a stable FFC industry. In 2008, Motamayor and colleagues proposed the classification of the cacao plant into ten genetic clusters as Marañon, Curaray, Criollo, Iquitos, Nanay, Contamana, Amelonado, Purús, Nacional, and Guiana. (Motamayor) This categorization may be a first step towards stabilization of a varietal range from the cacao plant.

 

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Ten Genetic Clusters as proposed by Motamayor – Source: Motamayor

 

 The comparative analysis between cacao and coffee is potentially positive in that the two industries share an overwhelming number of similarities, and they can both benefit from case studies in relation to wine industry which has a more complex system of sourcing. As it is shown in the global map, both crops are cultivated in the tropical belt, with export to countries in the northern hemisphere as the primary consumers. Furthermore, in the past decade, there has been a resurgence of interest in single origin and sourcing within both commodities. In cacao for instance, according to Hershey senior VP Tom Hernquist, the demand for dark chocolate rose from 8 percent in 2004 to 24 percent of the market in 2006.(Daniels, 6) Although this is an estimation by Mr. Hernquist, it highlights the potential role FFC can play in the future of cacao industry. Although the growth of FFC is contingent to the rethinking of the supply chain, and the business model associated with the industry at large, genetic stabilization and better understanding of the underlying genetic and environmental factors that produce flavor are the first crucial steps in the spread of FFC in the global market.

Sources:

Avelino, Jacques, Bernardo Barboza, Juan Carlos Araya, Carlos Fonseca, Fabrice Davrieux, Bernard Guyot, and Christian Cilas. “Effects of Slope Exposure, Altitude and Yield on Coffee Quality in Two Altitudeterroirs of Costa Rica, Orosi and Santa María De Dota.” Journal of the Science of Food and Agriculture J. Sci. Food Agric. 85.11 (2005): 1869-876. Web.

Daniels, Stephanie, Peter Läderach, and Melissa Paschall. “Reaching High-Value Markets: fine flavor cocoa in Ghana”. Sustainable Food Lab (2012). Web.

“ICCO – International Cocoa Organization.” Fine or Flavour Cocoa. Web. 11 Mar. 2016.

Motamayor, Juan C., Philippe Lachenaud, Jay Wallace Da Silva E Mota, Rey Loor, David N. Kuhn, J. Steven Brown, and Raymond J. Schnell. “Geographic and Genetic Population Differentiation of the Amazonian Chocolate Tree (Theobroma Cacao L).” PLoS ONE 3.10 (2008). Web.
Mussatto, Solange I., Ercília M. S. Machado, Silvia Martins, and José A. Teixeira. “Production, Composition, and Application of Coffee and Its Industrial Residues.” Food Bioprocess Technol Food and Bioprocess Technology 4.5 (2011): 661-72. Web.
Nesto, Bill. “Discovering Terroir in the World of Chocolate.” Gastronomica 10.1 (2010): 131-35. Web.
“SCAA – Specialty Coffee Association of America.” Specialty Coffee Association of America. Web. 11 Mar. 2016.

Criollo: An Endangered Variety

Fine cacao production is estimated to account for less than 5 percent of the global market. Criollo variety, the ancestor to a number of contemporary cultivars accounting for the majority of this thin market, is believed to be domesticated by the Mayans during the Classic Period around 900 AD (Penn). While Criollo cultivars are relatively scarce in the contemporary cacao cultivation, they have accounted for the majority of cacao cultivation for most of its history.

 

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reproduction of the colored plate by M.S. Meriam (1705 Amsterdam), The first iconography of Criollos Cacao in America (Dutch Guiana)

Although a number of different factors ranging from the introduction of hybridized varieties across new territories to mass production of chocolate have all contributed to the current preference of Forastero over Criollo, the decline of Criollo is predominantly due to substandard yield and high susceptibility to diseases like witches broom, water-pod disease and brown pod rot. Of the numerous Criollo varieties, the so-called “purest” are in fact the most vulnerable to these diseases.

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Distribution of Cacao cultivars around the globe

One of the most sought after varieties, Porcelano, known for the white beans and it’s translucent white juvenile pods is infamously fragile, hard to cultivate, and susceptible to all three diseases. (Ciferri, 387) Porcelano is a non-botanical common name describing the white bean sub-variety of Criollo cultivars in Venezuela, south of Lake Maracaibo. (Presilla, 65) A variety similar  to this cultivar is also found in the Peruvian Nacional varieties with appearance similar to the Venezuelan Porcelano.  Although many of the specialty cacao cultivars have low disease resistance, the substantial premium they could account for in comparison with bulk cacao may be a source of increased income and quality of life in an industry where the average farmer makes approximately $2 per day depending on region and quality of production. (Penn state)

 

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Porcelano Criollo pod in one of the very few remaining Porcelano groves near Lake Maracaibo, Venezuela.

Genetic sequencing results published by Penn State on a number of Criollo varieties have shown that due to the intrinsic self-pollinating characteristics of Criollo as a dioecious plant – a plant that has both male and female organs – Criollo cultivars are uniquely homozygous; their genome contains duplicates of the same gene.(Penn State) This condition, although does not directly cause a disease, is well studied in humans and mammals where genetic conditions, such as lower resistance to disease and autoimmune disorders, may be caused by a pair of recessive alleles. Although this is not entirely studied in the cacao plant, given that the genome itself was sequenced just recently, it is likely that similar duplicate genes may result in lower disease resistance characteristics among Criollo cultivars in comparison to Forastero cultivars.

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Genetic sequencing of Theobroma cacao

Genetically modified disease resistant Criollo varieties may be the future of saving this seemingly endangered plant.(Penn State) However, that will further neutralize the gene pool as it will favor the propagation of a single “breed” over a range of available genetic diversity within Criollo varieties. A similar situation in coffee, specifically in the more fragile and lower yielding Caffea arabica, has led to the introduction of a single disease resistant variety that is threatening to neutralize the diversity of Arabica, most notably in the Colombian market. An alternative solution is to promote cross-breeding of varieties within the Criollo family in order to increase the diversity. In turn, specialty cacao, much like wine and specialty coffee can focus on designation of origin, not only in regard to plant variety, but more importantly in relation to terroir.

Quality and taste profile of cacao beans have as much to do with the specifics of a place as it does with the particularity of the plant variety. Cacao prefers shade, yearly temperature of around 21 to 32 degrees Celsius. It prefers high humidity that is consistent across the year with no droughts and monsoons. The preferred soil is relatively sandy, nutrient rich, slightly acidic and well-drained with substantial depth that allows for the growth of cacao’s tap root. Cacao has an unusually deep root system for a tropical plant, because it naturally grows in well-drained riparian-zones. All of the above characteristics mean that cacao is highly particular, but as the cacao industry has shown, Theobroma cacao can tolerate conditions different from those listed above. The varying conditions are likely to – as of in the case of coffee and wine – contribute to place-specific taste profiles that may be marketed under specific designation of origin, much like the concept of Appellation in the French wine industry.
The argument here is to suggest that specialty could be different from the Eurocentric notion of purity; purity as it was found in a seemingly static state in one moment in time and history. Perhaps the cacao plant could cross-breed across different varieties with more attention given to particulars of “place” as opposed to specificity of cultivars.

The Atlas of Economic Complexities interactive map 

 

Sources:

Ciferri, R., and F. Ciferri. “The Evolution of Cultivated Cacao.” Evolution 11.4 (1957). Web

Penn State. “Finest chocolate may get better: Cacao tree genome sequenced.” ScienceDaily, 28 December 2010. <www.sciencedaily.com/releases/2010/12/101226131600.htm>

Presilla, Maricel E.“The New Taste of Chocolate.”Berkeley: Ten Speed Press, 2009. 1-59. Print

Zhang, D. “Genetic Diversity and Structure of Managed and Semi-natural Populations of Cocoa (Theobroma Cacao) in the Huallaga and Ucayali Valleys of Peru.”Annals of Botany” 98.3 (2006): 647-55. Web.

 

Media Sources:

Merian, Maria Sibylla.Veranderingen der Surinaamsche Insecten. 1705. Engraved by Pieter Sluyter.https://upload.wikimedia.org/wikipedia/commons/d/df/Cacau_boom_Maria_Sibylla_Merian_1705_plate_XXVI.png

Xavier Algout,“The Genome of Theobroma Cacao.” Nature Genetics 43 (2011). http://www.nature.com/ng/journal/v43/n2/fig_tab/ng.736_F4.html