Monthly Archives: January 2009

Fuelling Up on Defective Coffee – the potential use of coffee oil in biodiesel production

By Carl Townsend and Annabel Townsend, Waste of the World project, University of Sheffield.


Based on findings by Oliveira et al (2007) and Kondamudi et al (2008 ), this paper aims to outline the socio-economic and environmental benefits of producing biofuels from the waste products of the coffee industry. On average, a fifth of all coffee grown in Latin America is defective, (Oliveira et al 2007) and cannot be sold on international markets where very high standards of quality are required. Using this defective coffee for fuel instead of for the production of low quality beverages would be beneficial to the small scale producers of coffee, as the defective beans may command a much higher price if sold to the biodiesel industry. Additionally, the main hindrance to biofuel production is the cost of crop production. By making use of the wasted by-product of the existing industry, both the economical, and environmental costs of biodiesel production could be reduced.

Nicaraguan Coffee

Nicaragua currently produces around 950000 bags of coffee for exportation per year, depending on the harvest, (Wallengren, 2008 ) and coffee exportation accounts for over a third of the country’s economy. However, due to extremely low prices for coffee on the world markets in the past two decades, there is increasing pressure for Nicaraguan, and other Latin American farmers to produce exceedingly high quality coffee. Green (unroasted) coffee beans are graded for quality using a scale devised by the Speciality Coffee Association of America (SCAA); any coffee achieving more than 60 points on this scale can be exported, and achieves the Fair Trade price of $1.26 per pound. Coffees with 80 points or more are classed as ‘Speciality’, and command a higher price – in Nicaragua this is around $1.80 per pound. World class coffees are graded at 90 points and above, and in 2006, Nicaragua produced one of the five highest graded coffees in the world, according to the independent Coffee Review journal. (Davids, 2006)

This emphasis on quality is not always reflected in coffee consumption, however. Less than 18% of the world coffee market comprises of Speciality coffees, the majority is low grade, low quality produce sold for much lower prices (Ponte 2002). In Nicaragua, the higher quality coffee is all exported, leaving the low grade beans for domestic consumption. The same is also true of other producing countries, such as Brazil and Colombia. (Oliveira et al 2007, Mance 2009). Selling coffee on national markets also severely restricts the prices these coffee crops can command, to the point where the price falls below the cost of production, leaving the coffee farmers in a very precarious position.

Coffee quality is affected by a number of factors, some of which can be controlled by the skills of the farmer and by the methods of processing. Other factors cannot be controlled, however, such as climate conditions and physical geography. According to a guide to coffee cupping (sampling and grading) produced by catadores (cuppers) at Santa Emilia Estate in Matagalpa, Nicaragua, “desde el campo, vienen la calidad’ (Santa Emilia, 2006) or ‘from the country, comes the quality.’ Growing high quality coffee requires a humid, temperate climate with night temperatures not falling below 20°C year round. It also requires high altitudes of at least 700m above sea level, relatively high rainfall during the growing season and a hot dry climate after harvest season in order to dry out and process the beans properly. Speciality coffees are also restricted to the coffea arabica variety, which has a better flavour but is much more susceptible to adverse climate conditions, disease and pests. In practical terms, this means that high quality coffees are very difficult to grow, particularly when international demands for organic produce mean that chemical fertilisers and pesticides cannot be used. Without the necessary climate and geography, it is impossible to produce high quality organic coffees. Further still, no coffee crop can ever be 100% high quality; there are always going to be defects, no matter how conscientious and skilled the farmer may be.

Within Nicaragua, the market for coffee, both soluble (instant) and freshly ground, is strong. Nicaraguans as a nation drink a great deal of the beverage – “like it is water” – (Arghiris and Leonardi 2008:57). However, due to economic conditions, the prices for domestic coffee are low. Farmers do not receive a good price for their crop on the domestic market, and similarly, consumers do not pay much for their jars of nationally produced instant coffee. The vast majority of Nicaraguans drink very low quality coffee, and often never taste the award winning produce grown locally.

Presently, there are efforts to amend this trend. Cecocafen, an organic and FairTrade certified coffee cooperative based in the Nicaraguan department of Matagalpa, have launched a brand of ground coffee called “Café El Sabor Nica” or Nicaraguan flavour coffee. It is a blend designed by expert cuppers at Cecocafen’s ‘Solcafe’ processing plant. sually, this coffee is roasted on the premises at Solcafe (most coffee is exported in its unroasted green state.) It is marketed as typifying the flavours of Nicaraguan coffee, akin to the concept of ‘terroir’ in the wine industry. Most interestingly, the slogan on the packaging claims the coffee is “export quality”. This brand is designed to encourage more Nicaraguans to drink, and appreciate their own coffee, and create a market less reliant on the fluctuations of international coffee prices.

This initiative is an exception rather than the norm in Nicaragua however. The issue still remains that over 20% of Nicaragua´s annual coffee crop cannot be exported due to its low quality. This coffee still requires the same resources, expenses, labour and time to grow, and so the farmers and producers still need a return on their investment in the crop somehow. It is often the case that this return does not come from selling the defective coffee on national markets.

The Need for Biofuels

Another major difficulty facing coffee farmers in Nicaragua is transportation costs. Over 60% of Nicaraguan coffee is grown on tiny farms with less than two hectares of coffee crop. These farms are necessarily located in remote areas often high up in the northern mountains. Most roads to these places are in very poor condition, and require heavy-duty 4WD vehicles to navigate them. (Aleman, 2008 ). Coffee quality is also severely affected by its freshness – ideally de-pulped and washed coffee beans should arrive at the dry processing mill within a few days of being harvested. (Katzeff 2001). Powerful vehicles and farm machinery, and especially the fuel to drive them is an expense few coffee farmers can afford, and at times, the quality of their coffee is reduced due to the beans over-fermenting, rotting or going stale as a result of delays in transportation. Improving the country’s road structure is of paramount importance, but so is allowing farmers more access to affordable, reliable transport.

In Brazil and other parts of Latin America, some crops are already being grown specifically for use in biofuels, such as soybean crops or sugar for ethanol fuels. Due to Nicaragua’s small size, mountain ranges, protected cloud rainforests and huge lake, the country is not ideally suited to conventional large scale crop and pasture cultivation, and so as yet, does not produce crops for biofuels. Neither does it import biodiesel for national use, and rising costs of oil and petrol across the world mean that running a vehicle is very expensive in Nicaragua.

However, this could be about to change. Scientists at the Universidade Federal de Minas Gerais in Brazil have found that it is possible to extract oil from coffee beans, which can then be processed into biodiesel using the same methods as extracting other vegetable oils. Coffee beans, both arabica and robusta varieties have quite a high oil content, which accounts for a good proportion of the distinctive aroma when roasted. Coffee oils can be seen as the ‘crema’ on the top of an espresso. With efficient processing, 10-15% of the coffee bean’s mass can be extracted as oil, which is equal to the yield from soybean and rapeseed crops. Extraction can be done either through cold-pressing the beans, or more efficiently, through solvent extraction. By-products of this process, solid matter and saponified substances like glycerine can still be composted and used as fertilizer, as is usually what happens to wasted and unusuable coffee beans. Alternatively, the glycerine could be burned to provide additional power and heating.

Coffee oil has been found to be very well suited to use in biodiesel, because the oil is naturally very high in antioxidants.(Oliveira et al 2005). This means that the resulting oil is very stable and does not decompose very quickly. Relatively low levels of saponified matter in the oil also means that it remains viscous and does not congeal easily. (Oliviera et al, 2007)

Most importantly, Oliveira et al (2005) discovered that defective beans actually yield more oil than healthy beans. Beans become defective or of low quality when they are over-ripe, sour or mouldy, or if they get wet after harvesting. All these factors allow the beans to mature for longer, increasing the oil content.

In most countries in Central America, coffea arabica is grown predominantly, with some farmers growing coffea canephora (robusta) as a form of failsafe against failure of the main, but less resilient arabica crop. Mazzafera et al (1998 ) show that arabica coffee beans contain 2-5% more oil than robusta, depending on the specific variety.

Practicalities of Biodiesel Production

As mentioned earlier, coffee beans can be cold-pressed to extract the oil, which is a simpler but less efficient method; or it can be extracted using solvents (please see Oliveira et al 2007 for more details of this process.) – which is more expensive and reliant on access to the appropriate chemicals, but produces a purer, higher quality oil.

A further issue with biodiesel production is the time taken, and monetary cost of the resources required to convert vegetable oils to biodiesel via a process known as transesterification. This involves processing the coffee oil with an alcohol (usually methanol) and a catalyst (typically sodium hydroxide or potassium hydroxide). During the reaction, the triglyceride molecule contained within the oil is broken down by the catalyst (forming the glycerine by-product) and replaced by the alcohol molecule provided by the methanol. Further processing is necessary to remove the soaps, glycerine and unreacted methanol; this results in a fuel with around the same viscosity as regular mineral diesel fuel, and which can be used as a direct, ‘drop-in’ replacement fuel for the diesel engine, including agricultural and power generating diesel engines. If, for example, biodiesel processing co-operative plants were to be set up in Nicaragua, it would provide coffee farmers with the opportunity to sell their low quality, waste beans to an alternative market for fuel instead of for national consumption. With world coffee prices continuing to drop and more emphasis placed on cheaper, environmentally friendly fuels, it is possible that the lower quality coffee could fetch a better price being sold as fuel rather than for beverages, if processing facilities became available, making more efficient use of a potentially wasted product.

In the current situation in Nicaragua however, biodiesel production facilities simply do not exist, and the majority of coffee farmers may find it very difficult to find the expertise to make this possible. But this does not necessarily mean that coffee oil cannot be used directly as a fuel. It is also possible to run most diesel vehicles, particularly farm machinery, using straight vegetable oil, or SVO, without converting it to biodiesel. Instead, the engine itself is modified with a two-tank system, starting up on regular diesel fuel (or biodiesel) until warm, and then switching to coffee oil, then shutting down on diesel fuel. Moreover, there are certain types of diesel engines, notably the indirect injection type (for example the XUD9 engine), fitted with a non-electronic Bosch injection pump, which have proven themselves capable of safely using vegetable oil directly as a fuel, with no modifications.

Finally, and perhaps importantly, there is a lack of knowledge. For a lot of people, the idea of running a diesel engine on vegetable oil is simply a wholly unknown concept. [CT1] In conversation with the Catador at Solcafe, Julio Obregon, about waste coffee beans, he was unaware that oil from these beans could be used. Vegetable oil was in fact one of the original fuels for Rudolph Diesel’s engines. He intended his engine to be run on a wide variety of different fuels (including coal dust!), and at the World Expo in Paris in 1900, he demonstrated his engine to the French, running it on peanut oil. It was a political decision, designed to show them a powerful, cheaper, highly efficient engine, not dependent on the inefficient and expensive steam engines that were around at the time, and most importantly, running on a fuel that the farmers in the French colonies could make themselves from some of their crops they set aside. However, the oil companies were quick to capitalize on this new engine, and began offering very cheap ‘mineral diesel fuel’, which was at the time a by-product of the petroleum refining process. The world soon forgot about vegetable oil as fuel, and diesel engine design became centered around the diesel fuel supplied by the oil companies. (Bdpedia 2006b)

Conclusions: the Benefits of Coffee Oil

Although coffee oil extraction and biodiesel production are reliant on expensive chemicals and equipment not readily accessible in Nicaragua[CT1] , the potential benefits of coffee oil use should not be ignored.

Low quality, waste coffee is an unavoidable part of coffee farming. When prices for this coffee are so low as to be below the cost of production, as is often the case particularly in Nicaragua’s domestic market, coffee farmers need a viable alternative for their crops. Setting aside a proportion of their crop for fuel could be very economically beneficial. Transport and processing costs of the low quality coffee would not be necessary, thus saving the farmer time and effort as well.

Using straight coffee oil in existing vehicles and farm machinery, as well as in electricity generators, is not only a more environmentally friendly alternative to fossil fuels, it would also be a considerably cheaper option for farmers struggling with rising fuel costs, while at the same time boosting their capacity for self-sufficiency, and decreasing their reliance on imported fuel. On a national scale, using low quality coffee for oil rather than for domestic consumption would in turn, force national coffee companies to improve the quality of their produce, as less low quality coffee would be available. This would then encourage Nicaraguans to drink better quality coffee in much the same way as Cecocafen’s El Sabor Nica brand intends to do.

On an international level, the benefits of biofuel use for the environment are well documented. (see, for example, 2006, or Bdpedia 2006a) Carbon emissions from biodiesel engines are a lot lower than from conventional engines, and use of straight vegetable oil reduces these emissions even further. At present, biofuel production is hampered by the cost of growing crops for fuel at the expense of growing them for food, particularly when staple food prices are rising all over the world. By using coffee oil, the biodiesel can be created from what is essentially a by-product of the existing coffee industry thus making better use of an otherwise wasted resource, and not impacting on the “food or fuel?” debates that have recently been taking place in the media and with environmental groups. ( 2006)

Finally, world coffee prices have decreased so dramatically in recent years, partially as a result of over-supply. (Ponte 2002). By using a proportion of the annual crops for fuel, this potentially restricts the amount of coffee available on the beverage markets, as well as improving the quality of it. Moreover, restricting the supply by diverting it to an alternative market could potentially boost the international prices of coffee, by adding scarcity value.

Coffee biofuel is still a long way from commercial production, and the feasibility of this will require more research in the future. However, the concept, method, resources and even the market for this already exist, and the benefits of coffee oil biodiesel certainly warrant considerable attention.


Arghiris, R., and Leonardi, R., 2008 Nicaragua Footprint:Bath

Bdpedia, 2006a Advantages of Biofuels and Biodiesel, The Biodiesel WWW Encyclopedia

Bdpedia, 2006b Biodiesel History, The Biodiesel WWW Encyclopedia

Davids, K., 2006 Nicaragua Cup Of Excellence,, 2006 The Advance of Biofuels – a boon for the climate?

Katzeff, P., 2001 The Coffee Cupper’s Manifesto, CafeNica: California

Kondamundi, N., Mohapatra, S. K., and Misra, M., 2008 Spent Coffee Grounds as a Versatile Source of Green Energy, Journal of Agricultural and Food Chemistry Vol 56, No. 24, pp11757-11760

Mance, H., 2009 Colombians find redemption in coffee

Mazzafera, P., Soave, D., Teixeira, M. A. Z., and Guerreiro Filho, O., 1998 Oil Content of Some Green Coffee Species Bragantia, Vol 57, No.1 Instituto Agronomica de Campinas

Oliveira, L. S., Franca, A. S., Mendonça, J. C. F., Barros-Junior, M. C., 2005 Proximate composition and fatty acids profile of green and roasted defective coffee beans LWT Vol. 39, pp 235-239

Oliveira, L.S., Franca, A.S., Camargos, R.R.S., Ferraz, V.P., 2007 Coffee Oil as a potential feedstock for biodiesel production Bioresource Technology Vol. 99 pp3244-3250

Ponte, S., 2002 The Latte Revolution? Regulation, Markets and Consumption in the Global Coffee Chain World Development, Vol. 30, No. 7 pp1099-1122

Santa Emilia, 2006 Manual de Catacion Santa Emilia Estate: Nicaragua

Wallengren, M., 2008 Nicaraguan Coffee Harvest Down 41% on Previous Year, Dow Jones Newswires

With thanks to Julio Absalon Obregon at Cecocafen, Matagalpa, Nicaragua for information on Cafè El Sabor Nica

The Waste of the World is funded by the ESRC.


Posted by on January 24, 2009 in Uncategorized