Coffee & Conservation — Are your beans for the birds?

Sustainable coffee is produced on a farm with high biological diversity and low chemical inputs. It conserves resources, protects the environment, produces efficiently, competes commercially, and enhances the quality of life for farmers and society as a whole.
-- Smithsonian Migratory Bird Center, First Sustainable Coffee Congress.

The curse of the spud

January 27, 2012

“Potato taint” in African coffees

Some East African coffees, especially those from Rwanda, but also Burundi, Tanzania, Zambia, and Kenya, are afflicted by the strong flavor of potato peels, not a desirable taste in coffee. This defect is said to be ultimately caused by one of the pyrazine chemical compounds. How do coffee beans end up with this chemical? The prevailing theory is that coffee cherries are damaged by insects, most notably several species of stink bugs. The damage facilitates contamination of the cherry, which leads to formation of the potato taint compounds.

The connection between the bugs and the taint are not completely understood. Let’s take a super-geeky look at what we know about the bugs — which, whether they cause the potato defect or not, do a lot of damage to coffee cherries — and how they might be responsible for the potato taint.

Bugs that make a stink

The insects that cause damage to coffee cherries in East Africa that are usually associated with potato taint are in the order Hemiptera, the true bugs. This order includes various bugs that suck plant juices, including cicadas, leafhoppers, aphids, scale insects, shield or stink bugs, and many others. The stink bugs that are coffee pests are collectively called “Antestia bugs,” after their former generic name (many species in the genus Antestia have been reclassified under another genus, Antestiopsis). Two primary culprits are Antestiopsis orbitalis (formerly Antestia lineaticollis) and Antestiopsis intricata.

A. orbitalis (above right) is a colorful bug about 7 mm long. Various subspecies have slightly different patterns. This and related species that also attack coffee have similar life histories; for the sake of simplicity I’ll refer to them collectively as variegated coffee bugs. Some species are found in India and southeast Asia. We’ll focus on the ones usually found in Africa.

Three variegated coffee bugs on coffee in Burundi. Photo by Tim Hill of Counter Culture Coffee.

Variegated coffee bugs can complete four generations a year, and reproduce best at temperatures between 19 and 24 degrees C (66-75 F) and humidity between 35-50%. Eggs are laid on the undersides of leaves. The young are called nymphs, and are similar, but smaller, than the adults. Average life span is three to four months. Like all Hemipterans, variegated coffee bugs have piercing mouthparts adapted to sucking plant juices. Arabica coffee (rarely robusta) is the preferred host, but other plants in the coffee family (Rubiaceae) are also used. Variegated coffee bugs feed on shoots and leaves (causing damage and bud drop) but primarily on unripe coffee cherries.

Not only does this type of feeding itself cause physical damage to the cherry, but fungi (yeast) in the genus Nematospora (N. [=Eremothecium] coryli and N. [=Ashbya] gossypii) can secondarily infect the cherry. Nematospora fungi are not specific to coffee, but when these two species infect coffee, it’s usually called coffee bean rot. The fungi only cause rot in unripe (green) cherries.

It’s believed that the bugs are vectors of the fungi; that is,the bugs carry the spores and the fungi are dependent on the bugs (though not variegated coffee bugs exclusively) for dispersal. There is some dispute over whether the spores are present internally in the bugs and thus inoculated into plants, or if they are present on the surface of the bugs. Not all cherries pierced by the bugs become infected. It could be that the fungal spores are not present in/on all bugs, or that if they are present internally, they may be too large to pass through the mouthparts of younger (smaller) individuals.

Physical damage to the coffee cherry and the associated rot cause significant losses (up to 45%) on coffee farms infested with variegated coffee bugs. Do these bugs also cause potato taint?

Chemicals that make a stink

A number of chemical compounds produce potato-like odors. The most notable is a methoxypyrazine: 2-methoxy 3-isopropylpyrazine (or “MIPP”*). The odor threshold of MIPP is very low, so it’s easily detected in very small quantities. MIPP has been found in nature in some plants and higher organisms. Various pyrazines can be synthesized chemically and biologically, and MIPP has been produced by cultures of at least one bacteria, Pseudomonas perolens.

Other Pseudomonas cultures also have potato odors. This group of bacteria are free-living, and widely found in soil and water (at least one strain infects the leaves of coffee trees). Several other bacteria, such as some strains of Serratia and Cedecea, produce potato-like odors that are the result of a combination of pyrazine compounds.

Despite my access to vast quantities of scientific literature, I was surprised to find virtually no published research on the chemical processes of coffee bean rot. Does it produce MIPP or a similar compound with a potato odor? If other bacteria are involved in the potato defect, are they connected in some way to the fungal infection that is typically introduced by variegated coffee bugs? Where to the bacteria come from?

One very interesting clue comes from Tim Hill, of Counter Culture Coffee, who provided the photo above left. He said that the potato odor was apparent in the air during a rainstorm in Burundi. This is suggestive that a/the taint-producing bacteria may be present in the soil. While I have been unable to pin down the range of Pseudomonas perolens, there are nearly 200 species of this bacteria worldwide. I have to wonder why the potato defect is largely (exclusively?) considered an East African problem and why it has been historically linked to variegated potato bugs, but not, for instance, coffee berry borers which also penetrate the green cherry. The borers and Pseudomonas are fairly ubiquitous in coffee-growing nations. It seems to me that there must be a link between the variegated coffee bugs and a bacteria that facilitate the production of stinky pyrazine compounds.

Bringing us to this compelling clue: MIPP (usually going by its synonym IPMP*), is found in some grapes and contributes to pleasant flavors in wines in small amounts, but at higher levels is associated with the off-flavor known as “ladybug taint.” The ladybugs (Asian multicolored lady beetles, Harmonia axyridis, the non-native species that can be a household pest) do not actually attack or harm the grapes. IPMP is part of the chemical make-up of the ladybugs, and when the insects get mixed in and processed with the grapes, the taint occurs in the wine.

IPMP is present in lots of ladybug species, and many other insects that are “aposematic” — those possessing some kind of warning signal to potential predators. Usually, this is some sort of bright coloration, very often red and black. I have not seen any variegated coffee bugs or close relatives on lists of insects that have been confirmed to have any pyrazines, but their colorful patterns are consistent with other aposematic insects, and some other Hemiptera are classified as aposematic. Recall this group of bugs is known as “stink bugs.” This is precisely because most have the ability to release a nasty chemical when molested. So further exploration of the chemical make-up of variegated stink bugs surely seems a promising avenue of research.

However these compounds end up in the coffee cherry, they end up altering the bean, which itself does not show damage. (This fact — that the damaged cherries must be identified and discarded prior to processing, after which they cannot be detected until the coffee is roasted or ground — is what makes this defect so frustrating.)

Recent news out of the University of California, Riverside announced that one of their entomologists was going to Rwanda to help solve the mystery of the potato defect. That item said, “there is no definitive link between potato taste and antestia bug, only hypotheses.” While the research I’ve cited (see below) is not very current, the dots seem to be connected right up to the end point of why and how MIPP or a similar compound is produced.

The battle of the bug

Given the fact that one way or another, variegated coffee bugs are pests of coffee, control methods for them will continue to be important. Fungicides do not control the type of infection caused by Nematospora, given that the fungi are introduced within the coffee cherry. Small infestations of the bugs can been battled with hand-picking. Since the bugs like dense foliage, pruning is often recommended. In the long run, both natural and synthetic pyrethrum insecticides have proven ineffective in many cases. The bugs have typically been controlled with multiple applications of pesticides, usually fenitrothion, chlorpyrifos, malathion, trichlorfon, and diflubenzuron. All but the last are organophosphate pesticides that are especially dangerous (to humans and the environment) when not applied according to instructions with full protection, which is often not the case in less-developed nations.

Fortunately, because they are native to East Africa, variegated coffee bugs do have many natural enemies which may be exploited for biocontrol; they are especially vulnerable to a number of native parasitic wasps that attack the eggs. With persistence and luck, reliable biological and cultural control of variegated coffee bugs will hopefully be developed.

As the Rwandan and Burundian specialty coffee sectors grow, the urgency to defeat the potato taint will grow. I’ll be following any progress and research on the exact mechanisms of potato taint and any methods of control and detection that emerge.

Photo of Antestiopsis orbitalis by Lambert Smith, used with permission.

*This compound has several synonyms: 2-Isopropyl-3-methoxypyrazine, 3-Isopropyl-2-methoxypyrazine, or IPMP. The CAS Registry number is 25773-40-4.

Further reading:

Coffeed forum thread, “The Rwandan Potato problem,” June 2007.

James Hoffman, “The Phantom Potato,” February 2009 blog post. This post and the comments, and the forum post above talk about potato taint from the barista/consumer perspective in particular. Below, is some of the primary academic and scientific literature.

Cheng, T.-B., G. A. Reineccius, J. A. Bjorklund, and E. Leete. 1991. Biosynthesis of 2-methoxy-3-isopropylpyrazine in Pseudomonas perolens. J. Agric. Food Chem. 39:1009-1012.
Cilas, C., B. Bouyjou, and B. Decazy. 1998. Frequency and distribution of Antestiopsis orbitalis Westwood (Hem., Pentatomidae) in coffee plantations in Burundi: implications for sampling techniques. Journal of Applied Entomology. 122:601-606.
Crowe, T.J., G.D.G. Jones, and R. Williamson. 1961. The use of pyrethrum formulations to control Antestiopsis on coffee in East Africa. Bulletin of Entomological Research. 52:31-41.
Greathead, D.J. 1966. A taxonomic study of the species of Antestiopsis (Hemipteea, Pentatomidae) associated with Coffea arabica in Africa. Bulletin of Entomological Research. 56:515-554.
Kirkpatrick, T. W. 1937. Studies on the ecology of coffee plantations in East Africa. Ii. the autecology of Antestia Spp. (pentatomidae) with a particular account of a Strepsipterous parasite. Transactions of the Royal Entomological Society of London 86:247-343.
Le Pelley, R.H. 1932. On the control of Antestia Lineaticollis, Stål (Hem., Pentatom.) on Coffee in Kenya Colony. 1932. Bulletin of Entomological Research. 23:217-228.
Le Pelley, R.H. 1942. The food and feeding habits of Antestia in Kenya. Bulletin of Entomological Research. 33:71-89.
McNutt, D.N. 1979. Control of Antestiopsis spp. on coffee in Uganda. Tropical Pest Management. 25:5-15.
Mehrotra, R. S., and Aggarwhal, A. 2003. Plant Pathology, 2nd Ed. Tata McGraw-Hill, New Delhi.
van der Meulen, H.J., and A.S. Schoeman. 1990. Aspects of the phenology and ecology of the antestia stink bug, Antestiopsis orbitalis orbitalis (Hemiptera: Pentatomidae), a pest of coffee. Phytophylactica. 22:423-426.
Mitchell, P.L. 2004. Heteroptera as vectors of plant pathogens. Neotropical Entomology. 33:519-545.
Nixon, G.E.J. 1941. New Braconid parasites of Antestia Lineaticollis, Stål, and of Sylepta Derogata, F. Bulletin of Entomological Research. 32:93-101.
Pickering, G. J, M. Spink, Y. Kotseridis, D. Inglis, I. D. Brindle, M. Sears, and A. Beh. 2008. Yeast strain affects 3-isopropyl-2-methoxypyrazine concentration and sensory profile in Cabernet Sauvignon wine. Australian Journal of Grape and Wine Research. 14:230-237.

Posted in Coffee regions,Research on coffee growing

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Site updates

January 25, 2012

I’ve recently done some tweaks and improvements of the foundation and background information on the site:

I’ve updated some of the important primary background posts: What is shade-grown coffee?, The problems with sun coffee, and Birds and coffee plantations.
I’ve updated the post on where to get Smithsonian Bird-Friendly certified coffee.
I’ve streamlined the User Guide page, which lists the nuts and bolts posts that provide an overview on what you need to know about sustainable coffee.
I’ve made many additions to the list of peer-reviewed literature on sustainable coffee issues. While I review some research articles here, the bibliography lists many more that are published on coffee pests and diseases, shade management, biodiversity on coffee farms, the economics of various certifications, climate change and coffee, and related topics. You can always access it via the “References” tab at the top of the page. If you have a paper you are especially interested in that you can’t access without an academic account, write to me and I can probably get you a copy.

Posted in Housekeeping

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Rainforest Alliance Cupping for Quality – Dec 2011

January 21, 2012

The Rainforest Alliance Cupping for Quality award is designed to recognize exceptional coffees carrying the Rainforest Alliance seal and to highlight the linkage between sustainable farm management practices and cup quality. There are now two annual cuppings and awards, divided by geography. In December, coffees from the southern hemisphere — including Brazil, Peru, Kenya, Tanzania and Indonesia — compete. These are the results of the December 2011 cupping.

This year, there were 45 coffee samples from eight origins submitted.

Tunki, Peru (87.92). This organic, Fair Trade coffee, from the Tunkimayo sector in Puno, also won in 2009. It consists of mostly typica and bourbon grown at 1300 to 1800 m. Tunki is one of the coffees from CECOVASA (Central de Cooperativas Agrarias Cafetaleras de los Valles de. Sandia), a group of cooperatives totaling nearly 5000 members. CECOVASA has been working with Conservation International, and has won an award for their work preserving biodiversity. “Tunki” is the local name for the national bird of Peru, the spectacular Andean Cock-of-the-Rock, depicted in their logo. Equal Exchange has a good article on a visit to CECOVASA. Peru is not one of my favorite origins, but I had this coffee at a blind tasting at an SCAA event, and it was outstanding. It’s available here; there’s also a Facebook page.
Deep River, Kwanyoka Estate, Kenya (86.06).
Ururi, Peru (85.25). This is another organic, Fair Trade CECOVASA coffee (see #1, above), grown at 2000 m from the Pata Inambari Valley. As outlined in this Equal Exchange post, CECOVASA has really been working on quality. Just two years ago, Ururi only scored at 75.48 in the Cupping for Quality competition. What an improvement!
Mihando, Kenya (85.19).
Madan Coffee Plantation, Papua New Guinea (84.56). Located in the Western Highlands of PNG, this 320 ha, privately-owned estate was acquired by Highland Arabicas in 2003. They grow primarily Blue Mountain typica, but also Arusha and Mundo Novo.
Githaka, Kenya (84.50).
Kihuri Estate, Kenya (84.41).
Machure Estate, Kenya (84.33).
Muthaite, Kenya (84.31).
Parry Estate, Kona Gold Coffee Plantation, USA (Hawaii) (84.25). A family-owned, 354 ha estate at 610 m on Kona (not to be confused with Perry Estate, also on Kona).

I have accumulated detailed data on the Cupping for Quality competition going back to 2007. Including these current results, this consists of seven competitions because Rainforest Alliance went from one to two annual cuppings in 2009. While not all countries were represented in each competition, even within the geographically-limited events, the mix of countries changes from one year to the next. So while this isn’t a totally homogenous data set, the numbers I’ve compiled are still interesting.

The average score for the top ten in this current event was 85.08, which is slightly below the previous average of 85.22. The top score of 87.92 was also below the average of previous top scores (88.35). So far (as this data goes), none of the scores has broken 90 points yet. I don’t think this is necessarily a reflection on the quality of Rainforest Alliance-certified coffees in general. Not all farms compete, and some well-known certified farms don’t or haven’t competed for some time. In fact, I suspect that some of the well-known farms don’t feel they need to, and that entrants may be biased toward up-and-comers that are striving for recognition.

Congratulations to all these farms for their commitment to sustainability and quality.

The next round will be announced in late April at the SCAA event, after which I’ll update the averages and perhaps present some additional data.

Posted in Coffee awards and competitions,Rainforest Alliance

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Market share update: Certified purchases

January 16, 2012

How much eco-certified coffee is purchased by the big coffee companies?

In late 2010, I posted data on how ~~much~~ little sustainably-grown coffee was purchased by the world’s major coffee buyers. The post utilized mostly 2008 data, much of which came from a terrific publication, The Coffee Barometer 2009, which was put out by the Tropical Commodity Coalition. Unfortunately, there was no Coffee Barometer 2010, nor will there be any in the years to follow since the TCC has now disbanded. I’m going to try to take up the mantle with periodic updates.

Methods

I’m going to focus on the four major world buyers: Nestlé, Kraft, JM Smuckers, and Sara Lee. I will also include Starbucks, as a major world buyer; Green Mountain Coffee Roasters, which holds a top market share in the U.S.; and Caribou Coffee, the second-largest U.S. coffeehouse. Other players, some of which were mentioned in the previous post, are primarily European, or the data is not disclosed or difficult to uncover.

I’m going to consider eco-certifications or standards only: Rainforest Alliance and organic; since Smithsonian Bird-Friendly is produced in such tiny volumes and must be certified organic, it is included in the organic category. I also note Starbucks CAFE Standards. Although it only applies to Starbucks coffee, it includes good environmental criteria. I’ll disregard coffee purchased under Fair Trade and the 4C Code, neither of which have strong/meaningful environmental standards. I’ll mention but not count towards percentages Utz Certified and Nespresso’s AAA Program. You can read about all of these certifications and criteria on my certifications guide page.

Data sources will be linked (2008 data sources are in the previous post), or included in the footnotes. I’ve converted volumes to metric tons for comparison; some volumes and percentages are calculated or extrapolated from closely related figures.

Company	Market Share	Purchases*	Certified purchases
*Note that often reporting is done by fiscal, rather than calendar, year. I've looked for the most recent data, which generally covers much of calendar year 2010.
Nestlé Brands owned include Nescafé, Nespresso, Taster’s Choice, Clasico.	Global share of packaged coffee 21.6% (2009). U.S. share 16.3%.¹	2008: 780,000 tons 2010: 820,000 tons ² (56,373 tons was Nespresso³)	None. See note below.
Nestlé offers no organic varieties. A page on the Nescafé website talks about organic coffee without ever stating it is bought or sold by the company. In the previous post, I noted 13,000 tons (or 1.7%) were purchased under their proprietary Nespresso AAA Sustainable Quality program. For what it's worth, in June 2011, Nespresso reported³ it sourced 28,911 tons under the AAA program in 2010. This represents 3.5% of Nestlé's total purchases. Unfortunately, the criteria or standards for this program are not publicly available. They were developed in cooperation with Rainforest Alliance, but Nespresso states that their program was developed to improve quality, while Rainforest Alliance standards focus on protecting the environment. Nespresso has indicated that they are now working to help groups of farmers get Rainforest Alliance certification so the farmers can get more money for the coffee they choose not to sell to Nespresso⁴(my emphasis added). In August 2011, The Nescafé Plan was announced, which set a goal of sourcing 90,000 tons "according to Rainforest Alliance and Sustainable Agriculture Network principals" by 2020. It's unclear if that means certified coffee, or some set of standards that use the Rainforest Alliance criteria as guidelines. Under the best-case scenario, if all 90,000 tons of Nescafé purchases plus all 56,373 tons of Nespresso purchases were 100% RA-certified, it would still represent less than 18% of Nestlé's total purchases.
Kraft Brands owned include Yuban, Maxwell House, General Foods International Coffee, Gevalia, Kenco, Maxim, Tassimo, Nabob, and Sanka.	Global: 13.6% (2009). U.S.: 17.6%.¹	2008: 740,000 tons 2010: data not available	2008: 29,500 tons Rainforest Alliance (4%) 2010: 50,000 tons Rainforest Alliance
If Kraft purchased approximately the same total amount of coffee in 2010 as it has in the past, the Rainforest Alliance certified portion has increased to 6.7%. Some of Kraft coffees are organic, so either some of the Rainforest Alliance total is also organic, or there is some additional volume certified organic only.
JM Smuckers Brands owned include Folgers and Millstone (acquired from Procter & Gamble in 2008); Kava; Dunkin Donuts grocery store coffee; Rowland Coffee brands (acquired in 2011) including Café Bustelo and Café Pilon. In early 2012, Smuckers also purchased Sara Lee's North American foodservice coffee operations including Java Coast, and various convenience store, restaurant, and institutional accounts.	Global: 2.4% (2009). U.S.: 22.0%.¹ (prior to Sara Lee acquisition).	2008: 280,000 tons (prior to acquistions) 2010: data not available	2008: 1,500 tons (0.5%) was certified either Rainforest Alliance, Fair Trade, and/or organic. 2010: data not available. See note.
The Sara Lee UTZ Certified "Good Origin" coffee was available via foodservice in the U.S.; whether Smuckers will continue to offer or source it isn't known at this time. Smuckers is buying up coffee operations, which now make up the largest portion of the company's product sales. In addition to buying hardly any certified coffee of any sort, Smuckers has the worst sustainability initiative and reporting of all major coffee companies. They don't even bother with quality programs or greenwashing.
Sara Lee/Douwe Egberts Brands include Senseo, Merrild, Kanis & Gunnink, Cafe Pilao, Cafitesse, Harris, Piazza d’Oro.	Global: 5.4% (2009). U.S.: 4.1%.¹	2008: 450,000 tons 2010: 200,000 tons ⁶	2008: Some organic; amount unknown. 20,000 tons (4.4%) UTZ Certified (see note). 2010: Some organic; amount unknown. 40,000 tons UTZ Certified (20%)⁶.
Sara Lee is divesting itself of all North American coffee operations. Much has gone to Smuckers. As of March 2012 it will discontinue Senseo coffee pod business in the U.S. as well. The company is the largest buyer of UTZ Certified coffee. This certification deserves credit for its transparency requirements, and for what I hear is an evolution toward more environmental criteria, but right now it can't be considered an eco-standard.
Starbucks	Global: 1.8% (2009). U.S.: 11.8%.¹	2008: 175,000 tons 2010: 122,000 tons	2008: 4,500 tons organic (2.6%); 120,500 tons under their CAFE Practices (68.8%). I gave a combined total of 71.4%, but some may overlap. 2010: About 3.6% organic (see note) plus 103,000 tons (84%) under CAFE Practices.
The environmental standards of Starbucks CAFE Practices preferred buyer program are more detailed and stronger than many third-party certifications, including Fair Trade and UTZ Certified. In 2009, Starbucks stated they purchased 6350 tons (3.8%) of certified organic coffee. This was before they discontinued their Organic Shade-grown Mexico. Figures are not given for 2010, although at one time I saw a figure of 3.6%. This proportion is probably about correct, even if they are buying less organic coffee, because their overall purchases were less in 2010.
Green Mountain Coffee Roasters Brands include Timothy's Coffee of the World, Tully's, Diedrich, Coffee People, Gloria Jean's, Van Houtte, and Newman's Own.	U.S.: 14.1%.¹	2008⁵: 18,439 tons 2010⁵: 22,282 tons	2008 ⁵: 4133 organic 2010⁵: 5006 tons organic (22.5%).
Latest figures are for fiscal year 2009; GMCR fiscal years end in September.
Caribou Coffee		2010: 9100 tons	2010: 9100 tons Rainforest Alliance (100%)
Caribou is the first major coffeehouse to source 100% Rainforest Alliance (or any eco-certified) coffee. See this post for details.