Commentary Digested Beans ( Luwak)—An Unfortunate Trend in Specialty Coffee Caused by Mislabeling of liberica?

Dirk W. Lachenmeier 1,* and Steffen Schwarz 2

1 Chemisches und Veterinäruntersuchungsamt (CVUA) Karlsruhe, Weissenburger Strasse 3, 76187 Karlsruhe, 2 Coffee Consulate, Hans-Thoma-Strasse 20, 68163 Mannheim, Germany; [email protected] * Correspondence: [email protected]; Tel.: +49-721-926-5434

Abstract: In the context of protection, the trend of digested such as produced by civet in captivity should not be endorsed. Previous studies on such coffees may have been flawed by sample selection and misclassification. As wild may prefer beans, due to their higher content, the chemical differences may be caused by the Coffea difference combined with a careful selection of ripe, defect-free cherries by the , rather than changes caused by digestion. This may also explain the observed differences between Kopi Luwak from wild civets (mainly C. liberica) compared to the one from animals in captivity (typically fed with C. arabica and/or C. canephora).

Keywords: coffee; ; ; Kopi Luwak; civet  

Citation: Lachenmeier, D.W.; Schwarz, S. Digested Civet Coffee 1. Introduction Beans (Kopi Luwak)—An The topic of digested coffees is currently receiving a renewed interest and has recently Unfortunate Trend in Specialty Coffee been proposed as a “new trend in specialty coffee” [1]. Caused by Mislabeling of Coffea liberica? In this commentary, we want to point out the interesting issue of Coffea species Foods 2021, 10, 1329. https://doi.org/ assignment in the context of digested coffee studies. The first problem emerges when 10.3390/foods10061329 chemical studies are conducted in non-coffee growing countries, and sampling relies on commercial suppliers, often with doubtful authenticity. The control group is also Academic Editor: problematic in the digested coffee studies, as wild civets may select the sweetest, most ripe, Raúl González-Domínguez and healthy cherries, while the control coffee of commercial quality may include different

Received: 11 May 2021 stages of ripeness and the typical amount of defective beans. For example, it makes no Accepted: 7 June 2021 to use a Brazilian C. arabica coffee as control group for Kopi Luwak from . Published: 9 June 2021 Geographical and variety differences within C. arabica alone may explain the observed differences.

Publisher’s Note: MDPI stays neutral The second problem with digested coffees is that many studies may have missed that with regard to jurisdictional claims in the actual coffee species under investigation has been Coffea liberica, not or published maps and institutional affil- , which has been incorrectly assumed. This hypothesis was first raised iations. during an international roasting competition for Liberica coffee [2].

2. A Short Critique of Previous Digested Coffee Studies The study of Marcone [3] is currently the most widely cited study on digested coffees

Copyright: © 2021 by the authors. according to Google Scholar (187 citations in June 2021). Marcone [3] obtained Kopi Licensee MDPI, Basel, . Luwak and control beans (not having gone through the palm civet) from a supplier in This article is an open access article California. Both the Kopi Luwak and control coffee beans were claimed as being Indonesian distributed under the terms and Coffea canephora var. robusta. The study also included coffee collected in conditions of the Creative Commons western Ethiopia. No species was provided for the Ethiopian coffee, which, however, Attribution (CC BY) license (https:// should be assumed as being Coffea arabica, the predominant species in Ethiopia. Marcone [3] creativecommons.org/licenses/by/ provided photographs of the studied beans (reproduced in Figure1a–c). 4.0/).

Foods 2021, 10, 1329. https://doi.org/10.3390/foods10061329 https://www.mdpi.com/journal/foods Foods 2021, 10, x FOR PEER REVIEW 2 of 4

Foods 2021, 10, 1329 should be assumed as being Coffea arabica, the predominant species in Ethiopia. Marcone2 of 4 [3] provided photographs of the studied beans (reproduced in Figure 1a–c).

FigureFigure 1. 1. PhotographsPhotographs of of coffees coffees claimed claimed as as being being digested: digested: ( (aa)) Kopi Kopi Luwak Luwak coffee coffee beans beans (claimed (claimed asas being being CoffeaCoffea canephora canephora var.var. robusta), robusta), (b) ( bNekemte-African) Nekemte-African Civet Civet coffee coffee beans, beans, and and (c) Abdela-Af- (c) Abdela- ricanAfrican Civet Civet coffee coffee beans. beans. Photographs Photographs of non-digested of non-digested coffees coffees for forcomparison: comparison: (d) Coffea (d) Coffea liberica, liberica, (e) Coffea(e) Coffea canephora canephora var. var.Old OldParadenia Paradenia (), (India), and ( andf) Coffea (f) Coffea arabica arabica var. Catuaívar. Catua Vermelhoí Vermelho (Brasil). (Brasil). ((a– c(() areprinted–c) reprinted with with graphical graphical improvement improvement (background (background and andnoise noise removed) removed) from from Food Food Research Research In- ternational,International, 37, 37, Massimo Massimo F. F.Marcone, Marcone, Composition Composition and and properties properties of of Indonesian Indonesian palm palm civet civet coffee coffee (Kopi Luwak) and Ethiopian civet coffee, pp. 901–912 [3], Copyright (2004), with permission from (Kopi Luwak) and Ethiopian civet coffee, pp. 901–912 [3], Copyright (2004), with permission from Elsevier. (d–f) are original photographs). Elsevier. (d–f) are original photographs).

AccordingAccording to to Marcone Marcone [3], [3], the the beans beans were were assigned assigned as as C.C. canephora (Figure(Figure 11a),a), andand twotwo types types of of Ethiopian Ethiopian coffee coffee (Figure (Figure 11b,c).b,c). However according to ourour assessmentassessment ofof thethe shapes,shapes, the the beans beans are are actually actually C.C. liberica liberica (Figure(Figure 11a),a), C.C. canephora canephora (which(which is is rather rather unusual unusual forfor Ethiopia, Ethiopia, therefore therefore assumed assumed as asan anadulterated adulterated product) product) (Figure (Figure 1b),1 andb), andC. arabicaC. arabica (Fig- ure(Figure 1c). Please1c). Please note notethe bulging the bulging and raised and raised nature nature of the ofbeans the at beans the cut at thefor liberica cut for liberica(Figure 1a).(Figure Arabica1a). Arabica and canephora and canephora are flat areat the flat cut at theand cut equally and equally high on high both on sides. both sides.In our In opin- our ion,opinion, the mislabeling the mislabeling is quite is quiteclear. clear.For comp Forarison comparison purposes, purposes, we provide we provide examples examples of au- thenticof authentic C. libericaC. liberica (Figure(Figure 1d), C.1d), canephoraC. canephora (Figure(Figure 1e) and1e) andC. arabicaC. arabica (Figure(Figure 1f). The1f). Thefact thatfact C. that libericaC. liberica exhibitsexhibits such sucha little-noticed a little-noticed existence existence is surely is surely one of one the of reasons the reasons why whythis circumstancethis circumstance escaped escaped the authors the authors of Kopi of KopiLuwak Luwak studies studies and reviews and reviews [1] thus [1] far. thus The far. speciesThe species difference difference may mayalso explain also explain the differen the differentt surface surface morphology morphology of the of beans the beans [3]. The [3]. discriminationThe discrimination ability ability of some of someanalytical analytical methods methods can also can be also explained be explained in that intwo that differ- two entdifferent coffee coffee species species were werecompared compared against against each eachother other (i.e., (i.e.,C. libericaC. liberica in Kopiin Kopi Luwak Luwak vs. C. vs. arabicaC. arabica as controlas control group, group, e.g., e.g., compare compare Jumhawan Jumhawan etet al. al. [4–6] [4–6 and] and Suhandy Suhandy and and Yulia Yulia [7]). [7]).

3.3. Kopi Kopi Luwak Luwak a a CoffeaCoffea liberica liberica inin Disguise? Disguise? TheThe distinctly distinctly different different taste and and highly highly va valuedlued flavor flavor of of Kopi Kopi Luwak Luwak coffee coffee may may be be causedcaused by the purepure factfact that that it it is isCoffea Coffea liberica liberica, which, which has has a completely a completely different different flavor, flavor, with withvery complexvery complex profile profile compared compared to the commercialto the commercial coffee species coffee C.species arabica C.and arabicaC. canephora and C. . canephoraC. liberica. C.has liberica the highest has the sugar highest content sugar ofcontent all coffees, of all coffees, and thus and has thus the has highest the highest risk of riskfermentation. of fermentation. The sugar The sugar content content may also may be al theso be reason the reason that the that civets the civets and other and coffeeother coffeeconsuming consuming animals animals prefer preferC. liberica C. libericaover over the other the other species, species, if they if they are availableare available in the in thesame same area. area. DiligentlyDiligently prepared prepared C.C. liberica liberica showsshows intense intense fruity fruity and and floral floral notes notes (strawberry, (strawberry, jack- jack- fruit,fruit, , mango, banana) banana) and and a a lactic lactic character character (yogurt, (yogurt, cream, cream, mascarpone, mascarpone, crème crème fraiche) fraiche) with a pronounced body and intense . When roasted too dark, the coffee offers notes that reach into the realm of ripe, sweet blue cheese and cheddar. The lactic, cheesy, perhaps also animalic character of C. liberica may be easily misinter- preted as an influence potentially caused by animal digestion or intra-animal fermentation Foods 2021, 10, x FOR PEER REVIEW 3 of 4

with a pronounced body and intense sweetness. When roasted too dark, the coffee offers Foods 2021, 10, 1329 notes that reach into the realm of ripe, sweet blue cheese and cheddar. 3 of 4 The lactic, cheesy, perhaps also animalic character of C. liberica may be easily misin- terpreted as an influence potentially caused by animal digestion or intra-animal fermen- (i.e.,tation the (i.e., alleged the alleged change change in taste in caused taste caus byed digestive by digestive enzymes enzymes of the of animals), the animals), which which are notare convincinglynot convincingly proven proven in previous in previous scientific scient studies.ific studies. Currently, Currently, there there are noaresensory no sensory or chemicalor chemical studies studies available available investigating investigating the th possibilitye possibility to to distinguish distinguish Kopi Kopi Luwak Luwak from from regularregular coffee coffee prepared prepared from fromCoffea Coffea liberica libericaspecies. species. OneOne of of the the first first descriptions descriptions of of Kopi Kopi Luwak, Luwak, from from Brehm Brehm in in 1883 1883 [ 8[8],], suggested suggested that that thethe civetcivet releasedreleased the undigested undigested seeds, seeds, that that the the excrement excrement consisted consisted entirely entirely of caked, of caked, but butincidentally incidentally undamaged undamaged coffee coffee beans, beans, and andthat thatthe animals the animals provide provide the very the best very coffee best coffeebecause because they ate they the ateripest the fruits. ripest This fruits. descript Thision description stands largely stands unchallenged largely unchallenged to this day, toand this the day, scientific and the proof scientific for proofthe alternative for the alternative hypothesis, hypothesis, that animal that digestion animal digestion actually actuallychanges changes the coffee the and coffee its andflavor its profile, flavor profile,so far lacks so far convincing lacks convincing proof. proof.Due toDue the animal to the animalcruelty cruelty involved, involved, we believe we believe that this that question this question does not does necessarily not necessarily need further need furtherinvesti- investigation.gation. Ripe and Ripe sweet and sweetcoffee coffee cherries cherries of C. oflibericaC. liberica may maybe selected be selected by means by means other other than thanthe use the of use animals. of animals.

4.4. ConclusionsConclusions TheThe authors authors believe believe that that digested digested coffee coffee is is rather rather a a pervertedperverted trendtrend inin specialtyspecialty coffee,coffee, especiallyespecially ifif thethe civet cats are are kept kept in in captiv captivityity purely purely for for the the purpose purpose of ofcoffee produc- tion[9] (Figure [9] (Figure 2). In2). this In regard, this regard, it is almost it is almost a relief a reliefthat much that muchcoffee coffeelabelled labelled as “Kopi as Luwak” “Kopi Luwak”is probably is probably a counterfeited a counterfeited product product that has that never has seen never the seen digestive the digestive tract of tract an animal of an animal(42% of (42% Kopi of Luwak KopiLuwak were claimed were claimed as being as found being to found be either to be complete either complete fakes or fakes adulter- or adulteratedated with regular with regular coffee coffeebeans beans[10]). [10]).

FigureFigure 2. 2.Civet Civet kept kept caged caged for for Kopi Kopi Luwak Luwak production production (attribution: (attribution: author author Surtr, Surtr, (https://commons. license CC BY-SA 2.0, via Wikimedia Commons). wikimedia.org/wiki/File:Luwak_(civet_cat)_in_cage.jpg accessed on 8 June 2021) license CC BY-SA 2.0, (https://creativecommons.org/licenses/by-sa/2.0/ accessed on 8 June 2021) via Wikimedia Commons).

Hopefully, the observation that an already valued specialty coffee such as Kopi Luwak may actually be Coffea liberica will encourage a new debate on this species in coffee culti- vation, especially against the backdrop of climate change. It would certainly be desirable Foods 2021, 10, 1329 4 of 4

for the diversity of flavors in coffee, as well as avoid animal cruelty for an unnecessary procedure.

Author Contributions: Conceptualization, D.W.L. and S.S.; writing—original draft preparation, D.W.L.; writing—review and editing, S.S. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Data Availability Statement: No new data were created or analyzed in this study. Data sharing is not applicable to this article. Conflicts of Interest: S.S. is owner of Coffee Consulate, Mannheim, Germany. Coffee Consulate is an independent training and research center. Coffee Consulate is not commercializing digested coffees. Therefore, S.S. reports no conflicts of interest related to the work under consideration. D.W.L. declares no conflicts of interest.

References 1. Raveendran, A.; Murthy, P.S. New trends in specialty coffees—“The digested coffees”. Crit. Rev. Food Sci. Nutr. 2021, 61. [CrossRef] 2. Coffee Consulate. Liberica Coffee International Roasting Competition 2019; Coffee Consulate: Mannheim, Germany, 2019; Avail- able online: https://www.coffee-consulate.com/media/09/59/e8/1592404961/Booklet_LibericaRoastingCompetition2019.pdf (accessed on 8 June 2021). 3. Marcone, M.F. Composition and properties of Indonesian palm civet coffee (Kopi Luwak) and Ethiopian civet coffee. Food Res. Int. 2004, 37, 901–912. [CrossRef] 4. Jumhawan, U.; Putri, S.P.; Yusianto; Bamba, T.; Fukusaki, E. Quantification of coffee blends for authentication of coffee (Kopi Luwak) via metabolomics: A proof of concept. J. Biosci. Bioeng. 2016, 122, 79–84. [CrossRef][PubMed] 5. Jumhawan, U.; Putri, S.P.; Yusianto; Bamba, T.; Fukusaki, E. Application of gas chromatography/flame ionization detector-based metabolite fingerprinting for authentication of Asian palm civet coffee (Kopi Luwak). J. Biosci. Bioeng. 2015, 120, 555–561. [CrossRef][PubMed] 6. Jumhawan, U.; Putri, S.P.; Yusianto; Marwani, E.; Bamba, T.; Fukusaki, E. Selection of discriminant markers for authentication of Asian palm civet coffee (Kopi Luwak): A metabolomics approach. J. Agric. Food Chem. 2013, 61, 7994–8001. [CrossRef][PubMed] 7. Suhandy, D.; Yulia, M. The use of partial least square regression and spectral data in UV-visible region for quantification of adulteration in Indonesian palm civet coffee. Int. J. Food Sci. 2017, 2017, 6274178. [CrossRef][PubMed] 8. Brehm, A. Musang ( fasciatus). In Brehms Thierleben. Allgemeine Kunde des Thierreichs, Zweiter Band, Erste Abtheilung: Säugethiere, Dritter Band: Hufthiere, Seesäugethiere; Verlag des Bibliographischen Instituts: Leipzig, Germany, 1883; pp. 31–34. Available online: http://www.zeno.org/nid/20007931662 (accessed on 8 June 2021). (In German) 9. Lynn, G.; Rogers, C. Civet Coffee’s Animal Cruelty Secrets; BBC News: London, UK, 2013; Available online: https://www.bbc. com/news/uk-england-london-24034029 (accessed on 8 June 2021). 10. Davies, D. Eat Up—And Don’t Forget the Palate Cleansers; NPR: Washington, DC, USA, 2007; Available online: https://www.npr. org/templates/story/story.php?storyId=11847227 (accessed on 8 June 2021).