In decaffeinated coffee, caffeine extraction can occur using chemical solvents (one of which is probably carcinogenic) or with the 'natural' method using water and carbon dioxide.
Both versions are widespread in the Italian market, as shown by our analysis of private labels, discount, and private industry brands on 20 decaffeinated coffees: 13 ground decaffeinated coffees for moka, including one organic, and 7 instant.
Decaffeinated coffee, the 'anti-stress' alternative
Decaffeinated coffee is the perfect substitute for 'regular' coffee for those who tend to drink more than 3-4 cups of coffee a day or must abstain on doctor's advice.
Beneficial for the nervous system in healthy adults (1), coffee causes increased stress levels if consumed excessively. (2)
Caffeine extraction
The denomination of decaffeinated coffee requires a reduction of the naturally present caffeine to a level not exceeding
- 0.10% in roasted coffee,
- 0.30% in instant coffee. (3)
The reduction is significant. In the most consumed blends in Italy, caffeine amounts to
- 1.2-1.5% for arabica,
- 2-4% for robusta.
Extraction with solvent or with water
Caffeine extraction from green coffee, it occurs through a treatment with water and steam to swell the beans followed by the use of a substance that extracts the caffeine.
The authorized substances There are four as solvents.
1) Water
The extraction Caffeine extraction by immersing the beans in water is the most natural but also complicated method. In fact, along with caffeine, many coffee aromas are also extracted. This can be remedied by saturating the water with other coffee aromas or by extracting the caffeine (even using solvents) from the resulting water to then reintroduce them into the coffee.
2) Ethyl acetate
Ethyl acetate is also naturally present in fruit, but in industry the synthetic version is used. It is effective as a solvent, extracting only caffeine, but it is rarely used because it leaves a fruity aroma and is highly flammable.
In coffee a residue of 20 mg/kg is allowed. (7)
3) Supercritical carbon dioxide
Carbon dioxide, subjected to a minimum pressure of 72 bar and a temperature of 31°C, assumes properties intermediate between those of a liquid and those of a gas, allowing multiple uses. Due to its chemical characteristics, this fluid is comparable to an organic solvent, very similar to lipophilic substances.
The technique is used for the removal of caffeine from coffee (since 1991), but also for extracting the bitter component from hops for the brewing industry, treating cork to reduce the possible 'cork taint' defect in wines, and for extracting CBD from Cannabis Sativa L. (4,5)
4) Dichloromethane, a probably carcinogenic solvent
Dichloromethane (or methylene chloride) is the solvent traditionally used for caffeine extraction. It is added to the water tank in which the green coffee is immersed and then removed by evaporation. It is effective in removing only the caffeine while preserving the organoleptic profile of the coffee.
The negative aspect of this solvent is its toxicity. The International Agency for Research on Cancer (IARC) has classified it in category 2A, meaning 'probably carcinogenic to humans'. (6)
Two elements should mitigate the risks of environmental pollution and human exposure to the substance through the consumption of decaffeinated coffee using dichloromethane:
– the solvent is recovered at the end of the cycle and reintroduced into production,
– dichloromethane evaporates at 40 °C, therefore it is considered essentially absent in the finished product (roasting takes place at about 200 °C).
In roasted coffee a residue not exceeding two parts per million (ppm), i.e., 2 mg/kg, is allowed. (7)
4.1) The battle in the United States against dichloromethane
In the United States the organization CSPI (Center for Science in the Public Interest) and other consumer groups have been requesting since March 2024 that the FDA (Food and Drug Administration) ban the use of dichloromethane in food productions.
The United States Agency for environmental protection (EPA, Environmental Protection Agency), in fact, has decided the gradual elimination of dichloromethane, starting from July 2024, in non-food industrial uses, precisely because of the carcinogenic risk to humans. (8,9) Food uses therefore remain without precautionary measures.
Decaffeinated coffee in Italy, with and without solvent
The classification as a probable carcinogen for humans meanwhile pushes the coffee industry to replace dichloromethane with more expensive solvents such as carbon dioxide and water.
Organic decaffeinated coffee is the exception. In this case, the only authorized method for extracting caffeine is the natural one.
7 out of 12 'natural'
Of the 20 coffees decaffeinated for moka examined, seven are presented as obtained by 'natural' method. Among these is the only organic product.
The remaining six lack indication on the type of solvent used. As usual, in the absence of mandatory indications on the method used to extract caffeine, only voluntary declarations on the label help distinguish. It is inferred that extraction is done using chemical solvent.
Instant decaffeinated, only one is 'natural'
As many as 6 of the 7 soluble decaffeinated coffees have no indications on the method used to extract caffeine.
The only soluble decaffeinated coffee explicitly obtained by the ‘natural’ method is from Nescafé.
Marta Strinati
Cover image, Couleur by Pixabay
Notes
(1) Dario Dongo, Andrea Adelmo Della Penna. Coffee can protect the nervous system. Food Times. 22.8.21
(2) Marta Strinati. The effects of habitual coffee consumption on brain activity. Food Times. 10.3.22
(3) Ministerial decree May 20, 1976, published in the Official Gazette no. 153 of June 11, 1976 and subsequent amendments https://www.normattiva.it/eli/id/1991/03/19/091G0122/ORIGINAL
(4) Deborha Decorti. Cold pasteurization and supercritical CO2. Food Times. 26.3.19
(5) DM January 23, 1991, no. 87. Regulation amending the ministerial decree of May 20, 1976, concerning the production and trade of decaffeinated coffee. https://www.normattiva.it/eli/id/1991/03/19/091G0122/ORIGINAL#:~:text=%C3%88%20consentita%20la%20decaffeinizzazione%20del,pubblicato%20nella%20Gazzetta%20Ufficiale%20n.
(6) IARC (2017), pp . 177-255
(7) DECREE August 4, 2011, no. 158. Regulation implementing Directive 2010/59/EU of the Commission of August 26, 2010, which amends Directive 2009/32/EC of the European Parliament and of the Council for the approximation of the laws of Member States concerning extraction solvents used in the preparation of food products and their ingredients. (11G0200) (Official Gazette General Series no. 225 of 27-09-2011) https://www.gazzettaufficiale.it/eli/id/2011/09/27/011G0200/sg#:~:text=%2D%20La%20direttiva%202009%2F32%2F,e’%20stata%20pubblicata%20nella%20G.U.U.E.
(8) Zachary Goldstein. EPA banned methylene chloride, but it’s still used in foods. CSPI 23.5.24 https://www.cspinet.org/cspi-news/epa-banned-methylene-chloride-its-still-used-foods
(9) National Toxicology Program, Department of Health and Human Services. Report on Carcinogens, Fifteenth Edition. Dichloromethane https://ntp.niehs.nih.gov/sites/default/files/ntp/roc/content/profiles/dichloromethane.pdf
Professional journalist since January 1995, she has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and magazines (NumeroUno, Il Salvagente). Author of journalistic investigations on food, she published the volume 'Reading the labels to know what we eat'.
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