Coffee and health – Are the oils in coffee dangerous?

Dany Marquis

As we are serious and whole-grain people, I will skip the preamble and preliminary of this section to get straight to the serious stuff.

I thank Dr Jacques Lévesques and Dr Olivier Ouellet for bombarding me with scientific terms which required hours of reading and for sending documents which surprised me with their ability to promote the natural peristalsis of my digestive tract. . But as the quest for knowledge and truth is not without suffering and sacrifice, I am sincerely grateful for your contribution. Thank you gentlemen!

That being said, you will find in this first text of a series of three, the answer to the following question:

Are the oils in coffee dangerous?

Coffee oils

Beyond their organoleptic property, and the fact that coffee includes 850 identified volatile aromatic components, the consumption of coffee involves the ingestion of the product, containing a real chemical cocktail, including a plant hydrocarbon called terpene. We are rather familiar with mineral-type hydrocarbons which are the origin of oil and natural gas but which have a chemical structure similar to the plant type, composed of carbon and hydrogen molecules.

The plant kingdom therefore produces very specific hydrocarbons, terpenes.

Coffee is basically a plant product, made from the fruit of a shrub, which, after a chemical transformation process called roasting, synthesizes aromatic molecules. These molecules have the main characteristic of being odorous. These are the components that are extracted to make what we call essential oils from plants.

Two types of organic molecules from the terpene family are found in coffee, diterpenes called cafestol and kawehol.

They are found exclusively in the coffee plant and particularly in the beans of its fruits.

In the coffee bean their concentration is of the order of 2 to 13 grams per kilogram of dry beans depending on the species of coffee tree or the variety considered. There is more in Arabica that in the robusta .

Since cafestol is stopped by paper filters, coffee-based drinks whose preparation goes through a filtration stage on a paper filter hardly contain any anymore.

Therefore, coffee drinkers are exposed to cafestol if they use unfiltered preparation methods and the amount of cafestol and kawehol is directly related to the preparation.

Brewing and contact with hot water releases the terpenes from the ground coffee and transfers them to the solvent, water.

The terpene concentration according to the preparation method without filtration:

-          Scandinavian (cafestol: 7.2 mg/cup [cup = 150 mL]; kahweol: 7.2 mg/cup)

-          Turkish (cafestol: 5.3 mg/cup; kahweol: 5.4 mg/cup)

-          French press (piston) has an average cafestol content of 3.5 mg/cup and kahweol of 4.4 mg/cup

-          espresso 1 mg/cup of each diterpene

Regular and decaffeinated coffees contain the same amount of diterpene.

Regular coffee: average of 486 mg/100 g (0.486%) cafestol and 469 mg/100 g (0.469%) kahweol

Decaffeinated coffee: average of 485 mg and 411 mg per 100 g (0.485% and 0.411%), respectively.

There is also a relationship between diterpene content and arabica subspecies.

The IPR 100 and 106 type varieties demonstrate a higher level of Kawehol while those of the Catuai and Icatu varieties have average cafestol ranging from 325 to 604 mg/100 g for green coffee (1.8 times higher) than with IPR varieties.

However, the total diterpene (cafestol + kawehol) is approximately the same among the different varieties.


We can note an increase between the content of cafestol and kahweol for roasted coffee. This is especially what interests us since drinking or eating green coffee is not an option. But we find an increase from 3 to 36% for cafestol and 5 to 47% for kahweol. This relative increase can be attributed to the chemical transformation of the bean during roasting. In the documents reviewed, there is disagreement between the stability of the diterpene level and the roasting process. The pyrolysis occurring in the roasting process also has no major impact on the diterpene content but some authors mention that a certain reduction (low percentage) of terpenes can occur during intense roasting (loss weight of 26.5%, exceeded the 2nd crack), but we must consider the transformation of terpenes into dehydrocafestol and dehydrokawehol as being a reduction. And according to several authors, 1 mg of cafestol and 1 mg of dehydrocafestol have similar effects. We can therefore say that the roasting level has no influence on the diterpene content.

Finally, yes, the oils contained in coffee can be dangerous. The preparation method is the main criterion influencing the contents present in the cup and the roast level has a negligible effect on its contents.

A certain interest from the scientific community has been shown in cafestol and kawehol in coffee since it was realized that it had an impact on the rate of cholesterol in the blood, mainly for cafestol. Around six cups or more of coffee per day would therefore increase cholesterol and the LDL fraction (bad cholesterol or Low Density Lipids). However, some studies show that the coffee-cholesterol-heart disease relationship is not directly linked.

So, if you have problems with this aspect of your health, it is strongly suggested that you drink coffee from a filtered brewing method and drink a little less than 6 per day.

Your doctor remains the supreme reference, I still suggest 2 coffees per day, this should satisfy your addiction while not jeopardizing the business of your favorite roaster. ;-)


Reference :

For more details, I invite you to read the documents below.

Cafestol and Kahweol, Review of Toxicological Literature

Analysis of diterpens in coffee


  • Ben

    très intéressant, merci

  • Antiao Pierre-Jacques

    Superbe article, beaucoup d’humour, comme d’habitude. Je me pencherai un peu plus sur les articles que tu mets en lien. Si tu en as d’autres en stock, je suis preneur ;)
    Merci en tout cas

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