Chlorogenic acid
Major antioxidant in green coffee (5-12% dry weight), partly degraded during roasting. Precursor of acidity and caramel aromas.
Why do chlorogenic acids matter in specialty coffee?
Chlorogenic acids (CGAs) are a family of ester compounds formed from hydroxycinnamic acids (primarily caffeic acid) and quinic acid. They are the most abundant polyphenols in coffee, comprising 6-10% of green coffee dry weight in Arabica and up to 14% in Robusta, and one of the primary sources of coffee's antioxidant activity. During roasting, CGAs undergo complex thermal degradation: they break down into caffeic acid, quinic acid, and lactone derivatives (chlorogenic acid lactones). At higher roast temperatures, these lactones further degrade into bitter phenylindane compounds, which are significant contributors to the harsh bitterness of dark roasted coffee. The health significance of CGAs has been the subject of considerable research: multiple epidemiological studies (including the Harvard T.H. Chan School of Public Health cohort studies) associate regular coffee consumption (including CGA intake) with reduced risk of type 2 diabetes, liver disease, and cardiovascular events. Light roasted coffees retain significantly more CGAs than dark roasts, which may partially explain their different health profiles. A 200ml cup of light roast filter coffee contains approximately 150-250mg of CGAs; the same volume of dark roast contains 50-100mg.
How do chlorogenic acids affect your cup?
For health-conscious coffee drinkers, light roast filter coffee maximises CGA intake compared to dark roast or espresso (which uses smaller volumes). Unfiltered coffee (French press) retains more diterpenes (cafestol, kahweol, with independent effects on LDL cholesterol) but similar or slightly lower CGAs than filtered. The antioxidant marketing of coffee products should be viewed critically, the bioavailability of coffee CGAs in the human gut is approximately 15-25%, meaning absorbed dose is a fraction of consumed dose.
Related Terms
Related terms: Coffee polyphenols, the broader family including CGAs. Maillard reaction, occurs alongside CGA degradation during roasting. Bitterness, CGA degradation products (phenylindanes) contribute. Light roast, highest CGA retention.