Chlorogenic Acids in Coffee: What They Are and Why They Matter
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If you have ever wondered why a dark roast tastes more bitter than a light one, part of the answer is a family of molecules most coffee drinkers have never heard of. Chlorogenic acids in coffee are the main polyphenols in the green bean, making up several percent of its weight. Roasting breaks most of them down, and their breakdown products, especially lactones and phenylindanes, are a big source of coffee’s bitterness. A typical 200 ml cup still delivers roughly 70 to 350 mg of chlorogenic acids, depending on the beans and the roast.
Despite the name, they contain no chlorine: chlorogenic comes from Greek words for green and producing, after a green color seen when the compounds oxidize. Here is what they are, what roasting does to them, and why they matter for both flavor and nutrition research.
Key takeaways
- Chlorogenic acids (CGAs) are esters of quinic acid with caffeic, ferulic or p-coumaric acid; the main one is 5-caffeoylquinic acid.
- Green Arabica contains about 4 to 8.4% CGAs by dry weight; Robusta about 7 to 14.4%.
- Roasting destroys them progressively, up to 95% in very dark roasts, creating bitter lactones and phenylindanes.
- Lighter roasts and Robusta beans generally give a cup with more chlorogenic acids.
- Most CGAs reach the large intestine, where gut bacteria break them down.
In this article
- What are chlorogenic acids?
- Does roasting destroy chlorogenic acid?
- How much is in your cup?
- How chlorogenic acids shape flavor
- What happens in your body
- FAQ
What are chlorogenic acids in coffee?
Chlorogenic acids are a group of related plant compounds formed when quinic acid links up with one or two hydroxycinnamic acids. Coffee is one of the richest dietary sources. In green beans, a 2006 review in the Brazilian Journal of Plant Physiology describes these main classes:
| Class | Example | Approximate share of total CGAs in green coffee |
|---|---|---|
| Caffeoylquinic acids (CQA) | 5-CQA, the classic chlorogenic acid | 5-CQA alone about 56 to 62%; 3-CQA and 4-CQA up to about 10% each |
| Dicaffeoylquinic acids (diCQA) | 3,5-diCQA | About 15 to 20% |
| Feruloylquinic acids (FQA) | 5-FQA | About 5 to 13% |
| p-Coumaroylquinic acids and mixed diesters | 5-p-CoQA | Minor amounts |
Species matters a lot. The same review reports 4 to 8.4% CGAs by dry weight in green Arabica and 7 to 14.4% in green Robusta. That is one reason Robusta tastes harsher and more astringent. If you are curious how the two species compare on other measures, see our Arabica vs Robusta guide.
Does roasting destroy chlorogenic acid?
Yes, progressively. As beans heat up, chlorogenic acids break apart, lose water to form lactones, and react with sugars and amino acids in Maillard and related reactions. According to Farah and Donangelo, CGA losses run at about 8 to 10% for every 1% of dry matter the beans lose during roasting, and very dark roasting can destroy up to 95% of the original content. Commercial roasted coffees end up with roughly 0.5 to 7% CGAs.
| Roast stage | What happens to chlorogenic acids | Effect in the cup |
|---|---|---|
| Green coffee | Highest content, no lactones | Not drinkable as is; extracts taste grassy and astringent |
| Light roast | A large share remains; lactones begin to form after about 6 to 7% weight loss | Brighter acidity, cleaner bitterness |
| Light-medium roast | Lactones peak at around 14% weight loss | Balanced acidity and pleasant bitterness |
| Medium-dark roast | CGAs and lactones decline; breakdown products build up | Fuller body, more roasty bitterness |
| Very dark roast | Up to 95% of CGAs destroyed; phenylindanes accumulate | Lingering, harsh bitterness, smoky notes |
The Maillard reaction plays a big role in this transformation; our article on the Maillard reaction in coffee roasting explains the browning chemistry behind it.
How much is in your cup?
Home brewing extracts most of what is left in the roasted bean, about 80 to 100% of the CGAs and lactones according to the same review. A 200 ml cup contains approximately:
- Arabica: about 70 to 200 mg of chlorogenic acids
- Robusta: about 70 to 350 mg
Daily intakes vary widely: people who avoid coffee may get under 100 mg a day from other foods, while moderate to heavy coffee drinkers can take in roughly 0.1 to 2 g a day.
A worked example
Say you drink three 200 ml cups of a medium-roast Arabica a day. Using the review’s range, that is somewhere between 3 x 70 = 210 mg and 3 x 200 = 600 mg of chlorogenic acids. Switch to a very dark roast and you would sit near the bottom of that range; switch to a light roast or add Robusta and you would move toward the top.
How chlorogenic acids shape flavor
Chlorogenic acids themselves contribute acidity and astringency, the slightly drying feel on the tongue. The more striking story is what they become. In 2007, food chemists led by Thomas Hofmann at the Technical University of Munich reported that coffee’s bitterness comes largely from chlorogenic acid breakdown products that do not exist in green beans:
- Chlorogenic acid lactones dominate bitterness in light to medium roasts.
- Phenylindanes, formed when lactones break down further, build up in dark roasts and espresso and give a harsher, longer-lasting bitterness.
The same research put caffeine’s share of perceived bitterness at only about 15%. That is why decaf can still taste quite bitter, and why our article on why coffee tastes bitter focuses on roast and extraction more than caffeine.
Practical brewing tips
- Want a softer, less lingering bitterness? Choose a light or medium roast and avoid over-extraction.
- Love a bold, roasty cup? Dark roasts deliver exactly the phenylindane bite many espresso drinkers enjoy; pair them with milk to round it off.
- Find light roasts too sharp? A medium roast keeps some brightness while softening astringency.
If you want to taste the difference yourself, brew a lighter coffee such as our Blonde, a light, caramel-sweet blend from Central America and Africa, next to our Italian Roast, our darkest, smoky blend of Arabica and Robusta. For a Robusta-forward cup, try our Robusta from West Java, full-bodied with cacao, Brazil nut and malt notes. Our blends cover the rest of the roast spectrum, and every bag is roasted 1 to 5 days before delivery.
What happens in your body
Only part of the chlorogenic acid you drink is absorbed in the small intestine. In a 2010 study of volunteers with an ileostomy, published in Archives of Biochemistry and Biophysics, about 71% of the chlorogenic acids and their metabolites from a cup of coffee were recovered in fluid that would normally pass into the colon. In people with an intact colon, gut bacteria transform much of this into smaller phenolic compounds that are then absorbed.
Chlorogenic acids have strong antioxidant activity in laboratory tests, and they are studied as one of several coffee compounds that may help explain associations between coffee drinking and health outcomes in observational research. Those associations do not prove cause and effect, and coffee contains hundreds of other active compounds, so no single health effect can be credited to chlorogenic acids alone. Concentrated green coffee extract supplements are a separate product from brewed coffee; if you are considering one, talk to your doctor or pharmacist first.
Chlorogenic acid FAQ
Is chlorogenic acid the same as caffeine?
No. They are different molecules. Chlorogenic acids are polyphenols; caffeine is an alkaloid. Decaf coffee still contains chlorogenic acids.
Does light roast coffee have more chlorogenic acid?
Yes. Roasting breaks chlorogenic acids down, so lighter roasts retain more than dark roasts.
Does instant coffee contain chlorogenic acids?
Yes. Instant coffee is made from brewed coffee, so it also contains chlorogenic acids; amounts vary by product and roast.
Do chlorogenic acids make coffee acidic?
They contribute to coffee’s acidity and astringency, along with other acids. Our article on whether coffee is acidic explains pH and perceived acidity.
Why is it called chlorogenic acid if it has no chlorine?
The name comes from the Greek for green and producing, after the green color that appears when the compounds oxidize, not from chlorine.
Sources
- Farah A. and Donangelo C.M., Phenolic compounds in coffee, Brazilian Journal of Plant Physiology, 2006
- Report on Thomas Hofmann’s coffee bitterness research presented at the American Chemical Society meeting, ScienceDaily, 2007
- Stalmach A. et al., Bioavailability of chlorogenic acids following acute ingestion of coffee by humans with an ileostomy, Archives of Biochemistry and Biophysics, 2010
Facts checked in October 2026.
This article is for general information only and is not medical advice. If you have a health condition, are pregnant or take medication, ask your doctor before changing your caffeine intake.
Keep reading: Why does coffee taste bitter? · Light vs medium vs dark roast · Shop blends