Caffeine content of decaffeinated coffee
R. R. McCusker, B. A. Goldberger, E. J. Cone · Journal of Analytical Toxicology 30(8):611 · 2006 · academic.oup.com
The only widely cited direct measurement of caffeine in retail decaf. Ten outlets were sampled; decaffeinated brewed coffee measured 0–13.9 mg per 16 oz serving, and decaf espresso 3.0–15.8 mg per shot. It establishes that decaf is low-caffeine rather than caffeine-free, and that the variation between outlets is large enough to matter to anyone counting.
How much weight this carries
Well established. Safe to rely on as stated.
What it says
- Brewed decaf measured 0–13.9 mg caffeine per 16 oz serving — Across ten commercial outlets sampled in the United States.
- Decaf espresso measured 3.0–15.8 mg per shot
- Variation between outlets exceeded variation within an outlet — Which means the brand you buy matters more than the cup-to-cup luck of the draw.
What it does not say
- It does not establish a safe threshold for caffeine-sensitive people, or for pregnancy. It measured what was in the cup, nothing more.
- It is a US sample from 2006. It is not evidence about what a European specialty roaster is selling in 2026, and it should not be cited as if it were.
- It does not compare decaffeination processes. Outlet identity was recorded; process was not.
Recorded because the errors in this subject all point one way: toward claims more confident and more flattering to decaf than the evidence supports.
Limitations
Small sample, single country, nearly twenty years old. It remains the most cited figure because nobody has repeated it at scale — which is itself worth knowing.
The figure most often quoted about decaf — that a cup carries “2 to 15 mg” — traces back through the FDA to work of this kind. This paper is the measured version, and it is worth citing directly rather than at second hand, because the range it reports is wider at the top end than the number usually repeated.
Cited on
Related sources
- Spilling the Beans: how much caffeine is too much Regulatory guidance · US Food and Drug Administration
- Directive 1999/4/EC relating to coffee extracts and chicory extracts Regulatory guidance · European Parliament and Council
- Swiss Water — decaffeination process and caffeine content Industry source · Swiss Water Decaffeinated Coffee Inc.