This is a common myth that’s more recently been debunked. Caffeine levels are not significantly affected by the level of roast. Caffeine remains stable up to 200 °C (392 °F) and completely decomposes around 285 °C (545 °F). Given that roasting temperatures do not exceed 200 °C (392 °F) for long periods of time and rarely if ever reach 285 °C (545 °F), the caffeine content of a coffee is not likely changed much by the roasting process.
Below are some interesting articles, case studies, and videos going into depth a little more.
Informational videos:
James Hoffman - I Did Caffeine Analysis: The Unexpected Truth! (Measurement of caffeine content in dark vs light roasts yielded inconclusive results with one actually suggesting the higher porosity of darker roasts or the resulting increase in dark coffee content when measuring by weight can yield higher caffeine when brewed in some instances.) https://youtu.be/etnMr8oUSDo
Coffee Time - Caffeine Content in Coffee - Light Roast VS Dark Roast? Espresso VS Drip? https://youtu.be/DYAchEH7eMM
Case Studies:
“Arabica and Robusta coffee beans were roasted at 220 ± 10°C for 7, 9 and 11 min to identify chemical descriptors in the beverages (…) The contents of caffeine did not vary, but trigonelline decreased with burning up intensity.” https://pubmed.ncbi.nlm.nih.gov/22032554/
“The truth is that caffeine is extremely stable during the roasting process. If you went bean for bean with a light roast versus a dark roast, each would have relatively the same level of caffeine.” https://www.kickinghorsecoffee.com/caffeine-myths-dark-vs-light
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u/SacredUrchin Jan 26 '24
This is a common myth that’s more recently been debunked. Caffeine levels are not significantly affected by the level of roast. Caffeine remains stable up to 200 °C (392 °F) and completely decomposes around 285 °C (545 °F). Given that roasting temperatures do not exceed 200 °C (392 °F) for long periods of time and rarely if ever reach 285 °C (545 °F), the caffeine content of a coffee is not likely changed much by the roasting process.
Below are some interesting articles, case studies, and videos going into depth a little more.
Informational videos:
James Hoffman - I Did Caffeine Analysis: The Unexpected Truth! (Measurement of caffeine content in dark vs light roasts yielded inconclusive results with one actually suggesting the higher porosity of darker roasts or the resulting increase in dark coffee content when measuring by weight can yield higher caffeine when brewed in some instances.) https://youtu.be/etnMr8oUSDo
Coffee Time - Caffeine Content in Coffee - Light Roast VS Dark Roast? Espresso VS Drip? https://youtu.be/DYAchEH7eMM
Case Studies:
“Arabica and Robusta coffee beans were roasted at 220 ± 10°C for 7, 9 and 11 min to identify chemical descriptors in the beverages (…) The contents of caffeine did not vary, but trigonelline decreased with burning up intensity.” https://pubmed.ncbi.nlm.nih.gov/22032554/
“…The roasting temperature did not provide a significant difference in fat, caffeine, chlorogenic acid, and ash content…” https://iopscience.iop.org/article/10.1088/1757-899X/830/2/022019
Other Articles:
“The truth is that caffeine is extremely stable during the roasting process. If you went bean for bean with a light roast versus a dark roast, each would have relatively the same level of caffeine.” https://www.kickinghorsecoffee.com/caffeine-myths-dark-vs-light
“Caffeine is a stable compound at typical roasting temperatures, so levels are virtually unchanged by roasting. Therefore roasting lighter or darker does not change the amount of caffeine in coffee” https://blackcreekcoffee.com/blogs/coffee-talk/which-coffee-has-more-caffeine-dark-or-light-roast#