Caffeine in Coffee: Espresso vs. Cold Brew — Content, Factors, and Safe Limits

Caffeine in coffee is one of the most searched topics online, yet most of what's published is surface-level. I put together a research synthesis combining data from 10+ peer-reviewed studies to compare espresso and cold brew — the two methods with the widest variability. Key findings that surprised me: a single espresso shot can range from 25 mg to 322 mg depending on where it's brewed. A home cold brew can exceed the FDA's 400 mg daily limit in a single glass. Bean species alone accounts for an 80–120% difference in caffeine. The paper covers caffeine by brand, 8 factors per brewing method, a full brewing method comparison, and safe limits by population group. Full article: https://colipsecoffee.com/blogs/coffee/espresso-caffeine