Caffeine, training and sleep
How long caffeine stays in your body, and how to time your cup.
Last reviewed 7 Nov 2026
Science
Coffee science
Short summaries of the research behind our coffee, each with its sources.
Roasting and CGA
Why a lighter roast keeps more of the bean's chlorogenic acids.
Last reviewed 7 Nov 2026
Paper filters and coffee oils
Why we recommend pour-over with a paper filter.
Last reviewed 7 Nov 2026
Robusta vs Arabica
How their caffeine compares, and why Performance+ needs fewer beans.
Last reviewed 7 Nov 2026
How we estimate caffeine and CGA
Where the calculator's figures come from, in plain words.
Last reviewed 7 Nov 2026
Research changes. These summaries reflect the studies available on the date shown, and we update them as new evidence appears. They are general information, not medical advice.
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