Sitting longer than about 2 minutes in a French press didn’t extract more caffeine, surprisingly.
Dark roast had higher caffeine per ounce, but not a huge difference.
Instant coffee had less caffeine than expected.
Timestamps:
0:00 Intro
0:53 How the analyser works
2:39 Test 1 Filter vs. Espresso
3:59 Test 2 Cumulative Extraction
7:53 Test 3 Contact / Steep Time
9:17 Test 4 Instant Coffee
13:28 Test 5 Light vs Dark roast
16:42 A Note On Caffeine Variance in Different Coffees
18:09 Wrap Up
Related videos:
Caffeine Explained: https://youtu.be/j805qJJajmM
Wired Coffee Support: https://youtu.be/pjJqOgFyCxI