Video:

Pour over brewing Vs Expresso

Pour over 170mg

Expresso 110mg

Extending the extraction time appears to be a big factor in the amount of caffeine extracted.

Instant Coffee 40 - 60 mg

Roast level

Light 67.5mg

Dark 72mg

it may be that the dark roasted coffee is less dense and allows better extraction of caffeine.

Espresso coniesuers will cry 😭😭😢😭😭

Anyway, extending the extraction time of the Espresso will greatly increase the caffeine extracted. It's SCIENCE!

I use the Aeropress every morning. Wife likes Taster's Choice instant.

Those are things he plans to test, but in the video he postulates, in so many words, extending the extraction time appears to be a big factor in the amount of caffeine extracted, probably a key factor.

has he tried running the brewed coffee through the used grounds a second time and then measuring caffeine content?

whatever...even though caffeine is part of the reason I enjoy coffee, it isn't the only thing...taste matters...

Not in this video.

Percolator coffee, multiple passes through the grounds.

He actually touched a bit on the Aeropress around the 8min mark, when he took a look at the effect of steep time.

I don't remember the last time I saw a perculator, other than the old one I use on my camping stove.