In the actual study (linked to in the article) they mentioned testing this out with the coffee or tea powder substituting 1, 2 or 3% of the flour in the recipe. Also note that the used coffee grounds and tea leaves were repeatedly rinsed with distilled water, then dried and made into a powder. So, different than just used grounds or leaves that you would have handy.

Still, this might inspire me to find some existing recipes that call for coffee grounds and tea leaves.

[–] magnetosphere@kbin.social 3 points 1 year ago

Ah, good. I looked right past the link. Thank you for the summary!

[–] Corkyskog@sh.itjust.works 1 points 1 year ago

Powdered more than coffee grind would be hard to achieve... I think the coffee grinder makes the finest powder I can achieve at home.