nosiesta I have seen that video - Barista Hustle has a lot of insightful information.
I don’t think it’s so much about diminishing returns though, as I am assuming - perhaps incorrectly - that there should be a place where the acidity/brightness does not seem unbalanced.
Now again, taste is subjective and words are difficult, so when BH uses “heavy, sugary sweet, crisp and vibrant acidity” as the taste, that has a number of mixed messages for me, and how I interpret things.
I guess, overall, the intention is to learn how to differentiate between under-extracted / sweet-spot / over-extracted so you can get the best cup out. Learning the difference between over and under is therefore critical because the best bit is in-between those, and it should be easy to find both ends and then bring it back to the middle (ish).
However, taking MWJB’s notes as well, it’s clear that determining which level of extraction you’re at is perhaps also not that clear cut, and what is perceived as over-extraction may not be that (unless I’m misreading).
All of this helps - it brings additional insight into the process and the journey by which experience is gained. The ‘trick’ is for each person to find how best to apply such knowledge to their own practice.
… or maybe I just start drinking milk drinks instead, and don’t worry so much as they will cover the majority of the differences I notice in my espressos 😅