Another interesting video
I was doing this years ago. Obviously without the knowledge that this chap has but I often pulled "the sweet shot’. If we assume a 30 second pour on a lever machine, capture the first 5 seconds, in a separate cup the next 20 and the final 5 in the first cup. The beans were Java Jampit and the machine an L1 and the grinder I am guessing at a Mythos or a Ceado E92S.
Systemic visited me one day and he drank something like 8 sweet spot shots and was really wired! It is a fun experiment to do