DrForinor Another query, as a coffee ages - as a general rule - to get a better result from it what seems to work better with grind/ratio? Finer/coarser? Longer/shorter? Or is there no general rule, and go purely on taste?
I don’t tend to buy big bags, nor make lots of brews from one bag via the same method, but if we are talking about the same coffee, that is displaying the same fault in more than one successive cup, change the grind.
For a little context, if you are enjoying a coffee brewed to 18% extraction at 1:2 the concentration of the shot would be around 9%TDS. But a high 22% extraction at 1:3 would be around 7% TDS. So at these intervals in ratio there is no overlap in concentration and therefore, if the strength intensity is OK and you just need to adjust flavour balance, use grind.