I followed up yesterday’s experiment with a blind testing this morning. I set up two saucepans with the same amount of ground coffee in each. One was over gentle heat while the water boiled while the other was left cold. I then added equal amounts of almost-boiling water before brewing for five minutes. I then asked Jane to bring me a cup from each while I sat in another room with my eyes closed; I instructed her to remember which cup came from which saucepan but not what I was up to.
Unfortunately the “blind” nature of the experiment was slightly destroyed because one cupful was distinctly hotter than the other. I preferred the pre-heated grounds, which had a richer flavour to my taste but Jane leaned towards the other one, which had less fine particles suspended in it. Overall all then, not as conclusive as I wanted although, if making coffee for both of us, it looks like what I was doing is fine!