When looking at the various recipes out there, I often wonder how much of this is just AeroPress superstition, and how much of it actually matters. For example, wetting the filter, pre-heating the gear and all the different stirring styles. Seems like those things could produce a different result, but I’m not experienced enough to taste the difference. Therefore, I just do what makes sense from the perspective of chemistry.
Finer particle size increases the surface area, which in turn, speeds up the extraction.
Higher temperature speeds just about everything in chemistry, so I guess it should apply to solid-liquid extraction too.
Relying on diffusion to take care of transportation is painfully slow. The concentration gradients take forever to spread even a few centimeters, so stirring speeds things up a lot. I mean, there’s a reason why most lab scale and industrial scale reactors come with a mixer.
Adjust the extraction time based on variables 1, 2 and 3.
As a side note, concentration difference matters too. Using previously made coffee to extract more soluble materials into it, is obviously going to be a lot slower than using clean water. This is why a pour over makes a lot of sense, as far as extraction yield is concerned. Incidentally, you can adapt the AP for that as well, but then you would need to balance between grind size clogging up the filter. Generally not worth it IMO, but it is an interesting experiment. It could be worth it if all you have is an AP, but you need to make coffee for a larger audience.