EddieMoonshine I don’t even really know what my point is but it just struck me a rather comical how the coffee community generally obsesses over microns of grind sizes and slight taste changes but blends never get a mention. I get that roast levels may play a part because if I were to burn ( dark roast) a slice of hovis, Warburton’s and kings mill then they would all taste the same but a normal toast (medium -light) would all taste very different to each other.
Microns are just the most practical measurement for bean particles, obsessing over them or not, that’s just the reality. Hundredths of a mm would probably be enough for a given brew method/grinder, but measurement tools are normally calibrated to micron resolution. Of course, if you want to use thousandths, or ten thousandths of an inch, then knock yourself out :-)
Even using the same grind size, the same beans, there are usually differences from one cup to the next, because we are brewing tiny amounts and therre is always natural variance. After a point, natural variance slips into generic & easily identified (& fixed) brewing malfunctions. Identifying & correcting these is the point of measurement & control, not so much to nail identical taste cup to cup.
Roast level is a preference, dark roasts can be less objectionable when under-extracted, as opposed to tart/sharp light/medium espresso, but roast level does not offer a silver bullet regarding typical malfunctions.
Blend and origin are also a preference - I measure most of my brews, but it’s pretty clear to me that certain origins (Colombia, Rwanda, Kenya) are much more likely to meet my preference, compared to some others (though I have had the odd really good bag from most origins, talking here about the game of averages). No way to really fix that other than buy what you suspect you will like, to start with.
