baudman wrote:I see them as a triangle, like shutter speed/aperture/ISO in photography.
All three need to be right... but change one and you have to alter one or both of the other two to make up.
I don't see any as any more/less important. And, seeing how you weigh your dose, and so, have practiced tamping accordingly, it's the grind that you play with?
Yeah but no.
The adjustments on your camera are calibrated so that one click of one can be compensated by one click of another. Close your lens by one stop, slow down your shutter by one increment.
I reckon coffee making is relatively robust to changes in dose and tamp, but very sensitive to grind. As you say, change one and you have to alter the other two to make up... but I don't have enough range in my tamp pressure to compensate for any appreciable change in grind.
Dose is (or should be) pretty much fixed. Too much won't fit. Too little doesn't fill the filter properly. Yeah, I have weighed mine in the past to check whether I'm close to ISO standard espresso dose, and I've found that it's pretty hard to deviate too far from standard dose weight (~14g/shot) without finding yourself with an overflowing or half-filled basket. The main reason for my bean-weighing experiments was to work around the known issue my grinder has with hang-up. Grounds get stuck in the chamber and outlet chute, then all fall out at once, sometimes several grams at a time, which is very much the difference between a half-full filter and an overflow that won't even fit in the machine. So I only put in the amount of beans I want to use, and I make sure I get the whole lot out. Playing with scales helped me figure out that a slightly-more-than-level scoop of beans is 14g, although just looking in the basket when the grinder has finished grinding can tell me just as much.
Tamp really makes very little difference, IMO. Once the grounds are compressed firmly in together (so they don't fall out when tipped upside down), pressing them harder doesn't change much. Sure, at the world-series barista championships it might change enough to make a difference, but that's a whole new level of anal retentiveness. For a punter like me, it's either tamped or it's not. Almost an on-off switch. They say 15kg... I reckon anything from about 5kg to 50kg would probably be close enough.
So, a full-but-not-overflowing filter basket, tamped until it's... tamped... ish... that really only leaves
grind as a variable to play with. I don't play with that much either, except that different beans absolutely need a different grind, and as a batch of beans gets older, it needs a progressively (slightly) finer grind. My regular beans need my grinder set to #10 when fresh and #9 when starting to get a little bit stale. Pre-aged
supermarket beans need to be down at #5 or #4.
If I grind my beans at #4 I'll blow the pressure relief valve on my machine. If I grind supermarket beans at #10, I'll get a 30mL shot of watery suds run through in 5 seconds. There's no way I can get that much variation by changing dose or tamp.
In the video, they crapped on far too much about the "flour with sand" texture. Sure, that's a reasonable description of coffee that is fine enough for espresso (as opposed to sawdust grind for a plunger). #4 and #10 grinds are both "flour with sand".
An inexperienced home coffee maker might be convinced by the video that any flour-with-sand ground coffee will do, as long as he follows all the other important steps like wiping the basket dry, running some water through the head before loading, and switching the pump on immediately the PF is loaded (even before putting cups under it). All of which are probably good 1%'ers to get you over the line at the championships... but the grind is the 80%'er, and if you don't get it somewhere close to right, there's no way your coffee will be anywhere close to right.