coffee.me wrote:But how come nobody says:
"my grinder doesn't do 18g well", and instead they say:
"my machine doesn't like to be updosed"? I dunno, this confirmation opens the door for so many questions* that I'm starting to think we're not talking about the same thing. Really? Narrow sweet spots?

I frequently find a dose suffers a meltdown and requires a drastic change, even though the identical dose on a similar coffee was delish. An e61 is very tolerant of overdosing, but sometimes I have to go from 9 to 7.5g or 12g to stop the meltdowns. Some coffees don't care anywhere from 8 to 9, whereas some are very fussy about 8.5±0.2g. I may have to adjust the temperature from 202° to 198° or ???. It's a continuum and it's impossible to adjust one thing in isolation.
coffee.me wrote:So far I'm getting "yes, grinders have sweet spots". I know that's what I hoped to hear; but it also is a confirmation that my Versalab's 15g doubles will never be amazing -- sad, really.
Why would anyone care? If it's a 15g double and nothing else, buy a coffee and a machine that gives amazing shots at those parameter. Don't be surprised if everything else goes pear shaped.
One of my favorite bar coffees is 20g triple ground on a Robur-E pulled on a Synesso to 60ml @ 202.5°F. If I try anything like that, it's hopeless. Around 8g @ 198.5°F on the MC4 and HX to about 20ml results in an equally delicious, and very similar tasting, shot.
Entirely too much rote and unwillingness to experiment pervades the espresso culture. How many times have we read "I kept the dose @ [the mythical number of grams]..." as someone wails about their meltdowns

If a good shot can't be had from 7-12 or 12-20g, "It's the coffee, stupid"
"Sciences may be learned by rote, but wisdom not."
Laurence Sterne