Brisbane: I own a Vivaldi Mini 2 and will give you a few tips that work well with me. I can't put more than 16 grams in a stock Vivaldi basket because of lack of headroom. The shots get noticeably worse at 17 or 18 grams (for me anyway). Also, I had lots of problems with channeling until I started nutating with the tamper. Now I hardly ever get a spritzer. I use a naked PF. I have a Mazzer SJ. I've tried tamping at 30 lbs as well as much lighter and that didn't seem to have as much an effect as the two above points. Good luck. Michael (BTW, I have the mechanical preinfusion device on mine. Not sure if it made any difference, but I've been too lazy to take it off.)

RapidCoffee wrote:+1 on 2:3 brew ratios. My typical Spaz 53mm double basket dose is ~15g, which produces a shot volume of ~45ml. I generally let the shots run a bit longer (closer to 30s), but that is just personal preference.

John,
I'm now confused, since 15g/to 45ml is about 3X, and not the 1.5ratio that Jim referred to. Per Jim's guidance, 15g should be getting about 22.5ml?

I'm missing something?

Yes: the difference between volume and weight (or mass).

Depending on the amount of crema, 45ml might weigh 22,5g (yielding a 67% brew ratio) or 30g (yielding a 50% brew ratio) or even 45ml (no crema whatsoever, yielding a 33% brew ratio). This spans the range from lungo (33%) through normale (50%) and even ristretto (according to AndyS, 67% falls in the ristretto range). You need to weigh the extracted beverage as a reality check; volume simply won't do the job.

John,
Thanks for the clarification!