sbrussell wrote: I'm making a lot os 7-8 g singles and unless I use a low brew ratio, there's almost nothing in the cup.
Typical Italian brew ratios are higher, i.e more ristetto, than most anything here, at least that's been true for every time I've been there.
First off, the INEI definitions are for volume, which is about twice the weight when crema is included. Second, most people in Italy would be horrified to get a shot with 25 mL volume unless it was made by somebody very skilled (all the machine sellers and roasters tell non-baristas pulling at restaurants, hotels, trains, etc, to grind real fine and pull ristretto).
The one really non-negotiable espresso expectation in Italy, as it should be everywhere, is for a mouth coating, oily-creamy shot. The way to make this easier is to pull more ristretto, and/or use Robusta. Therefore, the par is a shot that ranges from a few drops to a small pool at the bottom of the cup. It takes real skills to get oily, creamy and mouthcoating single shots that are a full 25 mL long and don't use Robusta.
Also, as a technical matter, the INEI temperature is taken by putting a TC up the PF spout and measuring the highest temperature attained, towards the end of the shot; it runs about 5C cooler than measuring at the top of the puck.