Square mile gives specific espresso recipes for its beans (or at least the espresso roasts) and seems to change ratio as well as time and dose per bean, although does come with caveat that its how their machine tasted best, although at least I recall them telling you what that was.
actually, just found it for Red Brick
RECIPE:
We recommend the following recipe as a starting point:
Dose: 19 grams
Brew temperature: 201ºF-202ºF/94ºC-94.5ºC
Brew time: 28-32 sec
Brew Ratio: 1:2
Brew weight: 38 grams
This profile and recipe was developed on a Victoria Arduino VA388 Black Eagle with VST 20g baskets – so should be taken as a starting point, and not an absolute as different machines extract in different ways.
The recommended baskets for this espresso recipe are the VST 20g.
whilst the decaf is
RECIPE:
We recommend the following recipe as a starting point:
Dose: 19 grams
Brew temperature: 201F-202F/94C-94.5
Brew time: 28-30 sec
Total Volume: approx 50ml
Brew weight: 38 grams