Exercise 1 - solution

The INEI reference shot: 7 +/- 0.5 g of ground coffee, water at 9 +/- 1 bar, running for 25 +/- 5 seconds, giving 25 +/- 2.5 ml in the cup including crema.

Reasons for caution (any two):
- The INEI temperature (88 +/- 2 C at the unit) does not match the 91-95 C quoted in chapter 6, and nothing in the sources reconciles them.
- Pressure figures differ between sources and machine types (9 +/- 1 bar standard, 8-10 bar for spring piston machines, 8-18 bar in chapter 6).
- Several machine-article sections are flagged on the page as needing more citations.