brewedshot.com

Espresso extraction engineering

Contents

Topic

Diagnostics

Symptom to mechanism to remedy, with each branch justified rather than asserted.

Scope

Channelling, clogging, shots that will not repeat, gauge and scale readings that disagree with the cup, and how to tell one failure mode from another before changing anything.

Articles (4)

  1. La Marzocco’s open-group flow test targets differ by region

    Side-by-side reading of La Marzocco’s UK and US Home flow-rate test pages shows they assign different model sets to the same ~250 g / 30 s and ~500 g / 30 s open-group targets, while both define the test as a restrictor-occlusion check on…

  2. Rocket’s right-hand gauge is printed as pump pressure and as service-boiler pressure

    Rocket Espresso’s English instruction manual examined here (InDesign/PDF dated 31 March 2019) assigns the right-hand gauge three incompatible kinds of claim in one file — “on all machines” pump pressure; a mains-install blind-filter check…

  3. Strada AV’s heat-up expansion ceiling is printed as 13 bar and as 11–12 bar

    La Marzocco’s Strada AV operating manual examined here (MAN.16.1.02 EN V2.0) gives the coffee-boiler heat-up expansion-valve check two different ceilings in one file — never exceed 13 bar in the procedure, then 11–12 bar / adjust above 12…

  4. Synesso MVP’s brew gauge “normal” spans three conditions

    Synesso MVP & MVP Hydra Technical Manual Version 2020.1 examined here prints three different “normal” bands for the same brew-pressure gauge — line ~3–5 bar, brew 9 bar (with 8.5–9 and 8–9.5 variants in fault text), and heat-expansion…