title_body: Is espresso pre-infusion included in total brew timing?
upvoted_answer: Based in my experience, the "23-28secs" starts counting since you press the button of the water.
  Those 3-4secs of "pre-infusion" that you mention, are part of the whole timing process.
  
  But remember, it will always depends on your set-up (type-of coffee, roast, grind, etc...)
  
  You can measure this empirically watching brewing guides, like:
  
  
  Stumptown Coffee Roasters
  Clive Coffee (includes pre-infusion reference)
  World Barista Champion Event 2015 (livestream.com/worldcoffee)