title_body: What skills/techniques are necessary for making espresso?
upvoted_answer: If the concern is solely production of great espresso, I would argue that the 'skillset' required actually consists of a single point.
  
  
  Palate. Being able to discern flavours and work out what is good and bad about any shot is essential in being able to improve your espresso.
  
  
  This is a skill that you'll need to train and perfect but is the only necessary ability in making good espresso.
  
  The real bulk of what makes espresso great is simply being able to control the factors and variables in making it which requires an ability to taste what is wrong with any given shot. I wouldn't say the specific factors that contribute to good espresso are skills (as skills are traits of the barista), but are simply parameters that is up to you to modify and control.
  
  The parameters you need to keep in mind when making espresso are:
  
  
  Freshness of coffee
  Grind size of coffee particle
  Water quality and composition
  Brew temperature
  Brew pressure
  Coffee distribution in portafilter
  Amount of coffee used per shot
  Length of shot/Amount of water pulled/Final output volume
  
  
  Tamp level and pressure are things that affect the shot but aren't exactly variables you would change. These would just be things you would aim to get 'right' every time. 'Right' here means ensuring a level, horizontal bed of coffee and a consistent tamp pressure. Tamp pressure is easier to normalise than it sounds; tamp until the coffee bed stops compressing.
  
  Many of the above will be down to the grinder and espresso machines chosen.
  
  Having a bottomless portafilter enables a clear view of the exit of the shot which serves as an invaluable tool in recognising uneven extractions.
  
  Tips:
  
  
  Never tap/knock the portafilter after tamping. This completely destroys puck uniformity.
  Use a distribution tool to help evenly distribute coffee in your portafilter. Use a pin with the Weiss Distribution Technique or a Pullman Chisel/OCD.
  VST baskets are replacement baskets for your portafilter with filter holes positioned and sized to aid uniform extractions. Would recommend getting one.
  Grind uniformity is also a thing to keep in mind. Higher quality grinders will result in a lower deviation in particle sizes of the resulting coffee grounds. Lower deviation means more consistency in extraction.
  Use a scale and a timer to weigh and time your shots. You will need to know what you did in order to know how to improve it.
  When chasing a good shot, change one variable in your method at a time. If you change multiple, you will never know what contributed to making your shot great.