Espresso Rules


Under-extracted espresso tastes excessively sharp and acidic. Properly
extracted espresso has the sweetness to balance the acids and
bitters. Over-extracted espresso tastes dull and tarry, or just


    * Under-extracted: Do the fruit acids taste sour, the maillard
       compounds sharply bitter? It's under-extracted.

    * Properly extracted: Do the fruit acids taste crisp, and the
      maillard compounds warm and round? It's properly extracted.

    * Over-extracted: Are dull or tarry tastes overwhelming everything
      else? Is it mostly bitter-sweet caramels and molasses with
      nothing else? It's over-extracted.





Jim Schulman Says

Dose, temperature, pressure, and flow rate all affect the way the the
coffee is extracted. Varying these has only a slight effect on the
aromatics, but a large effect on mouthfeel, and the taste balance,
that is, the balance of bitter, sour, and sweet flavors.

There is a good deal of overlap to the effect of changing some of
these variables. For instance, both more lungo extractions and cooler
temperatures tend towards acidity, while both more ristretto
extractions and higher temperatures tend towards bitterness. Every
barista must develop his or her own competence in diagnosing the taste
imbalances of a shot and changing the shot variables to correct
them. Depending on machine and grinder, they'll pick one or two "go
to" variables from the quartet of the dose, flow, temperature, and

Currently I use dose and flow, and leave temperature and pressure
be. You can use another set of variables, but my advice is to focus on
these two first, since they are 'Mano" variable, available on any
machine, whereas temperature and pressure may only be adjustable on
some machines.