To make the perfect espresso on your commercial
espresso coffee machine follow these guidelines.
1/ Keep it Hot
The key thing to remember is espresso cools quickly as it is a
small volume of liquid - therefore it is essential to maintain
everything coming into contact with the coffee at a high
temperature. Make sure the machine and group handle (porta-filter)
are hot by running a few dummy espressos before making one for
real. Cups should be kept on the warming shelf on top of the
machine. If you are making the first few espressos of the day
before the machine has seen much action, it is an idea to warm the
cups with a little hot water before commencing.
2/ Crema is King
The best indication of good espresso is the crema. It should be a
light caramel colour with enough consistency to hold half a
teaspoon of sugar on the surface for 3 seconds or more. The
appearance of the crema is an excellent indication of the quality
of your espresso. If the crema is more white than brown, the coffee
is under-extracted and needs either a finer grind and/or firmer
tamping. If the crema looks burnt or is very dark in the middle,
the coffee is over-extracted; perhaps the grind is too fine, the
dose too large, the tamping too hard, or too much water has run
through the coffee.
3/ Under Pressure
Tamping the coffee is the process of compacting 7g of ground coffee
in the porta-filter with a tamping device. Use the tamper on the
underside of the grinder or a hand held tamp. Apply firm
pressure - enough to hold the grind when the porta-filter is turned
upside down, but not too firm, otherwise this will lead to a longer
extraction time.
4/ All in the Timing
Perfect espresso takes 18-23 seconds plus 2-3 seconds pre-infusion
time - too long means your coffee grind is too fine, the coffee
should be the texture of coarse sand. If the coffee is too
fine your espresso will be harsh and bitter from over-extraction.
Less than 18 seconds means either your coffee grind is too coarse
or the tamp pressure is insufficient. An under- extracted
coffee will result in a thin bubbly crema and weak espresso.
5/ The Mouse's Tail
Look at the flow of the liquid when making an espresso - it should
be constant and resemble a mouse's tail. If the tail is too thick,
the coffee grind is too coarse or the tamping is too light. If the
tail drips and bubbles, the opposite applies.