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Learn to make perfect espresso coffee
Posted April 2, 2006
 
Espresso coffee is an Italian invention that uses a pump-driven machine to force near-boiling water through finely ground coffee to extract its full flavour. For best results, the water is forced through with at least 15 bars of pump pressure for 20 to 30 seconds (nominally 25 seconds) to produce 30 ml of liquid. The resulting "shot" of liquid is thick and strong, and contains a dark oily layer on top known as the crema. Espresso coffee drunk "as is" is often referred to as a short black. Hot frothed milk can also be added to an espresso shot in various proportions to make other popular café style coffee drinks including macchiato, cappuccino, flat white, and latte.

To make coffee house quality espresso coffee at home, you'll need to by a good quality domestic espresso machine. These start from a couple of hundred dollars and up. It's not necessary to get one with fancy features. So long as it produces at least 15 bars of pump pressure, the overall quality of the coffee will be the same. Do not buy the cheap ones that operate from steam pressure rather than using a pump to force the water through the coffee as these machines don't make a proper espresso shot.
 

Type of coffee

The perfect espresso coffee is made from freshly-ground roasted coffee beans. This means you'll also need to invest in a good quality grinder and use whole beans. Alternatively, you can buy ready ground coffee. Ground coffee should be stored in an airtight container and refrigerated. Coffee stored in this way will last up to a few weeks but the flavour will slowly deteriorate. 

The coffee beans should be finely and evenly ground to make a good espresso coffee. However, if it's too fine it will clog the filter and won't produce 30 ml of coffee in the requisite 25 seconds. If the coffee is too course the water will pour through too quickly, overfilling the cup, and won't produce a decent crema. You cannot use instant coffee with an espresso machine.

The water

It’s also important to start with fresh clean water. Water that has a stale or plastic taste will affect the flavour of the coffee. This also goes for the coffee making equipment. Make sure the filter, filter holder and group are clean and free of old coffee residue.

Making the coffee

Making the perfect espresso coffee at home takes a lot of initial experimentation as there are many variables that can affect the process including the type of coffee, the grind, and how tightly and evenly the coffee is packed into the filter. The general procedure for making an espresso coffee is outlined below:

» Turn on the espresso machine and allow it to preheat. Make sure it has an adequate supply of fresh cold water.
» Preheat the coffee cups, filter, and filter holder.
» Grind the coffee if using whole beans.
» Place the filter inside the filter holder and add one scoop of coffee (about 7 grams).
» Level the coffee flat with your finger. Now lightly press on the coffee with the tamper. Remove the tamper and allow any grinds on the side to fall back on top of the coffee. Tamp again with a little more pressure while slowly rotating the tamper so that the coffee is evenly packed with a smooth finish.
» Tightly lock the filter handle into the machine and quickly place a warm cup under it.
» Set the machine to force the water through the coffee for 25 seconds (the machine should automatically control the temperature of the water to just below boiling point). The coffee should drip out slowly,  appear reddish brown in colour, and produce 30 ml of coffee with a thick crema. 
» Stop the water flow (if the machine is manually controlled) and drink the coffee immediately.

To make a long black, simply add hot water to the espresso shot. 


Troubleshooting

Some general troubleshooting tips are given below:
Symptom Possible causes
More than 30 ml of coffee in the cup.
  • Grind is too course
  • Insufficient coffee used
  • Coffee not packed tightly or evenly enough
  • Extraction time too long
Less than 30 ml of coffee in the cup.
  • Grind is too fine
  • Too much coffee used
  • Coffee packed too tightly
  • Extraction time too short
Crema is too thin or light in colour.
  • Grind is too course
  • Grind not even (grains not the same size)
  • Insufficient coffee used
  • Coffee not packed tightly or evenly enough
  • Machine not warmed up
Coffee tastes bitter.
  • Extraction time too long
  • Coffee type - try another brand


Frothing milk

Most espresso machines will also produce steam for heating and frothing milk. If your machine is an inexpensive type, draw the espresso shot first before switching to the steamer mode. Place a small saucer over the espresso shot to keep it warm while you froth the milk. When the steamer is ready, expel a little steam first to remove any water. Then position the steam nozzle to the bottom of a jug of cold milk and open the steam valve. Slowly lower the jug to draw the nozzle closer to the surface of the milk so that it can draw in a little air. If you position it right, a whirlpool motion will be happening in the milk and you will get an even mix of bubbles throughout. The frothed milk should be about 70-75° C. Do not scorch the milk or allow it to boil! Turn off the steamer and prime the unit if necessary for your machine. Bang the milk jug down on a flat surface to break up any large bubbles, and swirl the jug around a few times (or mix the frothed milk with a spoon).

Add the milk slowly to the espresso shot to make the desired coffee drink in the appropriate cup or glass. To make a macchiato, simply "stain" the coffee with a little of the frothed milk. Flat white and latte coffees contain about two thirds frothed milk. Cappuccino is made like a flat white but contains additional froth on top and a sprinkle of powdered drinking chocolate. 

Once you get the process right, you'll be the envy of all your friends!

 

 

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