Coffee-Direct Brewing Guides – The Espresso Machine

Espresso style coffee is brewed by forcing pressurised hot water through finely ground coffee, creating a generally thicker coffee compared to other brewing methods and forming the basis of many popular coffee drinks, including creamy latte or cappuccino. Brewing using an espresso machine is one of the most popular methods to create coffees worldwide.

Early steam-pressured espresso machines were generally used in cafés to quickly prepare regular strength coffees, but these machines were not able to generate the pressure required to create the strong, powerful espresso drink we enjoy today. A breakthrough came with the arrival of Achille Gaggia’s invention – an espresso machine that used a large lever to compress a spring that, when released, forced pressurised, very hot water through the ground coffee. This sudden increase in pressure allowed the use of much finer ground coffee and produced a smaller, stronger, well extracted cup.

Why Brew with an Espresso Machine?
For many connoisseurs, the espresso is the purest distillation of coffee, capturing the true essence of the bean. For espresso lovers, one of the key features is not only the strength of the drink but also the layer of dense foam that tops the drink, known as the ‘crema’. The crema is formed when water is under very high pressure and is therefore able to dissolve more of the carbon dioxide present in freshly roasted coffee beans.

The crema on the top of an espresso can tell you two things:

1. How fresh the roasted coffee beans are - the longer ago the coffee beans were roasted, the less carbon dioxide they will contain and the less foam will be produced
2. Whether the espresso is strong or weak - the darker in colour the foam, the stronger the espresso liquid will be (darker roasted coffees will produce a darker crema).
   
   
   
   

How to Brew an Espresso Shot

1. Fill the reservoir in the espresso machine with water, ideally with a low mineral content, then switch on the machine to heat the water
2. Grind the coffee just before you begin brewing to ensure the freshest flavours. It is best to weigh the ground coffee, so that you can find a recipe that will consistently deliver the best results
3. Ensure that the basket is clean and dry before use, and that any leftover grounds have been removed
4. Add the weighed ground coffee to the basket and tamp it flat, making sure that the coffee bed is even (by leaving the tamper on top of the coffee, you can see the angle to determine whether or not it is flat)
5. Turn on the espresso machine to flush some water through the group head, which will help to stabilise the temperature of the brew water and rinse off any coffee grounds remaining from the previous brew
6. Carefully lock the handle into the machine and put a cup in place to receive the coffee
7. It is encouraged to time the shot – if the machine does not have a timer to show how long the shot has been brewing, you can simply use your own timer
8. Once the handle is locked in place, aim to start brewing as soon as possible. Start your timer and brew the shot for the time recommended by the roaster, or between 27-29 seconds. You can then adjust this timeframe as you develop a personal recipe
9. When the desired brew time is up, stop the machine. When the handle has finished dripping, the espresso is ready to be enjoyed, or combined with steamed milk or milk froth.
   
   

Tips for the Perfect Espresso Shot

As you brew more shots, you will begin to know which recipe works best to your taste, and this will include the weight of ground coffee, the fineness of the grind and the ratio of water to ground coffee.

Adjusting the Grind
When using an espresso machine, you might want to grind beans yourself, ideally using a quality burr grinder that will allow you to easily adjust the grind size.

If the following occurs when brewing a shot, there are some easy fixes:

• If there is too much liquid, then flow was too fast. This can be fixed by grinding the coffee finer
• If there is not enough liquid, the flow was too slow. This can be fixed by grinding the coffee more coarsely.
  
  

Brew Ratio
With the different styles of espresso drinks and personal taste preferences, you will likely want to experiment before settling on an espresso recipe, including the brew ratio or how much liquid you would like to produce from a fixed weight of ground coffee.

A good rule to start from is one part ground coffee to two parts liquid. So, for 18g of ground coffee, you will want to brew 36g of espresso, and you can achieve this by weighing coffee grounds and weighing the finished espresso shot, then adjusting the water flow time and grind coarseness accordingly until you have your perfect recipe.

Tamping
Tamping is the term used for the compression of ground coffee in the portafilter basket before brewing. Because ground coffee is fluffy, air pockets will be present in the basket and the pressurised water would find these, passing through quickly and skipping a large amount of the coffee. This occurrence, known as ‘channelling’, results in an espresso that will taste sour and unpleasant, because the water has not evenly extracted the ground coffee.

The goal of tamping is therefore to push the air out of the coffee bed and to make sure the bed is level and even, prior to brewing.