The Methods And Machines Behind The Perfect Espresso

There are many variables when making the perfect espresso. The ability to pour a perfect espresso is a gift once you discover what secrets lie within the mighty coffee bean you will find yourself on a mission to achieve a perfect espresso with every coffee you produce. You have the ability inside you to produce a perfect espresso and now it is time to learn how.

Having the ability to make a perfect espresso will also provide you with employment opportunities whenever you are short of cash. Baristas with passion are in big demand as more and more of society is starting their day with a perfectly made espresso coffee.

So what variables can you control when making espresso coffee?

The more experienced you are and the more knowledge you have about coffee the better your coffee will be. The longer you work with coffee the more passionate you will become to find the perfect espresso.

So coffee beans….

There are two major species of coffee beans traded in the world today. Arabica and Robusta. Arabica beans are high altitude grown which develops a delicate, rich flavour of fine quality. Robusta beans are grown at low altitudes and has a higher yield coffee. Robusta beans may tend to have a harsher flavour and these are usually used in commercial grade coffee.

The coffee tree is an evergreen shrub that takes 3-5 years to mature and bear fruit. The berry lke fruit is commonly referred to as coffee cherries. Inside each cherry are two beans. All quality coffee is handpicked and since cherries ripen at different times, there is up to 3 harvests per season. It takes about 2.5 kg of cherries to produce 500g of coffee. The average tree produces only ½ to 1 kg of coffee per season.

Lets roast our beans

Beans are roasted at temperatures of 220C. This heat converts the sugar and starches present in the coffee bean into oils. During roasting the beans swell up to twice their original size. It is the oils that give the coffee the rich flavour and aroma. The longer the beans are roasted the more oils come to the surface. If the beans continue roasting the flavour changes and over roasting can cause bitterness. Different forms of coffee require different roasting times. Espresso coffee requires a well balanced roast which will enhance the flavours and have a balanced flavour profile.

Blending coffees

Beans from different origins are blended to enhance a coffee’s flavour profile. It is best to roast the beans separately before blending as each bean type will take different roast times and produce different flavour when roasted.

So what’s the espresso story

History tells us the French were first to introduce espresso coffee in the early 1800’s.

The Italians first introduced espresso at the turn of the century in 1901 by Luigi Bezzera. Espresso is made by forcing water at high temperatures and pressures (approximately92C and 132 psi) Through finely ground coffee. The result is a concentrated and flavourful extract which is truly “il Cuore del Caffee” (the heart of coffee). The coffee used to make espresso is usually roasted darker to reduce acidity. It is ground just prior to brewing, prepared one or two cups at a time and served immediately. The result should be an intense taste of rich, smooth concentrated coffee that is topped with a layer of fine golden-brown bubbles called “Crema

Get a mean machine

Your espresso machine can be likened to a car. Look after it, clean it regularly, check the water, pressure, seals etc and it will perform well for many years. Conversely, if you are lazy not only will the machine perform poorly and make your coffee taste foul. Also if the machine is not serviced regularly it will require expensive replacement part. It is recommended to get the machine serviced every 6 months with a shower spray, group seal, water filter change and a boiler temperature, pump pressure and steam valve check.

So what is the espresso process?

Traditionally espresso coffee is made by forcing hot water under pressure at approximately 91C + or – 2 C throughout 8 grams of ground coffee at 9 bars pressure + or – 1 bar, for approximately 30 seconds to produce approximately 30 mls of espresso coffee. This process is known as the extraction process. During the correct extraction process the flavour, aroma and oils which also give the crema are extracted from the coffee.

Filter baskets placed in group handles are used to hold the ground coffee . The filter baskets should be filled correctly and tamped down with a tamper until evenly packed in the basket. If you are unable to get the filter group handle in place then the filter basket has too much in it. Empty the grinds and repack. Check the coffee cookie left in the filter basket. If the coffee cookie is wet then there was not enough coffee in the filter basket and it was not tamped correctly. If the coffee cookie falls out in one piece and the imprint of the grouphead is seen on the top of the cookie then the coffee is extracted correctly and your coffee will taste great. The coffee cookie will tell you a lot about the coffee shot even before you taste the coffee. Keep your eye on this.

When tamping the ground coffee make sure the tamp is even. Water always runs to the lowest point and will change the extraction resulting in inferior tasting coffee.

The tech stuff – machine settings

1. Pump pressure

  • Approximately 9 bars (130 p.s.i.) per group when activated.
  • Standing mains pressure approximately 4-5 bars.
  • Low pump pressure results in coffee with little crema and will be under extracted.
  • If pump pressure is too high the coffee will taste burnt and be over – extracted.

2. Boiler pressure

  • Approximately 1.1 bars (16p.s.i) gives a water temperature of approximately 91 C.
  • High Pressure results in hot water that burns and over extracts the coffee.
  • Low Pressure results in under extraction, poor flavour and weak crema.

3. Water level

  • Check the sight glass and water level should be two thirds or three quarters full. If the boiler is too full the water temperature may be too high and steam capacity will be reduced.
  • Both Pump pressure and boiler pressure should be checked occasionally throughout the day. Once set they rarely change, however they should be frequently monitored. If they require changing, ask your technician to adjust them, keeping in mind that their gauges are more accurate than most machine gauges.

The really important stuff

Keep your standards high

Anytime you feel you have brewed a less than perfect cup of espresso. DO NOT SERVE IT! Toss it out and start again. You will be sure to get the perfect proportion. Use a full basket of coffee approximately 8 grams per shot 30 ml shot 30 seconds and 15 mls in 20 seconds.


Use the correct grind taking into account the weather, blend and strength of your ability. The grind greatly affects the quality of the espresso. When the coffee is in the basket it should be tamped evenly and should reach the line in the basket. It is very important that the coffee is tamped evenly.

The grind for espresso is fine. The grind is critical in achieving good extraction and producing a quality cup of coffee. It contains about 5 million particles per gram which equates to over 40 million particles per cup.

Other important points in regard to you grinder

  • The oil from coffee beans builds up on the hopper and becomes rancid which will impact off-tasting flavour to your espresso. Clean the grinder hopper daily with a damp cloth and then dry with a dry cloth. Never use a scourer as this will scratch the service and allow oil to get trapped.
  • Clean the inside of the of the dosing chamber daily to remove coffee buildup and to ensure a consistent dose.

So why is the correct grind important?

The correct grind is critical in achieving good extraction and producing a quality cup of coffee. It contains approximately 40 million particles per cup. The grind can vary throughout the day as factors such as temperature, humidity and machine load change. These variations maybe small but they do affect the quality of the espresso and can result in inconsistency over the day. A trained barista will recognise these changes usually by a change in the extraction flow or time and will make adjustments to the grind to compensate.

Adjusting the grind

Adjusting the grind is one of the most important variables in producing good espresso. It requires constant adjustments and with experience it is a skill that can and MUST BE MASTERED.

All grinders are slightly different, however they work on the same principles. The blades are moved closer together for a finer grind and further apart for a coarser grind. Some collars on the grinders may have a “= “or “– “sign on them. “= “means coarser and “–“ means finer. When you have the spot where the coffee is perfect, mark the setting with liquid paper as this will assist you to find it again easily after moving the collar. The grinder also may need to be changed with different bags of coffee. There are usually minor differences in the way the beans grind in a freshly opened bag.

When changing the grinder only change it a little bit at a time. There is only a minor adjustment needed. Too far and the grind will be too coarse and the coffee will be destroyed.

So when is the grind correct?

If the grind is correct there will be approximately a 4 second delay after you have activated the brew button, before the coffee liquid appears. The flow will soon be smooth with a rich honeycomb, golden brown crema. The extraction time to test your grind if correct will be approximately 30 seconds for a single regular (30ml) espresso shot and the same for a double regular (60ml) espresso shot.

Some tips on making the best espresso shot

  • Cleaning a grill after you use it can be a big pain. Right after your grill cools down, you can use some coffee grounds to scrape away at any stuck on food.
  • If you do go to a coffeehouse for a cup of joe and work away from home, be careful how you place your laptop. You do not want to spill your drink on it, nor do you want anyone reading your screen over your shoulder.
  • Clean your coffee grinder regularly. Coffee grinds go stale quickly.
  • If you tend to drink a lot of coffee, you should invest in a quality coffee machine and make your own coffee at home. Go to a coffee shop only occasionally, for instance on weekends or when you go out with some friends.
  • If you want to keep your coffee hot in the pot, warm up the pot beforehand by putting hot water into it. Insulated carafes work best, as you should never let coffee spend time on top of a warming plate.
  • Only use cold water in your coffee machine. Using hot water in your brewer will scald the beans and your coffee will taste bad.
  • No matter how attached you are to your favourite blend, don’t be afraid to try a new variety. You don’t need to invest in a large bag to try out something new.


Ann is an affiliate manager at .  She has been an affiliate makerter for almost 2 years. She loves all things related to coffee, especially espresso.

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