Perfecting the art of delicious and consistent espresso shots? Look no further! This guide aims to provide you with a deep understanding of crafting the perfect espresso. Step by step. From understanding extraction times to mastering the grind, we delve into every aspect that contributes to that delightful cup of coffee.

Whether you're a barista aiming to refine your skills or a coffee enthusiast eager to understand the science behind your favorite brew, this article offers insights, tips, and techniques to elevate your espresso-making prowess. Let's dive right in and explore the intricate details that make each espresso shot a masterpiece.

 

USE FRESH COFFEE

Quality coffee beans are like bread, they age and go stale quickly and they're really only 'fresh' and full of flavour for a few weeks after they're roasted. For the best cup of coffee, you need fresh coffee beans, stored correctly and ground to the right courseness as the shot is being prepared. This article explains more about how to find the best coffee beans. You can learn more about how to store coffee here. And how to choose the right coffee grinder here.

 

EXTRACTION TIMES

Using a Single 9-11g basket:
A 30ml single espresso should extract between 27 – 35 seconds.

Using a Double 18-21g basket:
A 30ml single espresso should extract between 15 - 20 seconds.
A 60ml double espresso should extract between 27 – 35 seconds.

 

DIFFERENT SHOT VOLUMES
Let's start with the basics... different shot volumes allow for different cup sizes.
Industry standards for an 8oz cup is a 30ml shot, 12oz cup takes a 60ml shot and the 16oz cup requires 90ml of espresso.
From a double basket the maximum shot size is 60ml, so for the 16oz cup you would drop a 30ml and then a 60ml shot into that cup. This requires you to pack that handle with two separate doses of coffee.

Commercial espresso machines will generally be volumetrics, meaning that the buttons on the machine will be programed to give you a measured amount of water. One button will be programed for a single shot (generally 30-40ml) and a second will be programmed for the double shot (60ml).

 

WHY DOES THE EXTRACTION TIME MATTER?
Controlling the amount of time the water is in contact with the ground coffee is one of the key ways to control the flavour of your espresso. Parts of the coffee bean of are soluble, meaning a portion of the bean dissolves during the extraction process, approximately 18 – 32% of the bean is soluble. A balanced and tasty espresso shot is found when between 18 – 22% of the bean has dissolved, so controlling the extraction time will control this, which controls the flavour.

An espresso shot is a balance of the Acids, Oils, Sugars and the Bitterness that is extracted from the coffee.

A shot that extracts too quickly will be high in acid but low in Sugar and Oil, so the coffee will taste sour and will be thin and watery (under extracted).

A shot that extracts too slowly will be over powered by the bitter flavours coming through, the sweetness and bright acids will be lost giving a coffee that tastes smoky, ashy and overly bitter aftertaste. (Over extracted).

 

HOW TO DROP A SHOT STEP BY STEP

The espresso machine will control the volume and the temperature of the water for the espresso shot. The barista controls the time of the espresso shot.

The three key factors that affect the correct extraction time of an espresso shot are: The Dose, The Tamp, and The Grind. The coffee machine only controls the volume and the temperature of the water, how the barista manages the dose, the tamp pressure and the grind is what will affect the shot time and therefore the flavour of the coffee.

1. THE DOSE
This is the amount of ground coffee that you are putting into the basket in your group handle. Having this amount correct and consistent is the first factor that will affect your shot time and therefore the flavour of your espresso.

How do I know how much to use? The size of your basket will determine the amount of your dose. If you are using a single basket your dose should be 11gms. If you are using a double basket your dose will be 21gms of coffee. An accurate way to keep your dose consistent is to weigh your dose.

Why does the dose matter? The amount of ground coffee in the basket will regulate the speed of the flow of water coming from the group head and therefore your extraction time. Too much coffee in the basket and your extraction time will be too slow, not enough coffee in your basket and the extraction time will be too fast.

You can also “Split a shot” meaning you can position 2 cups (4oz or 8oz) under the double group handle, hit the 60ml button and extract 2 x 30mls espresso.

2. THE TAMP
Once your basket has the correct dose, the next step is to tamp the ground coffee. Tamping is applying pressure to the ground coffee to create a firm, level bed of coffee for the water to evenly travel through. Industry standard is a 10-12kgs of pressure.

i. Pressure
Place your palm on the top of the tamper handle and bring your fingers down so they are resting on the ‘ledge’ of the tamp handle. Standing with your hip to the bench, position your arm at a right angle so that your elbow is above your wrist, the tamper base should be placed evenly over your dose and one firm push into the coffee at a pressure of 10-12kgs. A calibrated tamp will ensure consistent pressure or use your bathroom scales and practice tamping on to the scale until you consistently reach 10-12kilos of pressure.

ii. Polish
Release the pressure from the tamper and polish the coffee by gently twisting the tamper on the top of the coffee. This will level the surface of bed of coffee ensuring an even extraction.

iii. Clean
Using your hand, wipe any excess coffee grinds from the top of the basket and the lugs, doing this will help stop coffee building up on the rubber seal in the group head.

3. THE GRIND
The grind refers to the particle size of the ground coffee. The size of the grind will affect the speed of your extraction. Having the grind too fine will cause an over extraction and having the grind too coarse will cause an under extraction.

For consistency of shot times work on keeping your dose and your tamping pressure the same and only adjust the grind to alter your shot times.

4. LOCKING IT IN
To lock the handle in move your hand closer to the basket, the handle is pointing at you, at 6 o’clock – move the handle to the left and you will feel the lugs click up and in and then bring the handle back to 6 o’clock until it feels tight.

Drop a double shot, 60ml and look for a shot time of between 27-35 seconds – start the shot and then start your timer. It should take 3 – 5 seconds before you start to see the espresso extracting – this delay is classed the infusion time and is included in your total shot time.'

 

WHY WOULD YOU NEED TO ADJUST THE GRIND?
You'll likely need to adjust the grind if your shot times and therefore the extraction are not where you want them to be. If you over extract (because the coffee is ground too fine) it will taste burnt and/or bitter. If you under extract (because the coffee is ground too coarse) it may taste grassy or medicinal. Adjusting the grind is something that may need to be done on a daily basis, and in a busy café environment, it may need to be done multiple times a day. Remember; coffee is a fresh food product that deteriorates over time and is affected by exposure to oxygen, sunlight and moisture and your grind might need to be adjusted as the coffee or environment ages.

 

WHEN TO ADJUST YOUR COFFEE GRINDER
Before adjusting the grind check that your dose is correct, you can do this by weighing out your dose or checking the puck after the shot has extracted. The puck (or biscuit) is the coffee left in the group handle after extraction. A correctly dosed basket will leave a puck that is smooth, dry and firm – it should be firm enough to just leave a thumb imprint if you press into it. When you knock the puck out the basket will be clean and dry. If the dose is correct but you shot time is too fast or slow, then adjust the grind finer or coarser.

If you have under dosed your basket the puck will look wet and uneven, there will usually be small holes in the puck, this is due to channelling, meaning the water has quickly drilled through the coffee rather than slowly extracting. The puck will also be very soft and easy to push you finger into and grinds will be left inside the basket when you know the puck out. If you have under dosed the basket, increase your dose to the correct amount and then only change the grind if the shot time is still incorrect.

If you have over dosed your basket the puck will be very hard and you won’t be able to leave a thumb imprint in it. You may have also struggled to lock your group handle into the machine. When you knock the puck out you may see a dark brown residue in the bottom of the basket – these are the oils from that coffee. If you have over dosed the basket, decrease your dose to the correct amount and then only change the grind if the shot time is still incorrect.

 

HOW TO CHANGE THE GRIND

Grinders will have either an adjusting collar or a dial (domestic) that will allow you to change the grind.

When you adjust the grind you are moving the burrs inside the grinder. Grinders have 2 burrs inside them that grind the coffee, the closer the burrs are the finer the grind will be, the further apart the burrs are, the coarser the grind will be.

The bottom burr spins when you turn the grinder on, the top burr is attached to the adjusting collar and moves up or down when you move the collar. Generally for most commercial grinders turning the collar clockwise will make the grind coarser and turning the collar anti-clockwise will make the grind finer.

When adjusting the grind you only want to make very small adjustments of around 0.5 – 1 notch. Roughly speaking a 1 notch adjustment will alter your shot time of approximately 5 seconds.

After making a grind adjustment it is important to clear out any pre ground coffee sitting in the dosing chamber and the dosing chute. This coffee won’t be at the adjusted finer or coarser grind, so if you don’t clear this out and use it, you won’t see a change in your shot time.

Small adjustments are recommend and will allow you to fine tune the grind and get the extraction time you are looking for.

Which way?
Clockwise = Coarser
Anti-Clockwise = Finer

How far?
Approximately, a one notch adjustment will equal 5 seconds on a shot time. So small adjustments on the collar is needed.

Often dialling the grind in will take more than one adjustment. After changing the grind and clearing out the coffee, reload your basket and weigh out your dose and drop and time another shot – if the shot is still too fast or too slow make another adjustment on the grind. And repeat until you get your correct shot times.

 

SIGNS OF A GOOD EXTRACTION

1. TIME
As discussed time is one way to know you have a good shot. Using a timer is easy and reliable. Start your timer as soon as you hit the button and stop the timer when the espresso pour finishes. The shot time also includes the ínfusion’ time.

2. THE POUR
How does the espresso look as it’s pouring? Is it gushing out really quickly, or is it dripping out really slowly? What we are looking for today is what is called a ‘mouse tail’ pour. The espresso should be a steady stream of, thick at the top and tapering down to a point – like a mousetail. Or honey dripping off the back of a spoon is another description.

The espresso will be very dark, almost black for the first few seconds, it will then change to a dark golden pour, that should look thick and ‘oily’ and then art around the 25 second mark (for a 60ml shot) the colour will change to a lighter pale yellow colour – this is called the blonding. This is the natural progression of the extraction.

3. THE CREMA
The colour of the Crema in the cup is another good indicator of a well extracted espresso. A shot that has extracted correctly will give a dark gold thick head of crema floating on top of the black espresso. The crema should be 3-5mm thick and this is included in the 30 or 60ml shot, you always measure the espresso to the top of the crema.

A thin and pale coloured crema is a sign that you shot has extracted too quickly, meaning your grind could be too coarse, or you have under dosed your basket

4. THE PUCK
The puck or biscuit should be firm and dry and should not leave too much residue inside the basket when tapped out. A puck that is soft and wet is an indication that you are under dosing.

 

3 REASONS TO ADJUST YOUR GRINDER

1. Changes in the weather - Because coffee is affected by moisture, changes in the weather can start to affect the speed of extraction of the espresso shot. When it is very hot and humid, or rainy or foggy, because of the increase in humidity you can find that your espresso shots will begin to slow down. Adjusting the grind to slightly coarser will allow the water to flow more easily through your bed of coffee and speed our shot up to the required shot time. As the weather changes through the day you may need to make slight adjustments.

2. Age of the coffee - As the roasted coffee ages gases and oils are slowly released, remember in the first 5-10 days after roasting the coffee is degassing. Using a coffee that is closer to the roasting date may require a finer grind, as that batch of coffee ages over 2-3 weeks you may need to keep adjusting the grind. A new delivery of coffee that has a different roast date may require an adjustment to your grind to compensate for the age of the beans.

3. Changing the coffee - Changing the coffee you are using may also require an adjustment in your grind. Changing the blend you are using means you will have completely different beans going through the grinder – different sizes, different moisture levels. Changing from a blend to a single origin may also mean an adjustment on the grind is required.

 

KEEP IT CONSISTENT
The simple way to control your shot times is to keep your dose consistent, keep your tamping pressure consistent and then you are only adjusting the grind according to the shot times. Finer to make the shot slower and coarser to speed the shot up.

Goodluck!