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How to Brew the Perfect Espresso – Part 2

Barista tips

In Part 1 of our Guide To The Perfect Espresso, we explored through how to select, grind, dose and extract your coffee beans to achieve a great café-quality coffee at home.

Now let's take a look at some common mistakes in the coffee making process. Follow our troubleshooting guide for problem-solving during Espresso extraction and you can’t go wrong!

There are five factors you need to consider when judging your rate of extraction:

1. Particle size and adjusting the grind
2. Dosage of ground coffee being dispensed
3. The pressure you apply to the coffee
4. The pump on your machine
5. Environmental factors 

Particle Size and Adjusting the Grind

  1. Remove any ground coffee from the grinder dispenser.
  2. Put in an airtight container in a cool dark place NOT the fridge or freezer. If the grind is too course you may be able to use it in your plunger. (Never re-grind)
  3. Clean the dispenser with a paintbrush and dispense any coffee grounds.
  4. Turn the grind adjustment in the appropriate direction. (i.e. either finer or courser)
  5. Only turn the grind adjustment 1/2 a cm at a time
  6. Dispense the required amount of coffee (min 18g) into your double portafilter
  7. Extract 2 x espresso and time the extraction,
  8. If the extraction is not 25-30 sec for 25-30ml the grind is not correct, and you will need to make the appropriate adjustment. If adjust the collar 1 notch (½ cm).
  9. If it's pouring too fast, adjust the grinder in the Finer direction.
  10. If it's pouring too slowly, adjust the grinder in the Courser direction.

Repeat process until extraction is correct!

Hint: You can use a white marker to indicate the current setting on the grinder this setting may change from day to day. The mark you make is only a reference guide. Weather, bean types and blade condition all have an affect on your ground coffee.

Dosage of Ground Coffee Being Dispensed

For properly prepared espresso, the recommended dose is minimum 9g per single group handle, and 18g for a double group handle. For every gram of coffee used there should not be any more than 3 ml of water passed through the ground coffee. If any more than 3ml of water is passed through you will be over extracting coffee. This can result in a bitter espresso.

For example:
7 grams of ground coffee x by 3ml of water represents a 21ml extraction
9 grams of ground coffee x by 3ml of water represents a 27ml extraction

The Pressure You Apply to the Coffee

This relies to the tamping pressure applied to the ground coffee in the group handle. When applying pressure with your tamp, strong pressure is required, followed by a tap, then apply same pressure one more with a slight twisting motion. If the pour is too slow, the problem is the grind or coffee dosage, not pressure.

The Pump on Your Machine

Espresso machines can vary from make and model, so check your espresso machine manual and confirm that it is operating with the intended pressure. Some machines will have a pressure gauge to help you with this, if not this will need to be measured by a technician.

Environmental Factors

Changes in weather and humidity can have an affect on the coffee grind and the extraction. As humidity increases you may have to make the grind courser. If weather conditions become cooler with low humidity you may have to make the grind finer.

In the final part of our Guide to the Perfect Espresso, get our step by step guide to preparing just some of the many espresso varieties including Ristretto, Doppio, Macchiato and more. 


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