There are lots of things that can go wrong in the coffee making process. Follow this 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
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.
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.
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
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.
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.
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.