1. Your coffee is too coarsely ground
It is perfect if the espresso extraction takes between 20 and 30 seconds. If you grind the coffee too coarsely, the water shoots through the sieve too quickly and absorbs too few coffee particles - your coffee is under-extracted. The crema becomes light and thin and disappears quickly and the coffee tastes sour and flat.
2. Your coffee is too finely ground
Here the opposite happens from above: the coffee runs much too slowly or hardly through the sieve. As a result, too many parts are dissolved and the coffee is over-extracted. It tastes bitter and slightly burnt. The crema is dark brown, uneven and shows air bubbles.
3. You take too little coffee
This will have the same effect as in step 1 - your coffee will be under-extracted. To find the perfect grind and the right amount, you should adjust only one of the two factors at a time. 7 grams of ground coffee per espresso is in theory the guideline for the perfect espresso - I usually use 10 grams and tampe a little less.
4. You take too much coffee grounds
Well-intentioned, but unfortunately it doesn't help. Too much ground coffee in the sieve over-extracts the coffee. Here too, we recommend that you adapt only one aspect at a time and thus work towards the perfect extraction.
5. Your water is too soft
Very soft water (< 0.7mmol/l) prevents your espresso from forming crema. You have four options:
- If you filter your water - do without the filter, you probably don't need it.
- Ask a friend who lives in the Midlands if he can send you a can of water and mix it with yours.
- Use water from the bottle.
- Enjoy the soft water - so you never have to descale your machine
6. Your coffeemaker is not clean
Coffee oils and other deposits in the coffeemaker and sieve are the enemy of the beautiful crema - and influence the taste. Clean your machine regularly. Tips and the right products can be found at a specialist dealer.
7. Your cups aren't clean
Honestly: You buy a great espresso machine and a high-quality grinder for more than 1000 francs, take the time and leisure to roast a perfect coffee, watch Youtube tutorials for the perfect espresso extraction in every free minute - and then you are too lazy to clean your cup?
Shame on your head. You will be punished with a tired and thin crema.
8. Your coffee is too old
The oils in coffee are mainly responsible for the crema. When the hot water is pressed through the powder at high pressure, these oils are dissolved from the coffee powder together with various proteins and sugars. Under the high pressure, the water is saturated with CO2 and swirls the insoluble substances in the water. In this way the finest foam bubbles are formed. This aromatic foam finally collects in the cup on the surface. If you put some sugar on the espresso, the crema holds it for about three seconds.
If the coffee is old, the essential oils and CO2 have already evaporated - the coffee tastes boring and the crema may no longer form. Therefore always drink the coffee as fresh as possible.
9. Your coffee was ground too early
The grinding process breaks up the structure of the coffee and thus increases the surface area exposed to the air and thus also to oxidation. Therefore, the above processes are much faster than with un-ground coffee. If possible, you should consume ground coffee within 30 minutes. .
10. Your coffee's been in the grinder for too long
As your coffee was no longer in the protected and sealed coffee bag, but open in the grinder, the whole oxidation process is much faster. In addition, many of the coffee beans slide along the whole bean container and leave the coffee oils there. You must have seen grinders that look totally sticky and dirty - not a nice picture for an espresso and crema lover.
11. You tampered too softly
This also leads to a too fast throughput time and an under-extraction of the coffee. Orient yourself to 9kg pressure during the rope. You'll find a lot of great YouTube videos, check out some of them. With small technical changes you can massively improve your coffee.
12. You tampered too hard
If you press the coffee into the sieve with too much pressure, the powder is so densely pressed that the water hardly flows through and your coffee tastes over-extracted, bitter and spicy. The crema is dark brown, uneven and shows air bubbles.
And attention: many baristas knock on the screen with the tamper after the rope or are a little careless, so that the screen carrier still strikes somewhere on the machine. This can cause small cracks in the pressed powder. The water searches for the "path of least resistance", flows through these small cracks and can only loosen little of the coffee powder, so that you get a thin and again under-extracted coffee.
13. The water is too cold
Ideally, your espresso machine has a temperature indicator so you can check the temperature of the water before and during extraction. A water temperature below 88°C leads to under-extraction, sour and thin coffee as well as a barely existing crema.
14. The water is too hot
On the other hand, too hot water with more than 94°C leads to an over-extraction and a thin, dark brown to blackish crema with a white spot or a black hole in the middle..
15. The pressure is too low
See also point 8 - Espresso needs pressure. Too little pressure means that not enough particles dissolve and your coffee is under-extracted, the crema hardly present. The pressure should be around 9 bar. Your espresso machine must be able to do this. At the same time, too coarse a grinding, too weak a rope or too little coffee grounds mean that no sufficient pressure can build up - everything is connected on the way to the perfect espresso.
16. The pressure is too high
If you have a reasonably professional espresso machine, it will easily build up more pressure than 9 bar. This will happen (probably no surprise after point 15): if the grinding is too fine, too firm or too much coffee grounds. So, correct all the above factors to get to the 9 bar pressure.