Crema belongs on espresso like foam belongs on Guinness. You can easily conjure up a beautiful crema on your espresso at home - but there are a few simple rules you need to follow. You can find tips for the preparation as well as for the choice of coffee and roasting in this article.
21 possible mistakes why you can't get a proper crema on your espresso
The perfect espresso is full-bodied and has a beautiful crema! The crema is part of the look of an espresso, but it also influences the aroma, mouthfeel, taste and aftertaste of the coffee. Unfortunately, it often doesn't turn out right - and most of the time the coffee doesn't taste the way you want it to. You can find the typical mistakes and the corresponding solutions here.
1. Your coffee is ground too coarsely
It is perfect if the espresso takes between 20 and 30 seconds to extract. If you have ground 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 ground too finely
Here the opposite of above happens: the coffee runs through the sieve much too slowly or hardly at all. 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 use too little powder
This leads to the same effect as in point 1 - your coffee is under-extracted. To find the perfect grind and the right amount, you should only adjust 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 tamp it down a bit.
4. You take too much powder
Well-intentioned, but unfortunately it doesn't help. With too much ground coffee in the sieve, the coffee will be over-extracted. Again, we recommend that you adjust only one aspect at a time and work your way towards the perfect extraction.
5. Your water is too soft
Very soft water (< 0.7mmol/l) means that your espresso hardly forms any crema. You have four options:
- If you filter your water - don't use the filter, you probably don't need it.
- Ask a friend who lives in the midlands to send you a canister of water and mix it with yours.
- Use bottled water.
- Enjoy the soft water - you'll never have to descale your machine.
6. Your machine is not clean
Coffee oils and other deposits in the machine and in the filter are the enemy of a beautiful crema - and affect the taste. Clean your machine regularly. You can find tips and the right products at a specialist dealer.
7. Your cups are not clean
Honestly: You buy a great espresso machine and a high-quality grinder for more than 1,000 Swiss francs, take the time and leisure to roast yourself a perfect coffee, watch YouTube tutorials on perfect espresso extraction every free minute - and then you're too lazy to clean your cup?
Shame on you. You will be punished with a tired and thin crema.
8. Your coffee is too old
The oils in the coffee are mainly responsible for the crema. When the hot water is forced through the powder at high pressure, these oils are dissolved out of the coffee powder along with various proteins and sugars. Under the high pressure, the water becomes saturated with CO2 and the insoluble substances in the water swirl. This is how the finest foam bubbles are formed. This aromatic foam eventually collects on the surface of the cup. If you add a little sugar to the espresso, the crema will hold it for about three seconds.
If the coffee is old, the essential oils and the CO2 have already evaporated - the coffee tastes boring and the crema may no longer form. So always drink your coffee as fresh as possible.
By the way: You can easily roast your own coffee at home - then you are guaranteed to always have fresh coffee to hand. What's more, you have full control over which beans go into your espresso blend - see mistakes 18 and 19.
Coffee roasters for the home:
9. Your coffee was ground too early
Grinding breaks up the structure of the coffee and thus increases the surface area that is exposed to the air and thus to oxidation. This is why the above-mentioned processes take place much faster than with unground coffee. If possible, you should consume ground coffee within 30 minutes.
10. Your coffee has been in the grinder too long
Again, we refer to points 8 and 9. Since your coffee was no longer in the protected and sealed coffee bag, but openly in the grinder, all the oxidation processes take place much more quickly. In addition, many of the coffee beans slide all along the bean container, leaving the coffee oils behind. You've probably also seen grinders that look all sticky and dirty - not a pretty picture for an espresso and crema lover.
11. You have tamped too weakly
This also leads to a too fast throughput time and an under-extraction of the coffee. Orientate yourself to 9kg pressure when tamping. You can find many excellent YouTube videos on this, watch a few of them. You can improve your coffee massively with small changes in technique.
12. You have tamped too much
If you press the coffee into the sieve with too much pressure, the powder is pressed so tightly that the water hardly flows through and your coffee tastes over-extracted, bitter and sharp. The crema is dark brown, uneven and shows air bubbles.
And beware: many baristas knock on the sieve with the tamper after tamping or are a little careless, so that the portafilter still hits somewhere on the machine. This can cause small cracks in the pressed powder. The water seeks the "path of least resistance", flows through these small cracks and can only loosen a 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 gauge so you can check the temperature of the water before and during extraction. A water temperature below 88°C will result in under-extraction, sour and thin coffee, and a barely-there crema.
14. The water is too hot
On the other hand, water that is too hot, above 94°C, leads to over-extraction and a thin, dark brown to blackish crema with a white spot or a black hole in the centre.
15. The pressure is too low
See also point 8 - Espresso needs pressure. Too little pressure means that not enough particles are released and your coffee is under-extracted, the crema barely present. The pressure should be around 9 bar. Your espresso machine must be able to do this. At the same time, too coarse a grind, too weak a tamp or too little ground coffee can lead to insufficient pressure building up - so 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 be able to build up more pressure than 9 bar. This will happen (probably no surprise after point 15): if the grind is too fine, if the tamp is too tight or if there is too much ground coffee. So, correct all the above factors to get to the 9 bar pressure.
17. Home roaster only - your coffee is too fresh
If you don't roast your own coffee, you can skip this chapter, because he or she will hardly ever get into the situation where a coffee is too fresh. Most of the coffees on the shelves are weeks, if not months, old, so they almost never show a roast date.
As a home roaster, you may remember the first time you extracted a freshly roasted espresso - the crema was spectacular! This has to do with the fact that there is still enough CO2 in your fresh coffee, which dissipates very quickly after roasting and especially after grinding.
At the same time, this carbonic acid overlays the fine nuances of taste in your coffee. This is why the espresso only becomes really good about 4-5 days after roasting. If you have the patience, we recommend that you leave the coffee to stand for a few days after roasting.
18. You have chosen the wrong coffee
Not all coffee varieties and processing methods produce a perfect crema. That's not too dramatic, because first and foremost you should look for the flavour that suits you best. As a rule of thumb, you can orientate yourself on the fact that natural and honey-pulped beans (see also processing) usually have more sugar and oils than washed coffees and therefore allow more crema.
For home roasters, we recommend these balanced green coffees with nutty-chocolatey or spicy-sweet notes:
19. You don't have Robusta in the espresso blend
Robusta makes a denser crema. This is not a secret trick, most Italian espresso blends have a proportion of Robusta of about 25% because of this. Unfortunately, there are many inferior Robustas that taste like burnt rubber or railway track. Make sure you use a high-quality Robusta.
We recommend these Robustas to home roasters:
20. Your coffee is roasted too light
A roast that is too light (around the first crack) can cause your crema to become a little pale and collapse quickly. However, you don't need to have too much respect for this, you can roast the coffee quite light (e.g. City - see the knowledge section for roasting degrees) and still extract an espresso with a clean and beautiful crema.
21. Your coffee is roasted too darkly
If your coffee is roasted too dark, you will often have less crema. This is because after the second crack (see also in the knowledge section), oil droplets come out of the beans, which get stuck in the bag and in the grinder during storage. As a result, you have less oil in the powder and thus less crema.
Espresso checklist for crema
- freshly roasted coffee
- freshly ground coffee
- natural or honey-pulped beans in the blend
- At most some Robusta in the blend (not a must)
- Ideally full city roast (until just before second crack)
- 25 - 35 ml water
- 88 - 94°C water temperature
- 8 - 10 bar pressure
- 20 - 30 sec. brewing time
I hope this information helps you and wish you from now on only excellent espresso with a beautiful crema. If you have any questions, please do not hesitate to contact me!
More questions? We are here for you.
Do you have any further questions about coffee, roasting or our range? Feel free to call or email me at any time. As a home roaster, SCA trained roaster and member of the Roasters Guild of Europe, I know the equipment and coffees from my daily work:
Phone +41 76 261 97 17 or email ingo[at]roastrebels.com
