COFFEE CREMA - HOW IS IT FORMED, AND WHAT DOES IT SAY ABOUT YOUR ESPRESSO
Crema is the foam that forms on the surface of the espresso during extraction. Its formation is influencing by the processing method, extraction, and the freshness of the roast.
Research has shown. The guests pay attention to the presence of a crema. Such a drink visually seems to them to be of better quality and tastier. Perhaps the point is that coffee made with cream is more photogenic. Guests are used to this picture and believe that this is how a "real" espresso should look. Therefore, they are alarmed if the barista serves espresso with little or no crema.
The professionals of the coffee industry argue that crema is not indicating the taste of a drink. At the barista championships, only the presence of crema is now evaluating. Color, texture, density may vary.
We will figure out what crema is and how it affects the taste.
How the crema is forming
The crema is formed during the extraction process when pressurized water passes through the coffee tablet. Typically, foam consists of the following components:
- Carbon dioxide is formed during roasting and is released two weeks after it.
- Melanoidins are a byproduct of the Maillard reaction and are also forming during the roasting of coffee beans.
- The oils, proteins, sugars, and others were initially in the grain.
Pressurized water flows through the coffee tablet and dissolves carbon dioxide. Melanoidins - large hydrophobic molecules - surround themselves with gas bubbles. In this way, they provide themselves with protection from water and stabilize the bubbles. When pouring out, the pressure of coffee is normalizing, and gas bubbles float up. If coffee contains large amounts of heavy essential oils, their large molecules pull the melanoidins down. The bubbles start to burst.
High water pressure is the head condition for crema formation. It is the only way water can dissolve carbon dioxide in itself, which will subsequently create foam. Therefore, alternative brewing methods - funnel, Chemex, French press, and others - do not form a cream.
What affects the formation of the crema
The absence or presence of crema is influencing by many factors: the processing method, the type of coffee, the extraction, and the freshness of the roast.
- Processing method
Naturally processed grains usually yield more crema. It happens because coffee contains more oils, proteins, and sugars. These components contribute to the formation of a stable crema. Washed coffee produces little crema because the content of these substances is lower.
Robusta gives more crema than Arabica because Robusta has a higher extraction rate. Consequently, more carbon dioxide is producing. The drink itself is more concentrated. The crema is stable but loose. Arabica also gives crema, but less - denser and with a high content of aromatic compounds.
If the coffee is not sufficiently extracting, the crema will be light, fluid, and quickly disappear. The cause of under extraction may be coarse grinding, insufficient coffee, low water temperature. Over-extracted coffee has a dark, uneven, and bubbly cream. The reason is the opposite - too fine grind, too much coffee, high water temperature.
- Freshness roast
Freshly roasted beans will produce more crema. It is because in the first two weeks after roasting, the grain continues to emit carbon dioxide. When the gas begins to come out, the crema becomes less.
If you like having a lot of cream on your espresso, use a Natural or Hani Grain, Arabica, and Robusta blend fried less than two weeks ago. Make sure that the conditions for good extraction are meting: water temperature, the dosage of ground coffee, size of grinding. We wrote more about this in the espresso brewing guide.
Crema is a significant part, but not a guarantee of great taste.
The presence of crema does not guarantee the quality and taste of the drink. Therefore, you should not give up coffee that does not have sufficient, in your opinion, amount of cream. Try the drink before judging its taste.