Crema should have a consistent, thick, and creamy texture. After the shot has been extracted, it should remain for a few minutes and have a golden-brown hue. Additionally, the crema must be silky and smooth without any visible bubbles or significant air pockets. A nice crema will be between one and two millimeters thick and shouldn’t be either too thin or too thick.
There may be creosote in your coffee, which would explain why it tastes like soap. When coffee beans are roasted at high temperatures, a substance known as creosote may develop. Unpleasant chemical or soapy flavors may be added to coffee as a result. To prevent this, try using freshly roasted coffee beans or roasting your own beans at a lower temperature.
Lack of crema on top of the shot is a sign of under-extracted espresso. If there is no crema, the espresso has not been extracted properly. Crema should be thick and creamy. Because the hot water did not have enough time to fully liquefy the coffee grounds, the shot can also taste sour or acidic. Try changing the grind size, the tamping pressure, or the brewing time to resolve issue.
Over-extraction may be at blame if your coffee suddenly tastes bitter. Coffee that has been over-extracted may taste burnt or bitter, and its crema may be weak and watery. If the coffee is ground too finely, the brewing process takes too long, or the water temperature is too high, this can occur. Try modifying the grind size, brewing duration, or water temperature to resolve issue.
Espresso is typically regarded as having a lower acid content than conventional drip coffee. This is so that the acids can be extracted more quickly. Hot water is pumped swiftly through the coffee grinds. Additionally, darker roasts, which have less acidity than lighter roasts, are frequently used to make espresso. However, the type of coffee beans used, the degree of roasting, and the brewing technique can all affect how acidic coffee or espresso actually is.