The Crema Myth: Dark vs. Light Roast

Roasting’s Role

Contrary to common belief, dark roast coffee doesn’t always lead to more crema than its light roast counterpart. The intense heat and longer roast times of dark beans generate more carbon dioxide. This might create a bolder initial crema, but it tends to fade quickly.

Factors Affecting Crema

Roasting process:

During the roasting process, coffee beans undergo chemical reactions, which cause them to release gases, mainly carbon dioxide (CO2). Darker roasts are exposed to higher temperatures and longer roasting times, causing more CO2 to be generated. This increased CO2 release can lead to a more significant initial volume of crema, but the effect might not last as the crema could dissipate more quickly.

Bean density and solubles

Dark roasts have a lower density than light roasts because they lose more moisture during roasting. As a result, dark roasts can release more soluble compounds during the brewing process, which could contribute to a more noticeable crema. However, this does not necessarily mean that the crema is more abundant or thicker, just that the color and texture might be different.

Oil content

Darker roasted beans have more oils on their surface than lighter roasted beans, as the oils are extracted from the beans’ interior during the roasting process. These oils can contribute to the formation and appearance of crema. However, they can also make the crema less stable, causing it to dissipate more quickly.

Age of the beans

The freshness of coffee beans also affects crema production. As beans age, they release CO2, which is essential for crema formation. If dark roast beans are not used soon after roasting, the crema may be less abundant and less stable than that of a fresh light roast. On the other hand, light roast beans typically retain more CO2 for a more extended period, which can help produce a more stable and longer-lasting crema.

In conclusion, darker roasted coffee might produce a more noticeable crema initially due to the higher CO2 release, oil content, and more soluble compounds. However, this doesn’t necessarily mean that darker roasts produce more crema or a better-quality crema than light roasts. The crema’s quality, stability, and volume depend on various factors, including the type of coffee, roast level and freshness.