Crema

Crema forms when pressurized water (typically 9 bars) forces CO₂ out of freshly ground coffee and emulsifies it with lipids and surfactant proteins. Fresh-roasted coffee (3–14 days post-roast) produces the most crema; stale beans yield thin, pale foam. While crema is often seen as a quality indicator, its taste is actually quite bitter and astringent on its own. Some competition baristas deliberately stir or skim crema to achieve a more balanced cup. Robusta beans produce significantly more crema than Arabica due to higher CO₂ generation during roasting.