Crema is the golden foam on top of espresso, created when pressurised carbon dioxide and oils emulsify during extraction. While many variables play a role, some matter far more than others.
Biggest Influences on Crema (Ranked)
1. Bean Freshness (Age of Coffee Beans) — ≈30–35%
The most important factor.
Freshly roasted beans contain more CO₂
As beans age, CO₂ escapes → less crema
Best window for crema: 7–21 days post-roast
Old beans = thin or no crema, regardless of technique.
2. Coffee Bean Type (Arabica vs Robusta) — ≈20–25%
Robusta naturally produces more crema.
Robusta → thicker, more persistent crema
Arabica → finer, lighter crema
Many espresso blends include Robusta specifically for crema.
3. Roast Level — ≈15–18%
Roast affects gas retention and oil release.
Medium to medium-dark roasts produce the most stable crema
Very dark roasts lose CO₂ faster
Very light roasts can produce less visible crema
4. Grind Size & Extraction — ≈10–12%
Controls pressure resistance.
Too coarse → weak crema
Too fine → unstable or over-extracted crema
Proper grind allows CO₂ to emulsify with oils.
5. Pressure (Espresso Machine) — ≈8–10%
Crema requires pressure.
Ideal extraction pressure ≈ 9 bar
Too low → little crema
Too high → foamy, unstable crema
6. Dose & Brew Ratio — ≈5–7%
Affects crema volume and density.
Higher dose → more crema
Incorrect ratio → thin or uneven crema
7. Water Temperature — ≈3–5%
A secondary factor.
Too hot → breaks down crema
Too cool → poor emulsification
8. Bean Oils & Processing Method — ≈2–4%
Minor but noticeable.
Natural / honey-processed coffees can boost crema
Very clean washed coffees may produce less
Key Takeaway
Crema is driven mainly by freshness, bean type, and roast — not the espresso machine.
Around 65–70% of crema formation is determined before brewing even begins.