What Has the Biggest Impact on Espresso Crema?

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.