Degassing and CO2 curves

What is Degassing?

• During roasting, coffee beans undergo pyrolysis, generating carbon dioxide (CO₂).
• After roasting, beans gradually release CO₂—a process called degassing.
• Degassing affects freshness, brewing performance, and flavor development.

The CO₂ Curve

• Rapid Phase: First 24–72 hours → ~40–50% of CO₂ escapes.
• Slower Phase: Next 1–3 weeks → gradual decline.
• Stable Phase: After ~4–6 weeks, most CO₂ is gone; beans risk staling from oxygen exposure.

Why Degassing Matters

1. Brewing Quality:

• Too much CO₂ → uneven extraction, excessive blooming, foamy espresso crema.
• Too little CO₂ → flat, stale flavor.

2. Packaging:

• Coffee bags use one-way valves to allow CO₂ out while preventing oxygen in.

3. Freshness Indicators:

• Bloom in pour-over or crema in espresso can signal degassing stage.

Practical Guidelines

• Resting Periods:
• Espresso: 5–14 days post-roast (balance crema and flavor).
• Filter: 2–7 days post-roast (reduce excess bloom).
• Storage: Airtight, cool, dry, away from light.
• Batch Planning: Roast dates should align with ideal resting periods for brewing method.

Visualizing CO₂ Curves

• Curves typically show a steep initial drop, then a long, shallow decline.
• Useful for roasters to anticipate shelf life and recommend optimal brew windows.

Summary

Coffee beans release CO₂ along a degassing curve, with rapid release in the first days and slower decline afterward. Managing degassing ensures optimal brew performance, flavor expression, and freshness—making CO₂ awareness key to storage and brewing strategy.

• Tags:
• Shelf Life
• Coffee Beans
• Summary Coffee
• Uneven Extraction
• Post Roast
• Flavor Development
• Cool Dry
• Brewing Method
• Espresso Crema
• Oxygen Exposure
• Carbon Dioxide
• Flavor Expression