Flow-regulated extractions

What is Flow Regulation?

• Instead of controlling pressure, barista controls the flow rate of water entering the puck (e.g., 2–6 ml/sec).
• Common in modern machines with flow control valves or needle valves.
• Goal: Maintain predictable puck saturation and extraction speed.

Key Characteristics

• Consistency: More direct control over how fast water moves through puck.
• Adaptability: Helps manage different roast levels, doses, and grind settings.
• Gentle Extraction: Avoids channeling by ensuring uniform wetting.

Typical Flow Profiles

1. Low Initial Flow (Prewetting): 1–2 ml/sec for 5–10 sec → gentle saturation.
2. Ramp-Up Phase: Increase to 3–5 ml/sec → active extraction.
3. Tapered Finish: Reduce to 2–3 ml/sec → prevents over-extraction in late phase.

Benefits

• Reduces risk of channelling by preventing sudden pressure spikes.
• Produces cleaner, sweeter cups with light roasts.
• Improves repeatability when dialing in new coffees.

Challenges

• Requires more barista skill and attention.
• Slower workflow if flow is too restricted.
• Machines with adjustable flow are less common and more expensive.

Example Workflow

• Dose: 18 g, grind medium-fine.
• Start: 2 ml/sec for 8 sec prewetting.
• Main: 4 ml/sec until 36 g yield.
• Finish: taper to 3 ml/sec.
• Result: Sweet, balanced, with reduced bitterness.

Summary

Flow-regulated extractions shift focus from pressure to water flow, allowing baristas to fine-tune saturation and extraction pace. This technique enhances clarity, reduces channeling, and is especially powerful for lighter roasts, though it demands precise technique and advanced equipment.

• Tags:
• Flow Rate
• Light Roasts
• Fine Tune
• Roast Levels
• Water Flow
• Lighter Roasts
• Challenges Requires
• Reduces Channeling
• Medium Fine
• Reduces Risk
• Example Workflow
• Sweet Balanced
• Dose Grind
• Flow Control
• Grind Settings
• Different Roast
• Reduced Bitterness
• Modern Machines
• Produces Cleaner