Bed depth and flow stability
How the depth of the coffee bed in filter brewing impacts flow stability, extraction balance, and flavor outcome.
- Coffee Basics Nerds
- 1 min read
Bed Depth and Flow Dynamics
-
Shallow Beds:
-
Occur with low doses or wide brewers.
-
Water flows quickly, reducing contact time.
-
Risks: under-extraction, sour flavors, and reduced body.
-
Deep Beds:
-
Created with higher doses or narrow brewers.
-
Increase resistance, slowing flow and extending contact time.
-
Risks: over-extraction, bitterness, or stalling if grind is too fine.
-
Flow Stability:
-
Even bed depth ensures predictable drawdown.
-
Inconsistent depth across brews can cause variations in cup quality.
-
Channeling is more likely in unevenly leveled or disturbed beds.
-
Practical Brewing Guidelines:
-
Optimal bed depth is typically 2–4 cm for pour-over devices like V60 or Kalita.
-
Level grounds before brewing by gentle shaking or tapping.
-
Match grind size to bed depth: shallower beds may need finer grinds, deeper beds slightly coarser.
-
Flavor Outcomes:
-
Shallower beds → lighter, brighter cups with more clarity but less body.
-
Deeper beds → heavier, fuller-bodied brews, but clarity may reduce.
Summary
Bed depth is a critical but often overlooked variable in filter brewing. Maintaining consistent depth and matching grind appropriately ensures stable flow, balanced extraction, and reproducible flavor profiles.