Input lever
Flow, Pressure & Separation
Detail panel
Press force
The physical force applied to the plunger.
AeroPress Wheel Variable
Permeability change
Flow, Pressure & Separation · Process state
How the bed’s flow openness changes during pressing.
Process state
Flow, Pressure & Separation
Advanced detail
Technical science
Inferred
Definition
Permeability change captures the dynamic way the bed becomes more or less restrictive as the press progresses.
Why It Matters
It explains why pressing often slows down even under similar applied force.
Page Context
Permeability change is part of the Brew Supply AeroPress Wheel and helps brewers describe how the bed’s flow openness changes during pressing.
Related variables
Input lever
Flow, Pressure & Separation
Wheel face
Plunger speed
How quickly the plunger moves downward.
Input lever
Flow, Pressure & Separation
Wheel face
Output flow rate target
The desired liquid output speed during pressing.
Input lever
Flow, Pressure & Separation
Wheel face
Press duration
How long the active press phase takes.
Input lever
Flow, Pressure & Separation
Advanced detail
Pressure ramp
How pressure builds during the press.
Input lever
Flow, Pressure & Separation
Detail panel
Stop depth
The physical plunger position where pressing stops.
Affected outcomes
Measured metric
Cup Outcome
Wheel face
Beverage TDS
Measured total dissolved solids in the served beverage.
Calculated metric
Cup Outcome
Wheel face
Extraction Yield
Calculated percentage of coffee mass extracted.
Measured metric
Cup Outcome
Wheel face
Beverage Yield
The liquid beverage mass collected or served.
Cup outcome
Cup Outcome
Wheel face
Aroma
The smell of the brewed coffee.