A Complete Breakdown of Random Variables in Pour-Over Coffee

Why do people call pour-over coffee “unpredictable”?
Why can V60, Origami, or Kalita Wave produce completely different results with the same beans and recipe?

The truth is simple:
Pour-over coffee has too many invisible variables.

At Vihi, we turn these unknowns into measurable engineering structures.

01｜Filter Paper Variables

filter paper, kalita wave, v60 filter, paper thickness

• Angle inconsistency (especially Wave filters)
• Paper thickness variations
• Fiber density differences
• Deformation from stacking/transport

These directly affect:

• Flow rate
• Bypass
• Bed geometry

This is why V-Fold 38.3° exists — to eliminate paper randomness.

02｜Flow Rate Variables

flow rate, turbulence, bypass, dripper geometry

• Wall-side flow is always faster
• Center flow is slower
• Turbulence varies with pouring height
• Asymmetry due to pouring direction

Every pour is a different extraction.

03｜Grind Variables (Fines)

fines, grind size distribution, unimodal, burr design

Most inconsistency comes from fluctuations in fines generation.

Traditional hoppers force beans to compress each other, creating fines.

G-Flow solves this with:

• Motor-driven rotating disc
• Slow-feed geometric channel
• True single-bean/small-dose feeding

Resulting in cleaner, smoother extractions.

04｜Bed Geometry Variables

bed shape, cone dripper, flat-bottom dripper

Different drippers = different extraction physics.

• V60 — deep bed, vertical flow
• Origami — prone to ring bypass
• Kalita Wave — stable, shallow bed

05｜Pouring Technique Variables

turbulence, pulse pouring, continuous pour, blooming

• Pouring height
• Flow rate
• Circle size
• Pulse vs continuous
• Blooming duration

Every small motion creates a different extraction curve.

06｜Why Pour-Over Feels “Unpredictable”

Because it contains:

• Filter paper variance
• Flow rate variance
• Fines variance
• Bed geometry variance
• Pouring technique variance

07｜Vihi’s Mission: Turning Randomness Into Engineering

• V-Fold — eliminates paper inconsistency
• G-Flow — reduces fines, stabilizes grinding
• Future — engineering-based dripper systems

We engineer the parts of coffee that people once thought were unpredictable.

This is the value of Vihi.