Think of separating wheat from chaff. 'Winnow out' involves a selection process that keeps the best.

Selective Filtering

'Winnow out' implies a focus on quality by discarding the less desirable.

Quality Emphasis

The phrase suggests cutting down on quantity to improve quality or efficiency.

'Winnow out' refers to uncovering something hidden within a larger group.

It suggests using analytical skills to find and identify specific items or facts.

Implies a challenge in isolating the subject of interest from everything else.