2 adjectives to describe winnowing

Thought on burning thought Shatters the doubts and terrors which have bowed Weak hearts on weaker leaning in a crowd Self-crushing and self-fettering; gleams are caught From some far centre set by God to keep His brave world spinning, or some drifting isle Of swift wildfire shot out by the wide sweep Of wings demoniac, Far winnowing and black, Our cheated souls to 'wilder and beguile.

His vigorous winnowing sent chaff to the winds, but not without some scattering of wheat.

2 adjectives to describe  winnowing