• 酉(wine vessel; ferment)
• 夋(slow manner; leisurely pace)

Fermenting alcohol produces sourness, which is exactly the character for sour.

• 女(woman; female)
• 乃(then; also (suggests 'nãi'))

Grandmother and mother's milk attach to the woman radical, sounding like "nãi" similar to the character 乃.

• 氵(water; liquid)
• 由(from; due to; oil (phonetic))

Oil is a liquid that flows from a natural source.

• 酉(wine vessel; ferment)
• 夋(slow manner; leisurely pace)

Fermenting alcohol produces sourness, which is exactly the character for sour.

• 女(woman; female)
• 乃(then; also (suggests 'nãi'))

Grandmother and mother's milk attach to the woman radical, sounding like "nãi" similar to the character 乃.

• 氵(water; liquid)
• 由(from; due to; oil (phonetic))

Oil is a liquid that flows from a natural source.