दध्नः सोम्य मथ्यमानस्य योऽणिमा स उर्ध्वः समुदीषति तत्सर्पिर्भवति ॥ ६.६.१ ॥
In plain words
Of curds that are churned, my dear, the finest part rises upward and becomes butter.
The commentators
Chāndogyopaniṣadbhāṣyam· bhāṣya
दध्नः सोम्य मथ्यमानम्य योऽणिमा अणुभावः स ऊर्ध्वः समुदीषति संभूयोर्ध्वं नवनीतभावेन गच्छति, तत्सर्पिर्भवति ॥
In plain words
When curd is being churned, my dear, that subtle, microscopic essence rises upward, gathers together at the top in the form of fresh butter, and turns into butter.
Close to the Sanskrit
Of curd, my dear, being churned, whichever is the subtlety, the atomic state, that rising upward, coming together upward in the state of fresh butter, goes, that becomes butter.