Śatapatha Brāhmaṇa ("of a hundred paths") 3.6.2.19

3.6.2.19

tatheti devā abruvan | somakrayaṇā va iti tānebhya etatsomakrayaṇānanudiśatyathainānabruvaṃstṛtīyasavane vo ghṛtyāhutiḥ prāpsyati na saumyāpahṛto hi yuṣmatsomapīthastena somāhutiṃ nārhatheti saināneṣā tṛtīyasavana eva ghṛtyāhutiḥ prāpnoti na saumyā yacālākairdhiṣṇyānvyāghārayati

The gods spake, 'So be it!' By saying, '(Here are) your Soma-wages...' he assigns to them the price of the Soma. They then said unto them, 'At the third pressing an offering of ghee shall fall to your share, but not one of Soma, for the Soma-draught has been taken from you, wherefore ye are not worthy of a Soma-offering!' And accordingly, when he pours ghee on the hearths by means of fagots, at the evening libation, that same offering of ghee falls to their share, but not one of Soma.