Hiranyakeshigrihyasutra 1.2.7.21

1.2.7.21

eteṣāmevānnānāṃ samavadāya prāgagreṣu darbheṣu baliṃ karoti \ vāstupataye svāhā \ iti \21\

When the food (with which the Brâhmanas shall be entertained) is ready, (the student) takes some portion of boiled rice, cakes, and flour, mixes (these substances) with clarified butter, and sacrifices with (the formulas), 'To Agni svâhâ! To Soma svâhâ! To Agni, the eater of food, svâhâ! To Agni, the lord of food, svâhâ! To Pragâpati svâhâ! To the Visve devâs svâhâ! To all deities svâhâ! To Agni Svishtakrit svâhâ!'