It was a custom among the ancient Hindus to offer newly harvested grains to the Vedic deities before consuming them. Āgrayaṇa is an agricultural rite of the iṣṭi type (See IṢṬI for details.) which an āhitāgni (one who has ceremonially established the Vedic fires) should perform, before making use of the newly harvested grains. The rite was considered necessary only with regard to vrīhi (rice), yava (barley) and śyāmāka (a kind of yellow grain, Panicum frumentaceum) and not for other grains, vegetables or fruits. Oblations of cooked food are offered to the deities like Indra and Agni. A lump of the cooked food should be thrown on the top of the dwelling house. The sacrificer should also eat a mouthful of the grain.
Even those who have not established the Vedic fires can perform Āgrayaṇa in the aupāsanāgni (domestic fire lighted at the time of marriage) with an extra oblation to Agni-sviṣṭakṛt.
This rite is also called Navayajña or Navasasyeṣṭi.