The Compendium of Caraka 1.26.40

1.26.40

teṣāṃ ṣaṇṇāṃ rasānāṃ somaguṇātirekānmadhuro rasaḥ pṛthivyagnibhūyiṣṭhatvādamlaḥ salilāgnibhūyiṣṭhatvāllavaṇaḥ vāyvagunibhūyiṣṭhatvāt kaṭukaḥ vāyvākāśātiriktatvāttiktaḥ pavanapṛthivīvyatirekāt kaṣāya iti /

Among those six tastes, sweet taste arises from the predominance of the lunar quality; sour from the abundance of earth and fire; salty from the abundance of water and fire; pungent from the abundance of wind and fire; bitter from the excess of wind and ether; and astringent from the preponderance of wind and earth.