Ashtangasamgraha 17.38

17.38

rasaṃ vidyānnipātena tenādhivasanena ca |

vīryaṃ vipākaṃ dravyāṇāṃ karmaṇaḥ pariniṣṭhayā ||

sraṃsanāni cānnānyudāvartaharāṇi ca tīkṣṇaṃ ca virecanaṃ yacca kiñcidvātaghnam ||

One should know taste by contact [with the tongue], and by its remaining [in the mouth];
potency and post-digestive effect of substances [are known] through the final outcome of the action.

And laxative foods, removers of upward movement of vāyu, sharp purgatives, and whatever relieves vāta [should be given].