Catalyzes the 3-beta-hydroxylation of (2S)-flavanones to 2R,3R-dihydroflavonols, which are intermediates in the biosynthesis of flavonols, anthocyanidins, catechins and proanthocyanidins in plants (PubMed:31004005). Can act on naringenin to produce dihydrokaempferol, and on eriodictyol to produced dihydroquercetin (PubMed:31004005). 2-oxoglutarate + a (2S)-flavan-4-one + O2 = a (2R,3R)-dihydroflavonol + CO2 + succinate (2S)-naringenin + 2-oxoglutarate + O2 = (2R,3R)-dihydrokaempferol + CO2 + succinate (S)-eriodictyol + 2-oxoglutarate + O2 = (2R,3R)-dihydroquercetin + CO2 + succinate Binds 1 ascorbate molecule per subunit. Binds 1 Fe(2+) ion per subunit. Flavonoid metabolism. Expressed in young cromes. Belongs to the iron/ascorbate-dependent oxidoreductase family.