The phenomenon of mutarotation appears to be due to the changes of α- and β-forms and vice versa via the straight chain aldo to keto form. It is generally accepted that the mechanism of mutarotation involves opening and closing of the hemiacetal ring structure of monosaccharides to form traces of aldehyde and α- to β-ring forms. When equilibrium is attained, the characteristic rotation is reached. All monosaccharides exist in three forms in nature, namely aldehyde form, α-ring form, and β-ring form.

Of the three forms, the aldehyde form is said to extremely unstable and exists only as a transient intermediate. According to Lowry (1925), mutarotation can take place only in the presence of an amphiprotic solvent (i.e. a solvent that can act as both an acid and a base). Water is one such solvent.