In this work we aimed to investigate the source of the Red Globe grape skin pigmentation. To achieve this goal, we used the phase-resolved photoacoustic technique to investigate the sample in natura and to access the phase-dependent absorbing entities. In addition, we used the time-dependent density functional theory (TDDFT) to contrast with our experimental spectroscopic results. We measured the absorption spectrum of the Red Globe grape in natura using the photoacoustic technique and recovered the main source pigmentation spectrum using the phase-resolved technique. Finally, using the TDDFT, we qualitatively analyzed the physical sources of the grape pigmentation and we found significant evidence that the main biomolecules responsible for the coloration of the grape are the cyanidin-3-O-glucoside and the peonidin-3-O-glucoside.