Utilizing more than one sweetener has been shown to be an effective way to substitute sucrose in food products. The objective of this study was to apply the augmented simplex-centroid mixture design for the optimization of acceptable sweetener blends using coconut sugar, agave, and stevia. Sweetener blends were evaluated in aqueous solutions and gluten-free granola bars by a trained panel and consumers (n = 60). Significant differences were found between sweetener mixtures in solutions by both panelists and consumers (P < 0.05). Taste profiles for the sweetener solutions were also generated using the electronic tongue. Most consumer and trained intensity ratings were highly correlated (R(2) ≥ 0.79) with the electronic tongue taste profile analysis. Granola bars were also found to be significantly different (P < 0.05), with consumers preferring coconut sugar mixtures. Using contour plots and desirability function analysis, an optimal sweetener combination was found for a granola bar formulation of 89.9% coconut sugar, 6.1% agave, and 4% stevia. These results indicate that a mixture design can be a reliable way to develop new sweetener blends for product development.