Data for the article: Modeling the Formulation pH of Elderberry Syrup with multiple weak acids, https://doi.org/10.1111/1750-3841.16664. To develop methods to assess the influence of the ingredients of an acidified elderberry syrup on product pH., a total of 16 model syrup formulations containing elderberry juice with mixed acids (malic, acetic, and ascorbic) and having pH values between 3 and 4 were prepared. The pH values of the formulations were compared to predicted values from combined buffer models of the individual ingredients. Regression analysis indicated an excellent fit of the observed and predicted pH data, with a root mean square error of 0.076 pH units. The results indicated that buffer models may be useful for in silico estimates of how the ingredients in acid and acidified foods may influence pH, thus aiding in product development and safety assessments.