Subye, a traditional beverage of Turkey, is produced from melon seeds, sugar, and water. The standard production protocol for Subye beverage includes mixing minced rehydrated melon seed mass with sugar to obtain Subye paste in the ratio of 1:1.125 (w/w), respectively, and mixing 25% of the paste with water. The total moisture, sugar, fat, protein, and ash contents of the standardized beverage were found to be 84.24%, 11.65%, 1.52%, 1.35%, and 0.21%, respectively. A 99% suspension stability of the beverage was achieved after one day of storage by addition of a xanthan gum:guar gum combination (0.04%: 0.5% and 0.05%: 0.4%). No significant differences (p > 0.05) were found between the gum-containing samples and control samples for the Hunter color values and for the sensory characteristics, such as mouthfeel, taste, and overall acceptability (except for appearance). Nisin: natamycin (2 ppb:30 ppm) was statistically found to be the most effective antimicrobial combination for aerobic mesophilic bacteria after storage for 6 days. Nisin: natamycin (2 ppb:30 ppm) and nisin: potassium sorbate (2 ppb:250 ppm) combinations were found the most effective antimicrobial combinations for mold and yeast count after storage for 3 days and 6 days, respectively.