This Research Paper addresses the hypothesis that the type of dulce de leche formula affects formation of 5-hydroxymethylfurfural (HMF) during production and storage. Milk and sweetened condensed milk are products in which the Maillard reaction (MR) defines important characteristics such as colour and taste. There are few studies on the effects of pH, time, concentration, and sugar type on the formation of HMF or other MR markers in DL. Four formulas (varying in the addition of sodium bicarbonate and the type of sugar) were analysed for moisture, lipid, protein, ash, carbohydrate, water activity (Aw), and soluble solids. We found low variability in physicochemical and compositional attributes, but an elevation of HMF indices throughout the manufacturing. We determined that the addition of glucose and the use of relatively high concentrations of sodium bicarbonate caused these HMF indicator increases. These results inform DL research and production by the dairy industries and the scientific community, and highlight the importance of control in manufacturing.