Substrate consumption, ethanol production, microbial growth, and temperature increase in a fermentation vessel are metabolically interrelated biological phenomena. In spontaneous wine fermentations, mixed cultures of various microbial species are involved in the fermentation process. Due to the continuously changing species contributing to the microbial population, these metabolically interrelated parameters are treated separately in the enology literature. In the present study, mathematical models are presented to interrelate these parameters, by employing the data obtained from a totally uncontrolled spontaneous wine production process. Ethanol production rates were related to biomass production with a modified Luedeking-Pirect equation. In the ethanol production phase of the process, total microbial growth did not slow down with ethanol accumulation. This might be caused by the compensating effects of temperature increase. Ethanol production yield of the culture increased with ethanol accumulation in the medium, possibly due to elimination of the low-alcohol-tolerant, poor alcohol-producing species. Microbial growth was simulated with the logistic equation in the malo-lactic fermentation phase.