The quality of the raw material for chocolate manufacture depends on the control of cacao seed fermentation. Practices affect the diversity and metabolic activities of spontaneous yeasts in fermentations. The control of the initial inoculum is important to standardize fermentations and to improve the final seed quality. We conducted fermentations using non-cleaned or cleaned fermentation boxes to evaluate the dynamics of the microorganism populations and their effect in seed composition in two consecutive years. The isolated yeasts were identified by sequencing the D1-domain of the 26S ribosomal genes. Pulp and cotyledon parameters were monitored during fermentations. Wickerhamomyces anomalus was the dominant yeast in the fermentations, but the species was less represented in cleaned boxes. In the cleaned-box fermentation, there was a delay in temperature rise of the fermentation, which retarded the suitable moment for seed-mass turning. The reduction in seed-pulp quality caused by restricted rainfall in one year limited the seed-mass heating and voided the seed turning. Thus, under substrate restriction, the initial reduced inoculum caused by cleaning the boxes impaired fermentation, mainly under environmental conditions that compromise the quality of the pulp. However, this variation had little effect on the desired degradation of cotyledon components, substrates for flavor precursors.