SOStain is a proactive and voluntary program based on a four-step quality model – which is a continuous improvement cycle. Assessment over time is the key element of this self-improvement model. The model is designed to ensure confidentiality, extensive participation and collective progress along the continuum of sustainability.

The cycle illustrates the process-based view of sustainable wine production, and consists of self-assessment, the interpretation of performance, action planning and the implementation of change. Sustainable wine production is a process of repeated appraisal and sensible progress consistent with site-specific constraints and circumstances.