What You Need to Know
The process involves evaporating water at 80–90 °C, concentrating sugars from ~10 % to ~20 % w/w, lowering water activity to ~0.8, while maintaining tartaric and malic acids and oxidizing phenolics to increase antioxidant activity. Careful temperature control prevents caramelization (~150 °C) and volatile acid loss.
The Science
Primary Reaction
Evaporation of water (reduction) and mild oxidation of phenolic compounds