What You Need to Know
During reduction, water evaporates, raising sugar concentration from ~10 % to ~30 % w/w, which increases viscosity and lowers water activity to ~0.8, inhibiting microbial growth. The acid content rises proportionally, lowering pH to ~3.5–4.0 and stabilizing color. Temperatures above 100 °C can caramelize sugars and degrade tartaric acid, altering flavor.
The Science
Primary Reaction
Evaporation of water from pomegranate juice, concentrating sugars and acids.