Wine glossary

reverse osmosis, vacuum evapouration
Definition:methods used to draw water out of the must, must concentration

This is a wine-making operation used to increase the concentration of the must, whereby water and grape juice is drawn out of the must. In a vacuum, water begins to evapourate at 25°C to 30°C, without having any negative effect on the aromas of the finished wine. This form of concentration has been permitted in the EU for a number of years, and is already a practice employed in Austria as an alterative to chaptalization in red wine production. Vacuum evapouration is also a process used for the production of alcohol-free wine.