Definition: Supra-extraction

A modern process for increasing the sugar content of grapes in wine, without chaptalisation. It involves removing some of the water contained in the berries by cooling the grapes. This technique, inspired by German ice wines (Eiswein), involves cooling the grapes stored on racks in a ventilated cold room to minus five degrees Celsius. This transforms the least sugar-rich part of the grape into ice. Then, eight to twelve hours later, the grapes are pressed very gently to extract only the sugar-rich juice that has not been transformed into ice. This method produces a concentrated must similar to that obtained from grapes selected through successive sorting of the ripest berries. This treatment results in greater concentration and aromatic intensity. Many estates producing sweet wines are equipped with these expensive facilities, enabling them to produce a higher quality must even in rainy years or when ripeness is insufficient. However, this technique involves additional handling, with a significantly reduced yield (30 to 40%) when pressing the grapes (see also cryoextraction).