Flash Détente (détente is the French for relaxation or depressurization), or Thermo Flash, is a technique developed in Europe over 20 years ago that is one of a number of thermal treatments. Since 2009, Flash Detente has been available in California with 6 installations which have crushed over 100,000 tons.
The process consists of heating grapes to a high temperature (175-185 F), them immediately pumping the fruit into a vacuum chamber. Once in the vacuum chamber, some of the water associated with the must, evaporates or “flashes” immediately into steam. This depressurization causes the vacuoles in the grapes skins to explode, releasing the tannins and color they contain. This release of the color and structure in many ways replaces the more traditional maceration of punching down or pumping over. Flashed wines often have, on average, about 30% greater color and structure.
Additionally, the steam which flashes off of the grapes is condensed. This flash water is enriched in some grape volatiles, particularly pyrazine. The water can be discarded resulting in a grape must which is essentially free of vegetal character. It is this application of flash that has led to its widespread adoption in California. Flash may also be a good procedure to reduce aromas from smoke taint or other unwanted characters.
- Elimination of Pyrazine and Vegetal Character
- Mitigation of Smoke Taint in Grapes
- Ability to Barrel Ferment Red Grapes
- Elimination of Laccase, Mold or Unripe Flavors