A Technology Feature Article
Technology: Rotary Drum Vacuum Filtration
Type: Filtration & Membrane Technologies
For Improved Colour & Structure in Red Wines
An evolution of thermovinification for red wines, in flash détente, de-stemmed grapes are heated to 80-85 ᵒC then immediately pumped into a vacuum chamber where flash vaporisation of water inside the vacuoles of the grapes skins, causes them to explode, releasing all the pigments contained within, while avoiding the jammy characteristics of thermovinified wines.The Flash Détente process was originally patented in 1993 by INRA, the French National Institute for Agricultural Research, where the complete release of colour precursors replaces traditional maceration. Flashed wines have on average, 30% more colour and improved structure and experience shows a lift in sugar concentration of around two Brix after flash-détente.
Further, isobutyl-methoxypyrazine (IBMP) is a compound associated with ‘green capsicum’, ‘herbaceous’ and ‘tomato leaf’ aromas and has a boiling point of 50°C at atmospheric pressure (Roujou de Boubée 2003). Flash détente is particularly effective in reducing ‘green’ characters as the methoxypyrazine is collected in the condensate. C6 compounds that can also be responsible for ‘green’ aromas are also lowered, as heat denatures enzymes associated with the production of C6 compounds (Fischer et al. 2000).
In addition, the minimised skin contact resulting from Flash Détente helps to eliminate laccase from botrytis and other unwanted characteristics.
After Flash Détente processing, the must is sterile and ready to be inoculated for fermentation. It can even be pressed immediately, allowing the juice to be fermented off-skins as with white wine. In most cases, the juice or wine resulting from Flash-Détente treatment are used as a blending component.
- The complete release of colour precursors, thus replacing traditional maceration. Flashed wines have on average, 30% more colour and improved structure.
- The vapour which flashes from the grapes carries away undesirable grape volatiles, including vegetal methoxypyrazine.
- An increase of approximately 2° Brix in sugar content post Flash Détente.
- Extraction of colour and phenolics while minimizing skin contact, eliminating smoke taint, laccase from botrytis or other unwanted characteristics from deposited environmental factors.
- Sterile must, ready to be inoculated.
- Must that can be pressed and fermented off skins as with white wine, to conserve tank space.
- Rapid fermentation with no maceration time required.
To learn more about using Flash Detente this harvest, please contact your Vintech Pacific regional office.