Grape berries under high voltage
Established processes in making red wine are mash fermentation (non-thermal hydro-alcoholic extraction) and mash heating (thermal aqueous extraction). Both processes serve to extract from the skins of the grape berries pigments and tannins.
State of the art
Although mash heating takes only a very short processing time, it may cause a slight impairment of flavor (adding a marmalade-like so-called cooking flavor). This poses the problem to the wine industry to open up grapes and grape berries in the mildest way possible and make their valuable contents accessible to extraction and diffusion.
KIT scientists at the Institute for High-power Impulse and Microwave Technologies (IHM), in cooperation with the State Institute of Viticulture in Freiburg, developed a technical process which extracts the contents of grape berries effectively, softly and, at the same time, quickly. This is a non-thermal aqueous extraction method which works without heating of the material to be processed and takes an extraction time of only a few hours.In the course of their research and development work, the KIT scientists installed a cell extraction reactor with a plate-shaped electrode geometry in the existing Karlsruhe Electroporation Facility (KEA). For cell extraction, the mash passes through a reaction zone in which it is exposed to a pulsed near-homogeneous electric field. Exposing the mash to a number of very short high-voltage impulses causes the pores especially in the membranes of the cells of the grape berry skins to be opened irreversibly. Valuable contents, such as pigments, tannins and aromas, in this way are made accessible to efficient extraction at ambient temperature.
The so-called "mash poration" can be used in red wine production both as an alternative to mash heating and as a support in mash fermentation and white must production. Besides technical process advantages, such as reduced down times and processing times and lower energy costs, the efficient digestion of grape berries improves wine quality.
Options for companies
The KIT is looking for industrial partners to commercialize the process.
Your contact person for this offer
Dr.-Ing. Philipp Scherer,
Karlsruhe Institute of Technology (KIT)
Innovation Manager Mobility, Innovation and Relations Management (IRM)
Phone: +49 721 608-28460