Tarac Environment Future Fund:	2006
Project:	Economical lees management strategies
Fund recipient:	Provisor Pty Ltd

The project investigated the application of surfactants/enzymes to improve the flow properties of fermentation lees and the opportunities for improvement in lees management.

As part of the research a literature review was undertaken to collate existing knowledge about yeasts, surfactants, enzymes and rheology measurements. Consultation with technical experts was also conducted to identify commercially available surfactants/enzymes and determine their suitability for application to fermentation lees. This culminated in laboratory investigations to evaluate a range of surfactants/enzymes identified, and gather effective proof-of-performance data.

Lees were provided by Orlando Wyndham Wines with a solids composition of 23%.

Results indicated that:

• Viscosity reduction was possible with a wide range of anionic, cationic and non-ionic surfactants.
• Tergitol L-62 was chosen for further testing because it was biodegradable, had FDA approval and was easy to use.
• Lees viscosity was decreased by 20% through agitation or addition of Tergitol L-62 at 0.5%w/w level.
• Settling rate also increased with the addition of Tergitol L-62.
• Tergitol L-62 however had an adverse impact on the sensory qualities of wine.

This preliminary research opens up possibilities for further investigations in this area.