Recovering Higher Value Wine and Juice from Lees
Recovery of wine and juice from lees represents one of the most challenging forms of filtration faced by wineries. The high concentration and variability of the suspended solids limits the suitable filtration technologies, while strict environmental regulations and sustainability programs are increasing pressure to reduce waste volumes. The Oenoflow HS system is a new crossflow filtration system designed specifically for lees processing. The hollow fiber membrane system overcomes the typical drawbacks associated with the existing Diatomaceous Earth (DE) based lees filters, producing higher quality product more efficiently and economically.
The Lees Challenge
Lees, the sediment at the bottom of juice, fermentation or fining vessels, can represent up to 10% of a winery’s total volume. With solids concentrations typically in the range of 20 –30%, lees still contains a high percentage of recoverable product.
Traditionally, lees filtration is performed with DE based filtration systems like rotary vacuum drum (RVD) or chamber press filters. While these systems can handle high solids, the open design allows for oxygen pick up which can affect quality. Recovered wine often needs further processing, and is typically downgraded in value and used in blends instead of added back to the original batch. In many small and mid size wineries, the lees volume from a single batch is often too small for processing with an RVD. In such cases the wineries will delay processing the lees and wait to accumulate an appropriate volume, hence the potential to recover high value product is lost.
DE based technologies can also require large volumes of filter aid. This increases the winery waste, disposal, labor, and losses; all factors contributing to high operating costs.
The Oenoflow HS system is a new crossflow filtration system for lees filtration that overcomes many of the obstacles associated with the traditional DE based technologies. Filtration is achieved with microporous membranes without the need for filter aids. With no powder handling, operation is more hygienic and does not create DE waste for environmental landfill.