Recovery of wine and juice from lees is a challenging yet unavoidable task for wineries worldwide. The high concentration and variability of the solids make filtration difficult; however, with the lees comprising up to 10% of a winery's total production volume, there is still a high percentage of recoverable wine and juice. Lees filtration is typically carried out using rotary vacuum drum (RVD) filters or chamber press filters. While these systems can handle the high solids, the open design allows for high oxygen pick up, which can negatively impact the product quality. The recovered wine or juice is often downgraded in value and used in lower-tier blends instead of being added to the original batch. The existing technologies can also require high volumes of filter aids like diatomaceous earth (DE) or perlite, which increase the wineries' waste generation and disposal requirements and contribute to high operational costs.
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Challenge
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Solution
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Benefits
With a decreasing global wine surplus, higher prices for bulk wine and increasing competition, wineries are under pressure to increase yield and improve quality. With new legislation, they must also satisfy more stringent environmental and food safety requirements. Pall faced the challenge of finding a more efficient and cost-effective solution for wineries to filter lees. The new technology must allow users to treat juice lees during the demanding harvest period and wine lees during standard cellar processing. The goal was to eliminate the use and disposal of filter aids while reducing oxygen pickup and improving the recovered product quality.
To overcome the drawbacks of RVD and chamber press filters, Pall developed the Oenoflow™ HS system. The new system utilizes microporous membranes similar to the hollow fiber membranes that have become the standard in wine clarification applications. The difference with the new Oenoflow HS membranes is that the hollow fibers have a larger internal diameter so that they can process higher solids, up to about 80% by volume. Since filtration is achieved with membranes and without filter aids, the operation is more hygienic and does not create DE waste for environmental landfills. One of the most significant benefits wineries realize by implementing the Oenoflow HS system is improved filtrate quality, which results in a higher value of the recovered wine or juice. The recovered wine or juice can be blended back into the original batch rather than being used in lower-tier products. Oenoflow HS operates as a closed system, allowing minimal oxygen pickup, typically around 0.2 ppm. This significantly improves compared to RVD filters, which often have an oxygen pickup of 4-5 ppm or higher. In addition, the microfiltration membranes provide improved and more consistent filtrate clarity compared to an RVD filter or chamber press.
A 12-module Oenoflow HS-A system, Pall’s new technology for lees filtration
Winery Implementation
A winery in Australia significantly improved filtrate quality by switching from an RVD filter to the Oenoflow HS system. The turbidity of the recovered white wine was reduced from 10 to 1 NTU while red wine turbidity was also much lower. In just 5 months, the winery recovered over 1,000 hectoliters of wine from lees, generating an additional $168,000 compared to the RVD filter. This increase in recovered wine value contributed to a quick return on investment, with a payback period of about 1 year.
Flexibility is a key advantage of the Oenoflow HS system, which can be utilized in three main applications. First, it recovers wine from fermentation and fining lees. Second, during the harvest, the system can process lees by incorporating the Oenoscreen rotary screen filter before the base hollow fiber system. Finally, when not processing lees, the Oenoflow HS can be employed for standard wine clarification, enhancing cellar filtration capacity.
The processing enhancements improved the performance of the XL clarification system and overall yield. The wine clarification flow rate increased by 15%, and chemical cleanings now occur weekly. Since installing the Oenoflow HS system, total recovery has improved, allowing tanks to be emptied more efficiently. White wine yield rose from 97.1% to 99.15%, while red wine recovery improved by about 2% to close to 97%.
In Chile, a winery uses the Oenoflow HS system to recover juice from must lees as a pre-concentration step for the RVD filter, producing high-quality, aromatic juice and reducing lower-quality yields. In Australia, a large winery employs the HS system to process wine lees during batch racking and to enhance standard wine clarification on weekends, increasing cellar filtration capacity by approximately 35%.
By implementing the Oenoflow HS system, wineries can recover higher-quality wine and juice from lees more efficiently and economically. When using the Oenoflow HS system to replace traditional filter aid-based technologies like RVD and chamber press filters, wineries can realize the following benefits:
- Higher quality, higher value recovered wine and juice and consequently a fast return on investment
- No filter aid consumption, handling or disposal complimenting winery sustainability programs
- Higher yields, improved wine and juice recovery
- Flexibility to process fermentation and fining lees, juice lees and post-fermentation wine for clarification
- The system offers flexibility in various ways, depending on the specific circumstances of the winery.
- Reduced labor requirements
With other value-added technologies like the Oenoflow XL, Oenofil or Pall Aria™ water treatment systems, Pall can help wineries produce the highest quality products at the lowest possible operating costs. When coupled with other value added technologies like the Oenoflow XL, Oenofil or Pall Aria™ water treatment systems, Pall can help wineries produce the highest quality products at the lowest possible operating costs.
Oenoflow HS wine lees samples
(left: filtrate, right: concentrate)
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