FILTRATION FOR WINERIES: Purifying Wines With Traditional Means and Cutting-edge Technology  

By: Cheryl Gray

“Why?” is not the question when it comes to filtering wine. How best to perform filtration is the real question, answered in part by the technology and innovation now available.

  First, some history on the evolving process of filtration may help wineries looking to upgrade gain some perspective on how far the filtration industry has come.

  For more than a century, small wineries have used sheet filters. For the small operations that need more flexibility to create a variety of small wine batches, sheet filtration is modified to include plate and frame format. Lenticular modules represent a modern-day approach to sheet filters. The modules are assembled in an enclosed area to avoid drip loss and to provide extra flexibility, better hygienic conditions and, of course, ease of use.

  DE filtration (Diatomaceous Earth) was at one time the most common filtration method used to clarify wine on a large scale. DE filtration systems use rotary drum filters and chamber press filters that can remove a high volume of solids. However, their open design lets in oxygen, which can ruin wine quality. The result is recovered wine that requires more processing and is ultimately downgraded to be used in blends instead of added back to the original wine batch.

  Crossflow membrane systems have replaced DE filtration in many of the world’s winemaking regions. Wine filtration systems based on the crossflow membrane method trigger cost savings by reducing wine loss, labor and other factors normally associated with filter-assisted technologies. Additionally, by replacing DE filtration with crossflow membrane filtration, wineries can operate without creating the landfills formerly used to store solid waste, thus removing many of the inherent problems landfills pose that threaten the environment and operator safety.

  Finally, there is the centrifugation method, which is typically used at larger wineries. Centrifugation is usually followed up with a crossflow filtration system to achieve the clarity each winery wants to accomplish with its finished product.

  From flat sheet filtration used to the more sophisticated centrifugation and crossflow membrane systems, nearly all wineries filtering their wine do so with a checklist of items they want to separate from their products. Beginning with post-fermentation, removing things such as dead yeast cells, bacteria, grape skins and seeds is important. During the aging process, hazes and deposits form from combinations of proteins, phenolics, tannins and polysaccharides. In low temperatures, unstable bitartrate can form the glass-like crystals seen in, for example, white wine.

Among the companies specializing in helping wineries increase wine yields and prevent waste is Pall Corporation. This global supplier of filtration, separation and purification products is headquartered in Port Washington, New York, with manufacturing plants and offices located elsewhere in the United States and around the globe, including a plant currently under construction in Singapore.

  The company’s founder, Dr. David Pall, started the business in 1946 as Micro Metallic Corporation. Initially concentrating on creating filters for aircraft, the company changed its name to Pall Corporation in 1957. What would follow would be more than 50 years of innovation. In its early days, Pall Corporation became the frontrunner in providing filtration systems designed to protect the safety of global blood supplies and improve the outcomes of patients receiving blood transfusions.

  Dr. Pall received nearly 200 patents over his lifetime and was awarded the National Medal of Technology by President George H.W. Bush in 1990. The award recognized Dr. Pall’s vast achievements in advancing filtration technology, including the groundbreaking roles the company played in historical events, such as man’s first walk on the moon, the Three Mile Island clean-up, Desert Storm and the construction of the $10 billion Eurotunnel beneath the English Channel between France and England. 

  One of the company’s primary services to wineries is providing filtration systems that maximize yields from wine lees. According to experts, this sediment at the bottom of wine tanks can yield up to 15 percent of total production for a winery. Pall focuses on multiple kinds of lees because missing any one of them presents a costly loss for wineries if not recouped through filtration. Pall says it recognizes the filtration challenge that wineries face in recovering products while at the same time meeting environmental demands to reduce waste. Pall notes that its products are designed to accomplish both. 

  Pall designs filtration systems to fit the needs of wineries of all sizes. For smaller operations, there are the company’s sheet filtration systems. There are products such as Pall’s Oenoflow PRO XL systems for medium and larger wineries. Pall says that these products clarify wine in one process, absent any filtering aids, centrifugation or adverse impact on the wine. The system is fully automated is designed to provide wineries with a cost-saving alternative to traditional wine filtration methods by boosting yields, reducing waste and maintaining even filtration quality. 

  The Oenoflow Pro System has a feature called an Optimized algorithm developed by Pall, which is connected to Pall servers through a secure line. If the connection is ever interrupted, the system continues to operate. The Optimized algorithm adjusts all of the system’s filtration settings, and the user-friendly system only requires some basic information to start the filtration process. For greater flexibility, the algorithm can be disabled or enabled at any time.

  Other companies tout their own innovations in wine filtration systems. One of them is The Vintner Vault. Founded in 2003, the company has two California locations, Paso Robles and Temecula, with a third location in Hye, Texas.

  The Vintner Vault custom-builds winery equipment of every sort and has installed filtration systems of all types for wineries of every size. It offers consulting and turn-key services for clients looking to start new or upgrade existing operations. The company offers filtration options that include frame and plate, centrifuge, crossflow and even a filtration system that uses reverse osmosis. Andrew Berg, vice-president of The Vintner Vault, says that primarily, medium- to large-size wineries use the reverse osmosis system. 

  Unlike a traditional filter, the wine product that passes through the membrane used in reverse osmosis does not contain any of the wine’s flavor or color components. This means virtually no loss of anthocyanin, phenolics, tartaric, malic or citric acids essential to good wine. 

  A reverse osmosis membrane can perform this unique task because it is 10,000 tighter than a regular filter. Wineries use this type of system to adjust alcohol content and flavor concentration, remove water from juices, remove sulfide, purify water, restart fermentations that get stuck and reduce volatile acidity. With regard to the latter, experts warn that the reverse osmosis system works in tandem with a volatile acidity system in order to effectively remove VA. 

  Many small, start-up wineries and home winemakers turn to Northern Brewer of St. Paul, Minnesota for wine filtration supplies. The company began as a small storefront in 1993 and has grown into a competitive winemaking and home brewing supplier. Its wine filtering systems handle anywhere from fewer than six gallons up to 60 gallons of wine per hour.

  Winemakers use multiple techniques to improve wine yields and the appearance of their wines, along with shelf life. Executing these tasks correctly can increase profits and cut waste while creating a clear and stable wine product.

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