For packaged wine to be successfully placed on the market within the country of import, it must be microbiologically stable, visually clear and particulate free.
The accepted method of achieving microbial stability is to filter the wine using membrane filtration immediately before the wine moves into the packaging machine. The membrane filters should be validated to remove wine spoilage organisms without affecting the wine's essential characteristics, where typically 0.65 micron membranes are used for red wines, and 0.45 micron membranes are used for white wines.
Prefilters are used to retain fine particulate (and in some cases, microbial retention is also necessary), before the wine reaches a final membrane filter - which must offer validated microbial retention, be integrity testable, easy to clean and high flowing. Final filters should demonstrate retention to Sacchromyses, Brettanomyces, Acetobacter and Oenococcus.
The standardization / pre-stabilization process addresses the wine's microbial stabilization, clarity and potential for blocking subsequent final filters prior to packaging.
When preparing the wine for export, the winery will adopt a method of standardization, to achieve stability during transport, protect essential characteristics and reduce the levels of sulfur dioxide required.
However, these standardization treatment methods vary between country, region, winery and wine type, leading to variable qualities of wine being received by the packaging facility. In response to this, the packaging facility should make a quick assessment of the incoming wine to understand its filter blocking potential (Filterability Index or FI testing) and then perform its own standardization process when off-loading the wine from the road tanker, prior to storage.
Historically, standardization was carried out by powder filtration or using sheet filters, but other technologies have become available which have offered significant improvements, including lenticular / stacked disc solutions, cross flow filtration and cartridge filtration. The table below shows a comparison of the different standardization technologies to achieve the target conditions in the wine.
The use of cartridge filtration is an attractive option for wine standardization for tanker off-loading, as there are numerous advantages over the other technologies.
The filter cartridges used are typically available in a range of absolute retention ratings and should have been validated by the filter manufacturer to give specific retention against spoilage organisms under different operating flow rates or feed pressures. This in turn leads to very well-defined retention characteristics.
As a result, the final filtration can be easily tailored to suit the type of wine being filtered, allowing flexibility to optimize the process against specific requirements.
Operational costs are minimal and are dictated by the frequency of filter change-outs due to blockages, which will be influenced by the level of contamination within the wine.
However, cartridge filters can be easily cleaned to aid regeneration and repeated use, so extended operational lifetimes can be easily achieved. Effective cleaning is a significant drawback experienced with the operation using the sheet / lenticular format of filter. Due to the construction of sheets / lenticulars, the filter media is very difficult to regenerate through cleaning and often leads to damage rather than effective regeneration.
By standardizing the quality of wine delivery, the wine bottling / packaging facility can access further cost savings in the form of extended operational lifetime of the final filters used prior to bottling.
Capital costs are dictated by the complexity of the system including the degree of automation required. For a simple manually operated filtration skid, capital costs are kept low and are attractive to bottling / packaging facilities with multiple loading / off-loading locations within the facility. Full automation can be included or added to the system later to help optimize further and improve filter lifetime through standardized CIP (clean in place) regimes.
For wine tanker loading / off-loading, Parker's PREPOR NG range of cartridge filters is a highly effective solution. They utilize a graded density polypropylene filter media which has been developed with the global wine industry to achieve optimum operation in wine standardization applications.
The filter media used in PREPOR NG filters retain spoilage micro-organisms and fine haze forming colloidal material while being capable of regeneration through chemical cleaning and backwashing operations. As a result, PREPOR NG filters can reduce the FI value of wines to deliver the correct quality of filtered wine for tanker loading / off-loading while being capable of repeated use under variable loading conditions.
There are many approaches to the wine standardization process, however, the requirements of the process are consistent: to protect the essential characteristics of the wine during storage and to standardize it prior to final filtration.
Cartridge filtration with PREPOR NG filters is an economical and flexible approach to the processes of wine standardization for tanker loading / off-loading and delivers on the key criteria required to perform optimally in this application.
Use of PREPOR NG cartridge filters for tanker off-loading applications will return significant processing cost savings for wine bottlers / packagers in the forms of:
This post was contributed by Lee Pattison, food and beverage product manager, Parker Bioscience Filtration, United Kingdom.
Parker Bioscience Filtration offers filtration solutions to protect the quality and taste of beverage products. By working with our application experts, manufacturers can develop a tailored solution to ensure their beverage is free from contamination, full of flavour and visibly clear.