HOW DO I PROTECT MY WINE'S SHELF LIFE AND FLAVOR?
Winemakers are practical microbiologists. They use the alcohol levels, oxygen content, and pH in wine to promote the growth of bacteria and yeast that create a great wine – and inhibit the growth of organisms that can ruin the wine. This delicate balancing act takes place from the grape harvest through the fermentation and barrel aging of the wine. But then it is time to remove those bacteria and yeast and stabilize the wine for bottling.
The organisms of concern to the winemaker are some lactic acid bacteria (LAB), especially Oenococcus oeni, that provide desirable flavor and aroma characteristics to the wine during fermentation and aging, but can
produce undesirable aroma and flavor compounds later. Acetic acid bacteria (AAB) such as Acetobacter and Gluconobacter can also cause spoilage issues.
Wine may also be spoiled by yeasts. The most common spoilage yeasts are Saccharomyces cerevisiae and Candida species, though other yeasts such as Debaryomyces or Kloeckera or Zygosaccharomyces can also find their way into the wine and act as spoilage organisms.
The schematic below shows a simplified wine clarification, stabilization and packaging process. The fermentation and aging processes are complete in this example, and the wine has been bulk filtered before being stored in a holding and stabilization tank.
The housings marked 1 and 2 are clarifying filters. As described in an Application Summary,
“Choosing the Right Filters for Wine Clarification”, these filters may be initial stabilization filters, depending on the type and number of microorganisms present in the wine at this stage.
The final microbial stabilization is accomplished by passing the wine through the bioburden reduction filter (housing 4) and then the sterilizing filter (housing 5).
The most commonly used filter for removing organisms from wine is membrane based with either 0.65 or 0.45 micron pore size rating. These will remove both bacteria and yeasts. Winemakers may choose the smaller pore size to assure capture of all bacteria, including the vegetative forms of some species that may survive in wine, but there is a risk that some flavor or color elements will also be captured by membranes with 0.45 micron membrane filters. Contact Us to learn more about what filter pore size might be right for your wine.
Learn more by reading our Application Summary - "Protecting the Quality of Wine – Filters That Remove Spoilage Organisms".