The eminent late and lamented professor of Enology Emile Peynaud said, “Clarity achieved spontaneously is never sufficient “.
Regardless, winemakers and wine enthusiasts constantly debate whether filtering causes loss of appreciable amounts of flavour. Karl Kaiser, co-founder and long-time winemaker of Inniskillin Wines in Niagara-on-the-Lake (now Vincor) contends that heavy filtering robs the wine of a lot of flavour. Yet light filtering does no harm to most regularly available mainstream wines. As a winemaker all you need to do is examine the residue on a filter pas after filtering. You can then make a decision.
Michel Chapoutier, the owner of a reputable Rhone negociant company and winery, claims filtering diminishes the pleasure of wine, and needless to say DRC (Domaine de la Romanee Conti), Domaine Leflaive, Leroy, Jadot, and Faiveley never filter their wines or at least claim not to filter any of their wines.
In California, Robert Mondavi, Napa Cellars, Au Bon Climat, and many other quality-minded wineries have their filter pads put away in boxes, inaccessible to all.
Filtering has become fashionable in the last 40 years since young customers expressed dismay upon noticing particles in their wines. A natural wine throws sediment, as do all vintage ports. While vintage port enthusiasts know that such wines must be decanted, young consumers of still wine like brilliantly clear wines, which winemakers achieve easily by heavily filtering red wines, and cold stabilizing white wines. In both cases the wine suffers and loses at least some flavour. Most connoisseurs agree that it is better to put up with a few floating particles than have a brilliant wine with decidedly less taste. K. Lynch, a famous California importer ands author of wine books, states that filtering not only robs the wine’s taste, but also shortens its shelf life. He has recorded cases supporting his claim.
Filtering essentially is ruining the taste of the wine both winemakers and growers try to create. After all that labour and care, within a few minutes the wine is denuded of most of its delicate flavours.
In the past, wine was aged not to so much to impart an oak flavour, but to clarify it by using gravity and time. During its long sleep in barriques, the phenolic compounds in contact with oxygen clump into molecules large enough to drop out of the wine, which, meanwhile continues to gain complexity, richness ands silkiness much valued by consumers.
Most of the dead yeast cells also fall out. Some bacteria remain, but without residual sugar they have nothing to feed on and the natural acidity of the wine acts as an inhibitor.
Even the most caring winemakers, in huge wineries churning out millions of cases of “ commercial” wine filter, some heavier than others. Most overseas wineries exporting to distant countries prefer to filter to avoid complaints and clarity problems, but most also agree that filtering diminishes the taste of the wine. Sterile filtering as most German wineries practice it, the winemaker buys “ insurance “; in that the shipment arrives at its destination without any noticeable defects. But when it comes to taste the wine lacks its orignal flavour.
If you ever visit a small winery and strike up a conversation with the winemaker and/or owner, ask to taste an aging wine from the barrel. If possible compare it to a filtered version and you will be simply amazed at the difference
Wine filter facts
The first filters were hemp sacks, used both to clarify wine and to strain out dead yeast cells
Pasteurisation, developed in the 1860’s was the main technique used to remove microorganisms before the Seitz Werke in Germany developed sterile filtering
First Seitz filters were crude in that asbestos and cellulose were poured into the wine and then filtered out.
Filter pads to remove bacteria are 10 times finer than pads that just make the wine visually clear.
Sterile filtration renders wines crisp in hot climes, by stopping malo-lactic fermentation.