What does "filter" mean and why is it done? Does it imply low-quality wines or wines stripped of flavor? Does it guarantee the quality and drinkability of the wine so labeled? The American Heritage Dictionary defines "filter" as "a porous material through which a liquid or gas is passed in order to separate the fluid from suspended particulate matter" This is a fairly wide definition which can mean separating everything from the stems of the vineplant to the bacteria which remain in the finished wine.

         Most winemakers filter their wines to one degree or another and for several reasons including safety, consumer acceptability and the constraints of time. In terms of safety, since wine is an agricultural product it is susceptible to attack by large and small organisms. Insects are drawn to its aromatic grapes from the beginning, and many is the bug that has gone out of existence--perhaps without much pain--via the alcoholic fermentation. Unless the winemaker is not worried about, as one friend says, “wines with some body”, he or she will therefore have to sieve these little critters out. It is rare, but consumers in areas with less than modern winemaking techniques can still find wings in their wines. More commonly found are tinier organisms--bacteria and fungi--which can ruin the entire vintage unless they are prevented from extended contact with the grape-juice or wine. Wines can become acetic--get too vinegary--or become oxidized--making them more reminiscent of Sherry than Chardonnay--because of the action of uncontrolled microorganisms. To a large degree, filtering can prevent these and other problems.

         Some wines are perfectly safe to drink yet are unacceptable to most consumers. Examples include wines which throw natural deposits in various forms, from tartrate crystals (they look like tiny pieces of glass) to the silty lines of fine sediment often found in older red wines. They are absolutely harmless deposits; but their appearance in a bottle causes most consumers to bring the stuff back to the store for a refund---or a different brand. Both “problems” can be solved to render the wine perfectly clear. In the case of tartrates, winemakers can “cold stabilize” the wines and then filter when finished, preventing the tartrates from ever entering the bottle. And knowledgeable consumers can deal with the sediment from old wine simply by carefully decanting the bottle off the sediment.

         Finally, filtering makes the quick release of a wine possible. Instead of waiting for gravity to take its inexorable, but very time-consuming effect on deposits, winemakers can speed up this clarification process by filtering. They have at their command filters which can siphon elements in the wine down to the sub-micron level (a micron is one millionth of a meter) which will block most yeasts and bacteria, so-called “sterile filtration”; in the process, many contend, you also strip color and flavor.

         Can speed up the clarification; but should they? “Any time you clarify a wine, you take something out of it, usually aromatics and mouthfeel, the tactile aspect” says John Kongsgaard, winemaker at Newton Winery in St. Helena. Kongsgaard doesn’t usually filter his wines, red or white. “It starts in the vineyard, where we farm for well-balanced fruit to start with; once (the wines) are through their alcoholic fermentation and they’ve finished the malolactic (basically, a secondary, textural- and flavor-modifying transformation of the wine) and you let them sit at least a year and a half in the barrel, there is no need to filter them.” (neither Newton’s 1992 “Claret” ($11)  or his 1992 Merlot or Cabernet ($23) are filtered; however, only the Cabernet and the Merlot are so-labeled). Basically, this minimalist winemaking is analagous to old-fashioned child-rearing: watch the little rascals, make sure they don’t get sick or fix them if they do and let them develop their personalities over time without a lot of fuss. If all goes well, when they get out in the world, they’ll be fine. This does, however, presume that you have time to tend your wines--and your kids--for proper results

         Of course, human behavior has changed along the way. Now we have clean, in-door toilets, deodorants, acne-removers, store-bought butter and speed-reading courses. And so it is with wines. Where once wine drinkers accepted sediment, peculiar smells and chewy-tasting wines as normal, today’s consumer is more likely to sue than to accept. So, winemakers take the cue and do whatever they have to satisfy an ever-more finicky market.

         Many, like wine writer Parker, and wine importers like Kermit Lynch and Peter Weygandt (whose wines are identified by their names on the label), feel that filtration is taken to extremes in today’s wineries. They use terms like “evisceration” and “emasculation” when describing the effects of ham-handed filtration. Whether or not it is in reaction to this thinking, many winemakers are eschewing filtration, if not for all their wines then at least for their special selections. “If I have so much character in my wine, why should I want to take anything out that I don’t have to”, says Robert Sinskey of the eponymous winery out of Napa county. Sinskey’s 1990 “Carneros Claret” ($22-$25) label does not say so, but the wine in the bottle is unfiltered (“I don’t believe in the term as a marketing ploy”): the wine itself is an extremely fine dry Bordeaux-style red wine; but the bottle has a literal glaze of sediment coating the glass. Sinskey and other, mainly small, winemakers have accepted the risk of minimal or no filtration, whether stated on the label or not, in return for being able to offer wines they feel would be diminished otherwise.

         I say mainly because the world's largest winery--E & J Gallo--evidently has been going in that direction for a while, at least with its "Sonoma Estate Wines" line made at their winery just north of Healdsburg in Sonoma county. Carmen Castorina, National Sales Director, told me that "our 1991 Estate Cabernet ($40, which just won a Gold Medal at the Dallas Morning Times Wine Competition) and our Zinfandel ($14) receive only minimal filtration."

Copyright © Patrick W Fegan