Most of the red wine that we see on store shelves or on a restaurant's wine list has been filtered, which means that the small particles that are involved in the wine-making process have been removed. Unfiltered wines leave these particles in tact, allowing them to settle at the bottom of the bottle. Though this may sound like an unappealing idea, many winemakers believe that these particles are necessary to keep the authenticity of the wine's aroma and flavor in tact. Note that although many winemakers believe in the craft of unfiltered wines, many do not.
According to GrapeCrafter, which is a wine technology blog, the idea of unfiltered red wine was first created by the Martin Ray Winery, which is located in Santa Rosa in the heart of the Russian River Valley wine country. It was later made famous by Robert Mondavi, the famous California winemaker who has produced unfiltered pinot noirs and cabernet sauvignons.
Filtered Vs. Unfiltered
Filtering wine removes sediment, which are the grape particles that tend to settle at the bottom of the wine bottles. Though these particles supposedly do not affect the wine's taste, they can affect the level of consumer satisfaction, particularly at restaurants. Customers who see sediment at the bottom of wine glasses or bottles are more likely to send it back, according to FoodandWine.net, and restaurants must decant wine that has not been filtered, something that is not always needed for filtered wines.
The easiest way to tell whether a wine has been filtered is to observe its level of clarity. An unfiltered red wine may appear murky, "polluted" or dark. This is not a bad thing, it simply means that the wine was probably not filtered. Like coffee, wine is put through a filtration process that removes small particles. Many winemakers argue, however, that this process is not only unnecessary but actually bad for the wine as filtration can affect the wine's flavor and aroma.
Many vintage and high-quality wines are not filtered because the winemakers believe that the act of filtration will cause their wine to lose flavor and aroma, thereby reducing its overall quality, popularity and, ultimately, price tag. Unfiltered wines are generally accepted within the wine connoisseur community because it understands that unfiltered wines characteristically have sediment at the bottom of their bottles. To avoid drinking the sediment, which does not taste particularly good, many imbibers decant and pour the wine very carefully to keep the sediment out of wine glasses.
Though most wine drinkers enjoy filtered wines, unfiltered wines are particularly popular in California's wine country. In addition to Robert Mondavi and Martin Ray, Dehlinger, Paul Hobbs, Newton and Williams-Selyem all produce unfiltered wines. Sonoma and the Russian River Valley wineries are particularly fond of unfiltered wines.