A Quick Guide to Unfiltered Wine
Each monthly Wine Club member tasting has a theme curated to the unique features of our partner winery to give members a deep dive into a new wine topic and expand their wine knowledge. This month’s theme is a hot topic of debate in the wine world: unfined and unfiltered wine!
Why is wine filtered?
Wines are naturally cloudy after going through the winemaking process because when grapes are pressed, their pulp, skins, and yeast remain in the liquid. Finished wine is not a naturally stable product, it’s always at risk of destabilizing and going bad (i.e., turning into vinegar), and any particles left behind in the wine following fermentation increases this risk.
When wine is unfiltered, the particles are left to naturally settle at the bottom of the tank and are then separated from the wine. However, this natural process can take months and small amounts of microbes are typically left behind in the wine.
That’s where filtration comes in: for time and cost efficiency and to ensure the wine is completely pure, the wine is moved through a two-part filtration system to quickly remove the particles from the wine and sterilize it before it is bottled.
To filter or not to filter?
Some argue that filtering wines strips them of flavor and complexity. It is believed that when left unfiltered, wines are more interesting and impressive with more character, texture, and body. These low intervention unfiltered wines are also thought to be a more clear and natural expression of the grapes and the land the grapes were cultivated in.
On the other hand, other experts argue that there is a minimal difference in the volume of particles left in unfiltered wine, so there is no detectable difference in flavor or texture. It is also cautioned that leaving wine unfiltered risks spoilage because yeast and other microbes remain in the wine in the long term, but advancements in winemaking technology has made this less of a risk in recent years. Two common approaches used to ensure the stability of an unfiltered wine are 1) putting the wine through a second fermentation called malolactic fermentation, which decreases the wines’ primary fruit flavors and freshness and gives the wine nutty, creamy flavors, and 2) adding a higher dosage of CO2, or sulfites, to the wine before it is bottled.
So, how does a winemaker decide whether to filter their wine or leave them unfiltered? Is minimal intervention most important to the winemaker, or is it more important that the wine is completely clear in the bottle? Are there time and space constraints in the winery that bar wine from being held in large takes for long periods of time while naturally particles settle? The list of considerations goes on, and it ultimately comes down to the winemaker’s preferred practices and the desired outcome of the wine. Be sure to ask about it next time you come across an unfiltered wine!
Learn more.
Want more wine knowledge like this, live and straight from the producer? In addition to three small-batch wines hand-picked and sent to your doorstep each month (or quarter), my Wine Club has an immersive live tasting experience with each small producer, so you’ll get hands-on knowledge directly from the people behind the wine in your glass. Learn more about the Wine Club here!
Cheers!