Does Filtering Wine Remove Sulfites?

The filtering process that wine undergoes before bottling does not remove sulfites. It only extracts particles that might be offputting for drinkers. But it does not impact the sulfite content of the wine at all.

It’s worth noting that wine naturally contains only small amounts of sulfite. However, many vintners add sulfites artificially to increase the wine’s shelf-life. If you prefer low-sulfite wines, go for natural, low-intervention, organic, or biodynamic wines.

You might come across devices or substances meant to remove sulfites from wine before drinking it. Among them are purifiers that you can attach to the bottleneck, filter membranes, wands to swirl in your glass, and sprays. Whether these items actually reduce sulfite contents is arguable.

How Is Wine Filtered?

Technically speaking, there are two general approaches to removing sediments from wine: filtering and fining. Vintners often use both of them to optimize their wines.

During the filtration process, the wine is moved through a material similar to a coffee filter. It has tiny pores so that liquids can move through. But particles are held back and filtered out. Filter membranes are available in various sizes. Some filter only bigger particles, but others even remove microbes from the wine. It is not uncommon that wine goes through multiple filtering instances with membranes of different sizes.

Wine fining aims to remove even the smallest particles and optimize the flavor at the same time. Winemakers can extract crystallized acids or tannins by adding substances like gelatine, casein, or isinglass to the wine. These materials bind themselves physically to the particles, form bigger clusters, and sink to the bottom of the vessel. The winemaker then racks the wine to separate these clusters from it.