filtering

A step used by some winemakers to clarify wine just prior to bottling. The purpose of filtering is to remove yeast cells and other microorganisms that could spoil the wine, as well as any remaining sediment that would keep it from being crystal clear (which is what most of the public expects). The wine is pumped through one or more various filters including those made of cellulose, pads coated with diatomaceous earth, or especially fine membranes. Today's modern winery has filters so fine that they can remove infinitesimal particles. When such fine filters are used, the process is called sterile filtering. Some winemakers argue that this precise filtering extracts flavor and character that the sediment lends the wine. See also fining; racking; unfiltered.