Wine Filtration

• In winemaking, there is insoluble matter suspended in the wine. This matter may include dead yeast cells (lees), bacteria,

• tartrates, proteins, pectins, various tannins and other phenolic compounds, as well as pieces of grape skin, pulp, stems and

• gums. Clarification and stabilization are the process that removing these matters before bottling. Filtration plays an

• important role in the process. All wines (with few exceptions) need filtration to get a brilliant appearance, to get the

• product free from any deposits and to make the wine stable, chemically and biologically.

• While fining clarifies wine by binding to suspended particles and precipitating out as larger particles, filtration works by

• passing the wine through a filter medium that captures particles larger than the medium's holes. Complete filtration may

• require a series of filtering through progressively finer filters. Many white wines require the removal of all potentially

• active yeast and/or lactic acid bacteria if they are to remain reliably stable in bottle, and this is usually now achieved by

• fine filtration.

Most filtration in a winery can be classified as either the coarser depth filtration or the finer surface filtration. In depth

filtration, often done after fermentation, the wine is pushed through a thick layer of pads made from cellulose fibers,

diatomaceous earth, or perlite. In surface filtration, the wine passes through a thin membrane. The finest surface filtration,

microfiltration, can sterilize the wine by trapping all yeast and, optionally, bacteria, and so is often done immediately prior

to bottling.