What does Filtration mean?

Filtration means the wine passed through a filter before bottling, removing yeast, bacteria and particles to make it clear and stable.

Also known as: Filtered wine

Filtration means the wine is pumped through a filter before bottling to remove particles, yeast cells and bacteria. The aim is partly to make the wine clear and partly to make it microbiologically stable, so it does not start fermenting again or change in the bottle.

There are different types of filtration. Coarse filtration with filter sheets or diatomaceous earth, for example, removes larger particles and haze. Membrane filtration with very small pores can remove virtually all yeast and bacteria, known as sterile filtration. It is especially common for wines with residual sugar or that have not gone through malolactic conversion, where the risk of renewed fermentation in the bottle is otherwise higher.

Filtration is different from fining, in which an agent such as bentonite or egg white is added to bind particles that then sink to the bottom. Many wines are both fined and filtered.

How much filtration affects flavour is debated. Some producers believe heavy filtration can strip aroma and body and so choose to filter gently or not at all. Others see it as a sensible safeguard. On the wine page the information shows how the wine was treated before bottling.