Definition: Earth filtration

This is often the last step before bottling.

The wine is filtered "on earth" in order, above all, to remove any suspended impurities. The "earth" in question is actually a fossil conglomerate of single-celled algae with thin shells, major components of plankton (diatoms: 60 to 100 million years old), ground as fine as flour. This filtration also gives the wine its final brilliance.

After a long ageing process, natural sedimentation sometimes allows the wine to be bottled without any filtration.