After pressing, the must from white grapes contains significant grape solids and is very turbid. To improve ferment quality, the juice is often clarified.

The objectives of this clarification are to remove any solid particles suspended in the must and thus produce wines with cleaner flavours with more finesse and less bitterness.
The level of clarification required depends on:

  • The health state of the vintage
  • The processing method: violent processing and the juice from the final pressings requires more clarification
  • The wine style required: some winemakers clarify very little in order to produce more full-bodied, complex wines.

This clarification is normally achieved by:

  • Cold settling overnight or longer (ideally below 15ºC), possibly with pectolytic enzymes added, followed by racking.
  • Centrifugation
  • Diatomaceous earth filtering

After clarification the winemaker is left with a clear or slightly hazy juice, and a small proportion of juice that is thick with solids, known as lees.

If cold settling is used, the lees generated are often passed through a rotary drum vacuum filter in order to recover more juice.