Why decanting ?

When decanting you pour the wine from a bottle to a carafe in order to segregate the sediments from the wine itself

Preparation

A wine bottle is always stored laying down. This is to assure that the cork don’t dry out.
When we take out a bottle from our cave, in is necessary to do so very carefully. 24 hours before drinking the wine we take it out and stand it up right. This is to let the segments settle at the bottom.

Decanting
Looking through the bottles neck with a lit candle behind it, it is easier to see the segments as they approach the neck. One have to keep in mind that any sudden movement can ruin the process.