Read here to learn about disgorging (disgorgement) of Champagne
Photo source: wineterroirs.com
After the bottles has produced the last few percentages of alcohol and created the bubbles (Carbonation) from the fermentation. They will create a byproduct which is the yeast. As the yeast is forming in the bottles they will be rotated in a special way called "riddling" (Click to learn more about it). After the bottles have been put in the right position, all the yeast will be at the top of the bottle that is now turning downwards. To get all the yeast out, the top of the bottle will be frozen. After the yeast is frosen the bottle will be held by hand like on the picture here. The disgorgement is a quick movement which is many tasks in one motion. First of all you have to turn the bottle quickly while removing the cap from the bottle with a "Disgorging Key" which is the tool that is seen in the right hand on this picture. When you do this motion the perfect way, all the yeast wil shoot out and you will be left with the pure product. After disgorging the bottles will typically receive a "Dosage" (Click here to learn more) before being put back in the cellars to age more.
Cheers // Best regards - Champagne Season