Once the lees has finally reached the bottom, it's time to disgorge the wine. The neck of the bottle is frozen, thereby freezing the lees. When the bottle cap is popped off, the pressure of the carbon dioxide pops off the frozen lees. What's left is a small space inside the bottle where the lees used to be. Before the bottles are corked, a little dosage — a mixture of the base wine and pure cane sugar — is added. The sweetness rounds out the flavors and balances any acidity.