riddling

The process in champagne production whereby the yeast sediments which are deposited in the bottles are collected toward the neck to facilitate removal. The bottles are gradually tilted downward, over a period of weeks, while receiving a daily twist to help free the sediment which moves ever closer to the top of the neck. Once all the yeast residue is collected there, the neck of each bottle is quickly frozen and the closure emptied. Gas pressure inside the bottle expels the small bit of ice in which the sediment is entrapped, leaving a wine that is clear.