From: Rabbi Moshe Sofer
To: Rabbi Pinchas
A teacher rules that plum brandy distilled in a pot used year-round for malt whiskey could be drunk during Pesach. The Chasam Sofer rules this was an error, since the sharp pungency enhances rather than diminishes the absorbed chametz flavor.
Source: Shu"t Chasam Sofer OC §108