From: Rabbi Moshe Sofer
To: Rabbi Tzvi Hersh
Barrels of fruit brandy containing grain spirits (a chametz mixture) are included in a pre-Pesach sale to a non-Jew, but the agent's sale document may not have explicitly mentioned chametz. The Chasam Sofer rules the sale was likely valid since 'chametz' inherently includes mixtures.
Source: Shu"t Chasam Sofer OC §109