Apparatuses and methods are described for demolding articles from molding trays, including confectionery articles such as molded chocolate pieces, utilizing the resonant frequency of the mold tray. The methods may also be used to improve the distribution of edible liquid starting material deposited in mold tray cavities utilizing the resonant frequency of the mold tray. The invention is also directed to a process for controlling molding and demolding processes, such as by determining an empty state of a demolded mold tray according to its characteristic resonant frequency.