a disposable winemaking apparatus for fermenting wine containing skins , seeds , and stems that form a cap includes a single - use , dual chamber plastic bag that incorporates a mechanism to agitate and disperse the cap in order to maximize extraction of color and flavor . it also includes an integral press mechanism to squeeze out the fermented juice through a strainer , retaining the pomace in the disposable bag . the device may also be used for racking and transfer of wine during aging .