Would the Al have to be aqueous? Nope, drop in some aluminum foil. It's definitely not pure aluminum, but it is enough to cause a good reaction. the Al can be in any state (though... solid is perferable) Al foil works very well ifyou crumble/rip it right... LOTS of surface area as for reaction... fermentation just be carefull. one time i didnt put enough Al foil in and it didnt blow, so i undid the lid and got acid vapour down my throat, not nice