Steamer (Passover) Status: Can I use a steamer to kasher my counters? Can I use a steamer to kasher my counters? -- The general rule (as per Iggeros Moshe YD 1:60) is that one must kasher with water which is in liquid form, and cannot kasher with steam. Accordingly, a steamer can only be used for kashering if two conditions are met: firstly, the steam must condense to the point that the whole area being kashered is covered with water, and secondly, that water must be at approximately the boiling point (212 F). Most steamers sold for cleaning purposes do not meet these criteria and cannot be used for kashering.