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How do I kasher a dishwasher?
by Rabbi Dovid Bendory, 23 Sivan 5765 (June 30, 2005)
OK, so you need to kasher a dishwasher. How do you do it?
For those who hold that a dishwasher can be kashered, I recommend the
following kashering procedure. This kashers the dishwasher by
internal hagala — similar to boiling water in
Remove the racks. Inspect the racks, the inside of the dishwasher, and
especially around the drain filter for any pieces of food. Be especially
careful to remove the filter, clean in and around it, and to check inside
under it to be sure there is no food. Return the racks to the dishwasher.
You must do this even if you are 100% sure there is no food in the
- Let the dishwasher sit unused for 24 hours.
Run the empty dishwasher through a full cycle with soap on the highest
Put two large stones in the oven on the highest temperature for at least one
hour. (I use bricks.) The temperature should be at least 500
oF, but use a higher setting if you have one. (This will likely smell
a bit as the moisture is cooked out of the rocks. Sorry.)
Once the rocks are heated in the oven, put one on each rack of the
dishwasher. Be VERY careful. If you drop one of these rocks,
depending on your floor, you will have permanent damage. The rocks are hot
enough to melt the plastic racks on contact and will cause serious
burns if you touch them by accident. The way I handle the rocks is as
Prior to putting the rocks into the oven, I put pieces of wood onto the
plastic racks in the dishwasher and practice placing the cold rocks onto
them. In addition, I make sure the rack will slide in and out easily
with the rocks in place.
I put the rocks into the oven on small aluminum tins. When the rocks are
fully heated, I carry them to the dishwasher by lifting the tins. I
practice carrying them over to the dishwasher on the tins and putting
them onto the wood.
Finally, I punch lots of holes in the tins so that water fill flow through.
Close the dishwasher and run it through a full cycle on the highest
temperature setting with soap. Because of the hot rocks, the water inside
will boil. Don't be surprised if you get steam seeping out of the
At the end of the cycle, open the dishwasher, pull the racks out and let
everything sit and cool for an hour or so. Don't touch the rocks —
they will still be hot.
After the rocks have cooled and you can safely remove them, you're finished.
You now have a kosher dishwasher.
Before following this procedure it is essential that you check with your
communal rav with regard to the dishwasher, as some hold that a dishwasher
cannot be kashered at all.
References: See Hagalas Keilim 13:225-228.
Questions to ponder:
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