Rabbi Shlomo Cohen
There are several possibilities that are apparent in permitting or prohibiting the use of a
household dishwasher for both meat and dairy utensils. One possibility is that one may use
the dishwasher,one load after another, without waiting at all between loads, as long as any
real foodstuffs have been cleared from the unit. A second possibility would require
separate racks for Milchig and Fleishig. A third possibility is that the nature of the
dishwasher precludes using the same machine for both types of utensils. Let us examine
the total picture.
Igros Moshe (Orech Chaim Chelek 3 Simen 58) dealt with
the question in 5726 (1956) regarding kashering a dishwasher from Chometz to Pesach use.
At that time, household dishwashers were not being produced. Rav Moshe’s T’shuva was
concerned with kashering metal or porcelain commercial dishwashers from Chometz to
Pesach use. Anyone familiar with older commercial dishwashers will know that they were
vastly different from those in our kitchen today. For one thing, they were open at both
ends, they used much hotter water and the water was under much greater pressure.
To kasher it from Chometz to Pesach Rav Moshe clearly requires Hagola, thoroughly
drenching the entire inside with boiling water after waiting 24 hours. He adds that a hot
rock should be utilized to be sure the water does not cool down. Rav Moshe then speaks
about this same dishwasher being kashered between meat and dairy. The Halachos for
kashering for Pesach are similar to those for meat and dairy, however, he indicates that,
because of absorbtions, new racks for the dishes should be used. He also tells us that the
water temperature in those dishwashers was 180oF.
Rav Moshe gives us two additional T’shuvo)( (Yorah Deah Chelek
2 Simen 28 & 29) regarding dishwashers . One is dated 5724 and the other 5732. Both
refer to home use but are speaking of the old porcelain covered metal models. In short,
Rav Moshe permitted their use from Milchig to Fleishig and back, one after the other, with
the proviso that there be separate racks for Milchig and Fleishig. He prohibits kashering
these dishwashers from Chometz to Pesach or from non-kosher to Kosher. In permitting the
use between meat and milk he relies on a series of leniencies.
Interestingly, neither of these two T’shuvos make any mention of Yad Soledes Bo as a
Can these T’shuvos be extended to include today’s plastic lined dishwashers and racks?
We will need to determine if there are any Halachic differences between the dishwasher
and the kitchen sink or the plastic bucket many use to wash dishes in. May those be used
for meat and dairy utensils one, after the other, without waiting between? Generally
women are very strict about not doing so.
The issues which need to be explored include:
a- Is plastic kasherable
b- Nosen Ta’am Lifgam
c- Ben Yumo, waiting 24 hours between uses
d- Nosen Ta’am Bar Nosen Ta’am
e- Bitul B’Shishim
f- Yad Soledes Bo
g- K’bol’o Kach Polto
h- Minhag Yisroel Torah Hee
i- Al Titosh Mi’Toras Eemecha
a- Most Poskim)( (See Sefer Hagalas Keilim Perek 12
Sif 301″Nylon”) maintain that plastic is kasherable.We would use whatever method that
Traifed the plastic to Kasher it. Usually this amounts to boiling water although other
methods may suffice in different situations. Getting boiling water onto all the inside
surfaces of our dishwashers is problematical, to say the least not to mention the
impossibility of getting a hot rock onto all the surfaces and not ruining the plastic in doing
so. Therefor, we must ascertain whether Kashering is needed at all.
The Shulchan Aruch ( (Yorah Deah Simen 95 Sif 3 in the Ramah)
deals directly with the issue of washing dishes together. The Baday HaShulchan explains the
issues clearly, although one must learn the Baday and the Biurim to fully appreciate all the
specifics. The Mechaber, the Ramah and the Baday, along with the Chochmas Adam
( Klal 48) and Aruch HaShulchan ( (Simen 95) all clearly indicate that washing
opposite types together, or one after the other, even in less than Yad Soledes water is
permissible only B’dieved, although this is speaking of washing them in the same water
either together or one after the other. Where the water is changed, as in our dishwashers,
it may be permitted L’chatchila. None of the Seforim deal with the container the dishes
were washed in, which is the concern with the dishwasher.
b- Nosen Ta’am Lifgam is utilized as a B’dieved as a result of a prohibition by the
Chachomim . (Yorah Deah Simen 103 & Simen 122 Sif 2)
There are two situations where this applies. One is a result of the utensils having been
unused for 24 hours. The other is the inclusion of a bad tasting substance. Soap would
clearly be included since the use of dishwashing liquid would render a bad taste to any
food in the dishwasher. However, this leniency is also applied only as a B’dieved. Had you
mistakenly washed a load of meat and dairy dishes together in your dishwasher a Rav might
permit the utensils and dishwasher depending upon several other factors. This is not a
L’chatchila situation which it appears to be the case in our original question.
This leniency is also connected to the following…
c- Ben Yumo/ Aino Ben Yumo. In the previous scenario the Rav will probably direct you to
refrain from using the dishwasher for another 24 hours. Nosen Ta’am Lifgam is usually
coupled with Aino Ben Yumo, which is also a B’dieved leniency, to strengthen the power of
the Heter. The Mishna Brura (Simen 452 Sif Katan 1) states that the Poskim do not permit Hagolo
unless the vessel is Aino Ben Yumo OR that there is 60 times the amount of water times the
volume of the vessels ( see ‘e’ below). Thus, one factor might be whether the utensils,
particularly Klei Rishon (utensils in which the cooking was done), as well as the dishwasher
itself, were Ben Yumo or Aino Ben Yumo.
d-Nosen Ta’am Bar Nosen Ta’am is another B’dieved leniency. Rav Moshe’s Tshuva mentions
this and gives it as the reason for requiring separate racks. He explains that the sides of the
dishwasher are never in direct contact with the dishes so only the racks are problematic. In
our mistake scenario, the Rav would probably be unlikely to utilize this. The dairy utensils
and leftover foods were resting on the rack and surfaces of the dishwasher, however,
everything was cold and imparted no flavors to those surfaces. We will see shortly what
occurs when the hot water is introduced.
e- Botel B’Shishim, nullified in 60 times the amount, will not come into play. There simply
will not be 60 times the amount of water as against the total volume of food, dishes,
silverware, pots and plasticware. In any event, it too is only B’dieved. The owner’s manual
for my dishwasher gives the following total amounts of water used. On “potscrubber” and
“heavy wash” the dishwasher uses 11.4 gallons of water. For “normal wash” 9.5 gallons.
“Light wash” uses 5.8 and “rinse only” 3.8 gallons. Clearly, using “normal wash” as an
example, we easily load a volume of over 1/60 of 9.5 gallons. This works out to only .125
gallons. 1/8 of a gallon is only a pint’s worth of other volume. Any food by itself, not
counting everything else, may not even be Botel since the water is sprayed )÷éìåç( around
the inside and at no time is 60 times the volume of water connected to all the food
particles. We needn’t worry about this since the soap has already rendered the food Nosen
Thus far, either the leniencies don’t apply or the applicable Heterim all operate only in a
post-facto situation and may not be used ab initio.
f- Yad Soledes Bo. When we speak of hot and cold, Halacha does not recognize an in-
between. Above Yad Soldes is hot, below Yad Soldes is cold. In Hilchos Shabbos the
temperature for Yad Soldes Bo is 105oF – 110oF. This is relatively not very hot. Your shower
water will be in that temperature range. In kashrus, Baday HaShulchan (
Simen 92 Sif Katan 151) gives a temperature of not less than 113oF. Since the home
dishwasher works off of the hot water tank and the industry standard sets a limit of 130oF
and actually suggests a maximum setting at 120oF, as does the dishwasher manufacturer, we
see that the water coming from the hot-water tank going into the dishwasher starts at just
above Yad Soledes. [Remember, for comparison, that the dishwasher in the Tshuvas Rav
Moshe that we began with used a water temperature of 180oF]. By the time the water
begins running, passes through many feet of copper pipes, through several feet of
uninsulated rubber hose and finally has to raise the room temperature of the dishwasher
walls and racks as well as all the utensils, clearly the water will be well below Yad Soledes.
This is good as it actually prevents a She’aila from happening. The problem occurs later in
the cycle. At the end, the dishes are clean but wet. There is no soap,leaving out the
leniency of Nosen Ta’am Lifgam. Now the heating element in the bottom comes on. The
temperature in the dishwasher goes above Yad Soledes [I actually got a reading of over
135oF and the mercury was plummeting from the instant I took the thermometer out of the
dishwaher] thus cooking the water on the dishes, racks etc.and filling the entire chamber
with steam. Any flavors absorbed in any surface will now impart those flavors to everything
else. People will wash utensils that were Klee Rishon (pots, ladles, corning dishes); or
knives that had cut Charif, in the dishwasher and the water clearly is not hot enough for
Hagolo. The only leniency which comes into play here is Nosen Ta’am Bar Nosen Ta’am. The
first load imparted a flavor to the racks and liner. The racks and liner, in turn, imparted
the flavor to the utensils in the second load. Sounds good. Problem is, this is only B’dieved.
One may not wash the second load relying on the Heter of N’t Bar N’t.
g- K’bol’o Kach Polto- Generally, the manner in which the original problem arose will be the
manner in which the solution can be effected. Since the temperature in the dishwasher
during the drying cycle reaches Yad Soledes Bo, any problem that occurs will be taken care
of by running the dishwasher through an empty cycle. This solution is almost always coupled
with waiting for 24 hours.
So far, we seem to be in a situation in which none of the above leniencies apply except as
Furthermore, having recently taken apart my own dishwasher to repair it, I found the vent
in the door, behind the plastic liner, to be full of all sorts of yummy things. The seals
around the door are never really clean either and food does occasionally get caught in the
water return pipes. This accounts for loads not coming clean occasionally. These probably
do not figure into the question for a host of reasons, but I don’t think they can be forgotten
in the total equation.
h- Minhag Yisroel Torah Hee- Regarding the permissibility of changing Milchig and Fleishig
utensils after they had been Kashered is an interesting question. Kashering, in effect,
renders any utensil Parve. What then prevents me from making my Milchig silverware
Fleishig or vice versa? The Minhag Yisroel (Magen Avvrohom Simen 509) is not to do this . Minhag is
so strong that nobody would permit this L’chatchila. It is not altogether clear that this
applies to a dishwasher, although the use of the drying element creates a cooking situation
perhaps making the dishwasher a real Milchig or Fleishig Keilee.
Above, we asked how the dishwasher differs from using the same sink to wash Milchig and
Fleishig dishes one after the other or by filling the sink with water and soaking things, or by
using the same plastic bucket? In effect, the questions are exactly the same minus the
heating element. It is actually rather difficult to create a Kashrus problem in the sink
without actually pouring boiling water over some utensils. Igros Moshe
( Yorah Deah Chelek 1 Simen 42)discusses this issue at length finding a high degree of
permissibility while finally deciding that a Ba’al Nefesh should certainly use separate racks
in the sink and take care that the water level does not back up to cover the dishes in the
sink. Yet, it is quite clear that Jewish women, for generations, [and, I imagine, the same
women who are relying on this Heter] have been exceedingly careful in these matters
going so far as to be careful of splashes from the sink walls. I’m quite sure that if any Rav
who permits the dishwasher, would go to his mother’s home and put a cold glass of milk
down on her Fleishig tablecloth, his mother would not be a happy camper at all [I’m being
nice about it] let alone if he placed a Milchig plate in with her Fleishig dishes in the Tepel .
Furthermore, mixed use of a utensil raises the issue of more than one person utilizing the
kitchen. The probability of a member of the family placing the wrong type of utensil into
the opposite load becomes quite high. It is this reason most women carefully color code
their utensils. The red bucket is Fleishig, the green one is Milchig [and you better not mess
up my kitchen if you know what’s good for you!]
i- Al Titosh Mi’Toras Eemecha- Shlomo HaMelech in Mishley, warns us to not depart from
the teachings of your mother. Since our mothers generally did not allow her sink, Tepel or,
if she had one, dishwasher to be used for both Milchig and Fleishig, it is surprising that any
Rav would permit this very easily.
In conclusion, this leniency may be a tad too lenient. Were the question to be, “May I eat
in someone’s home who does this?”. The answer might be, “Yes!”. But to operate one’s
kitchen on this basis as a L’chatchila is problematical at best. It simply crosses too many
borders with too many possibilities of error.Until, and unless, I see someone deal directly
with the problem of the hot steam filled interior of the
dishwasher, I will maintain that this one question seriously weakens any Heter. It weakens
the fabric of the rules in the kitchen leaving Kashrus wide open to leniencies in other areas
and destroying S’yug L’Torah.
TEMPERATURE READINGS IN A DISHWASHER AND THE HALACHIC IMPLICATIONS
To complete the research done on the use of a dishwasher for Milchig and Fleishig, I
determined that a record of the temperature during the various cycles would be necessary.
I was able to borrow a thermometer with a remote sensor to accomplish this.
I ran my dishwasher through one complete cycle. It is a 14 year old, portable, General
Electric. [To fully research this question would require running the same test on both
different, as well as, newer models.] The sensor was positioned in the center of the upper
rack. Temperature was noted at three-minute intervals. The starting temperature inside
the unit was 680F.
The hot water left the tap at 128F.
3 minutes = 92F
6 m= 103F
9 m= 105F
12m = 114F
15 m= 121F ( 49 C)
18m =1220F (50 0 C)
21m = 123F( 50 C)
24m =125F (51 C)
27 m=127F ( 52 C) 30
30 m=129F (53 C)
33m =1290F (53 0 C) 36
36m =1270F (52 0 C)
39 m=1300F (54 0 C)
42m =131F ( 55 C)
45m =129F (53 C)
48 m=128F (53 C)
51 m=129F (53 C)
54 m=131F (55 C)
57 m=127F (52 C) 60
60m =133F ( 56 C)
63m =144F ( 62 C) 66
66 m=147F (63 C )
69 m=159F ( 70 C)
72 m=164F ( 73 C)
75 m=169F (76 C)
78m =170F ( 76 C) 81
81m =170F (76 C)
END OF CYCLE
Note that soap was present immediately but the water did not reach Yad Soledes until
almost 12 minutes had passed. The soap was present for almost 40 minutes, close to half an
hour with the water above Yad Soledes. The final few minutes had a temperature only 200
short of Rav Moshe’s B’dieved Shiur of Hagala.
On this basis, one may conclude that any Ta’am on the racks started as cold, reached Yad
Soledes as Nosen Ta’am Lifgam because of the soap and continued to absorb/exude Ta’am
Lifgam for the duration of the cycles.
L’Halacha V’Lo L’Ma’aseh, we may therefore conclude that a dishwasher could, Lchatchila,
be used for both Milchig and Fleishig utensils perhaps only waiting 24 hours, or at least
overnight between the two types. B’dieved, even one right after the other would still be
I would still maintain that it may not be done on the basis of “Al Titosh M’Toras Imecha” as
well as “Minhag Yisroel Torah