By Rabbi Yair Hoffman

There is a controversy brewing in regard to dishwashers – that can be viewed as a possible divide between the Chareidi community and other religious communities in Eretz Yisroel in.  There is also a 50 year old salmon recipe that may possibly help determine which side may be correct.

Just as an aside, before we begin – there is now a trend in many communities to install two dishwashers – both, yes, fleishig and zero milchig!   Practitioners explain that it is a huge time and money saver.  How so? You fill them both up on a Motzai Shabbos and then put them away Sunday morning.  Easy-peezy.

But let’s get back to the halachic discussion

In Igros Moshe Yoreh De’ah (vol. 2, #28, 1964), Rav Moshe Feinstein zatzal provides three explanations as to why one could possibly be permitted to get by with a single dishwasher and two separate racks for both milchigs and fleishigs used during separate times.

One of the reasons was that dishwashers do not have an internal heating mechanism and would be considered a Kli Sheini and not a Kli Rishon.  This author was once on a plane flight and sat next to his esteemed son-in-law, Rabbi Dr. Moshe Tendler zt”l on a flight from Los Angeles to New York.  Rabbi Tendler, at first, stated that they do not have internal heating mechanisms, and that his shver had consulted with him on this very matter – not once, but twice.  I then proceeded to draw the schematic of a few different models.  Rabbi Tendler zt”l then responded that if that is the case, then the halacha would need to be re-exaimed.

Rav Feinstein quoted the Rama (YD 95:3) who rules that the very same basin of water could be used for cleaning meat and dairy dishes consecutively. Rav Moshe explained that nosain ta’am bar nosain ta’am, would render it such that the ta’am of the meat and dairy would be lessened – once one type of dish is removed.  This Rama, however, is dealing with a kli sheini and not a kli rishon. Also, there is almost always b’en – solid fleishigs in the trap or drain that is fully edible. 

Another point Rav Moshe zatzal made was that the huge amount of water would make for bittul b’shishim, a nullification in a 60:1 ratio.  This too, does not account for the minimum amount of wather that comes in contact with the meat that is in the trap and would send ta’am upward since it is piping hot.

The modern communities in Eretz Yisroel have extended these arguments even more and do not even require separate racks as Rav Feinstein zatzal had argued.

Rav Moshe continued the discussion a bit eight years later in Teshuvah #29 (1972) as well as in YD #43,  YD III #28 and #29. He explains that soap or detergent is considered a davar hapogaim, and while that may be a mitigating factor the soap may not pogaim the meat in the trap, as the soap is often washed away in a manner not too different from strawberries and other vegetables that the Kashrus agencies are now requiring. The mitigating factor of nosain ta’am lifgam after 24 hours does not apply to real b’ain.

Rabbi Yehuda Spitz shlita (an outstanding Talmid Chochom and Posaik) in his Ohr Samayach’s Insights into Halacha, cites a number of Poskim who disagreed with Rav Moshe’s heter and mitigatim factors – for a number of reason. They are: See Shu”t Ba’er Moshe (vol. 7, 60), Shu”t Beis Avi (vol. 2, 93), Shu”t Avnei Yashpei (vol. 3, 71), Yalkut Yosef (IV”H vol. 3 pg. 491, s.v. ulam), Badei Hashulchan (Y”D 95, 81; Biurim pg. 309, s.v. u’linyan), Pischei Halacha (English version ppg. 258 – 262), Kitzur Shulchan Aruch (Pfeiffer, on BB”C vol. 2, Kuntress HaBiurim 6), Kovetz M’Beis Levi (vol. 1, HaKashrus HaMitbach pg. 30, 7, footnote 6), HaKashrus (Ch. 1, pg. 75 -76), Kashrus V’Shabbos B’Mitbach HaModerni (pg. 114), Ohel Yaakov (on IV”H 1st edition pg. 296 – 297, 26, footnotes 52 & 53).

Two more thoughts:  In the 1960’s and early 1970’s, frum American families were still relatively poor and were not in a position to afford two dishwashers or significant household help.  Rav Moshe zatzal looked out for Klal Yisroel as much as possible – something that should be taken more into account even nowadays. 

But the second thought goes back to 1975.  An actor who played villians went on national television with a recipe as to how to “cook salmon” in, yes, a dishwasher.

What follows is just such a recipe.  The purpose of printing it is to show that dishwashers are clearly a kli rishon.  There are two main types of the internal heating mechanism: 1]An exposed one – generally a visible coil at the bottom of the tub, similar to an oven element. They are common in many American-brand budget and mid-range models (GE, Whirlpool, Maytag, Amana). These heat up the wash water and also do a “heated dry” by radiating heat after the wash cycle. 2] Those with hidden/concealed heaters — they are built into the base or integrated into the circulation pump. Brands like Bosch, Miele, and many European-style dishwashers use this approach. They heat the water but typically rely on condensation drying rather than a hot exposed element, which is gentler on plastics and are more energy-efficient.

The Recipe

Begin by pulling out two pieces of aluminum foil, each roughly 16 inches long. Lay your salmon fillet in the center of the first sheet and sprinkle it generously with garlic salt and lemon pepper. Once seasoned, place the second sheet of foil directly on top.

Carefully press the edges of the two sheets together and fold them over several times, crimping tightly all the way around. The goal is to create a fully sealed packet that hugs the fish closely and prevents any water from getting inside.

To cook it, position the foil-wrapped salmon on the top rack of your dishwasher and run a standard wash cycle. DO NOT ADD DETERGENT!  The heat generated during the normal cycle is intended to cook the fish. When the dishwasher finishes, open the door and take note of the smell. If the foil packet was sealed properly, the interior of the dishwasher should smell as it normally does, without any trace of fish.

Remove the packet, carefully unwrap the salmon, and transfer it to a plate. You may see a bit of liquid inside the foil — that’s simply moisture released during cooking, assuming the seal held. Before serving, check that there is no scent of detergent on the fish. For safety, insert an instant-read thermometer into the thickest part of the fillet and confirm it has reached an internal temperature of 145°F. If it has, the salmon should be tender, moist, and ready to eat — unconventional method notwithstanding.

Potential Concerns

However, several safety issues should be considered. If the fish fails to reach the USDA-recommended minimum internal temperature of 145°F, there is a risk of foodborne illness. Dishwashers vary widely in temperature output and cycle duration, so results are inconsistent. Additionally, if the foil packet is not perfectly sealed, water and detergent can penetrate the wrapping, contaminating the food. For these reasons, appliance manufacturers strongly advise against using dishwashers for cooking, as they are not engineered for food preparation.

The author can be reached at [email protected]