By: Rabbi Mordechai Mishanieh

1. What is the source of the commandment for mayim aharonim (the hand washing at the end of a meal)?

The Gemara explains that the sages instituted this requirement due to the danger posed by melah Sedomit, a potent salt used in early times to preserve food. The rabbis were concerned that a person might rub his eyes after the meal, forgetting about the salt stuck to the hands, and blind himself. Additionally, often a person’s hands are soiled after a meal, and it is inappropriate to recite a blessing with unclean hands. There are also Kabbalistic reasons for washing mayim aharonim.

2. Does this obligation apply today?

Although some authorities suggest that this obligation may not apply today, when melah Sedomit is not commonly used, the Yalkut Yosef writes that there might still exist salt with the same potency as melah Sedomit. Furthermore, the second reason for mayim aharonim mentioned above – the concern for cleanliness – certainly applies nowadays, as well, especially for those who always ensure to keep their hands clean. And, as noted by the Ben Ish Hai and Kaf Hahaim, according to Kaballah one should wash mayim aharonim even nowadays.

This obligation applies both to men and women.

3. When does one wash mayim aharonim?

One must wash mayim aharonim immediately before reciting Birkat Hamazon. One should ensure not to speak or make any interruption between the washing and the beginning of Birkat Hamazon. The Ben Ish Hai writes that the verses of Tehillim and other pesukim which are customarily recited before Birkat Hamazonmay be recited after washing mayim aharonim. One should also ensure not to allow a lengthy delay between washing and Birkat Hamazon; preferably, one should begin Birkat Hamazon within 15 seconds of washing mayim aharonim. Therefore, if many people are present at a meal, several mayim aharonim cups should be distributed so that everyone can begin Birkat Hamazon immediately after washing.  One who made an interruption between mayim aharonim and Birkat Hamazon should preferably wash again.

4. Are there other times when one obligated to wash mayim aharonim?

The Ben Ish Hai writes that one who weighs salt or touches salty food should wash mayim aharonim. This is also the opinion of the Or Lession and the Kaf Hahaim. The Yalkut Yosef, however, disagrees, and rules that one may rely upon those who maintain that melah Sedomit is no longer used and thus mayim aharonim is not required after handling salt or salty foods.

5. How should one wash his hands?

Water should be poured from a keli (utensil), only once on each hand starting with the right, up to the second joint of his fingers (and on the thumb, until the first joint). According to the Zohar, however, one must wash until his knuckles. If one has dirt on his hand above this area, he must wash there, as well. One should ensure to turn his fingers downward while washing so that the dirt will be removed. It is preferable to dry one’s hands before reciting Birkat Hamazon. One should avoid wiping his wet hands on his mouth after washing mayim aharonim.

6. What is recited when washing mayim aharonim?

Before washing, one should say “mayim aharonim hoba – mandatory after waters”.  Some have the custom to say “yahid verabim halacha herabim.” The BI”H writes that his grandfather sometimes relied on saying this as divrei Torah when there was not time to say other words of Torah during the meal before Birkat Hamazon.

7. What kind of water is suitable for mayim aharonim?

One should use only cold or room-temperature water, which is preferably clean and fit for drinking. Although there is no minimum required quantity of water, one should use enough water to ensure that his hands are cleaned. According to Kabbalistic teaching, one should use only as much water as is needed to clean his hands, and no more.

8. What should be used if no water is available?

If no water is available, one may use any type of beverage other than wine. If no liquids are available, then one should clean his hands as much as possible without water, and then wash his hands when water becomes available. It is important to ensure the availability of water for mayim aharonim before starting a meal.

9. What should be done with the “used” waters of mayim aharonim ?

The Gemara writes that one should not wash mayim aharonim over the ground, because a ru’ah ra’ah (wicked spirit) in the water can cause harm to those who step on it. It is therefore preferable to wash into a utensil and then discard the water in a place where people do not normally walk. If no cup is available, one may wash over an area where there are no pedestrians or into a sink, or into a used plate, provided that the plate is thoroughly washed afterwards. The utensil containing the water used for mayim aharonim should be moved off the table before Birkat Hamazon or at least covered.

10. What should one do if he forgot to wash mayim aharonim?

The Yalkut Yosef writes that if one realizes during Birkat Hamazonthat he forgot to wash, if his hands are clean, then he should wash his hands after finishing Birkat Hamazon. He must ensure not to speak, while he is in the middle of Birkat Hamazon.