Does anyone know the origin of the custom to spit in Aleinu after the words שֶׁהֵם מִשְׁתַּחֲוִים לְהֶבֶל וְלָרִיק?
Where did it start? And in which seforim is it mentioned?
I have seen in the sefer Hayom Yom - 9 Tevet that the reason for this minhag is that speech stimulates saliva, and we do not wish to benefit from this saliva, but I'm curious to know about how/where this minhag started.
Also, is this minhag practiced today apart from Chabad?
The oldest reference to this tradition that I am aware of is the Taz ("Turei Zahav"), by David haLevi Segal, 17th c.
הלוחש על המכה או על החולה ורוקק ואחר כך קורא פסוק מן התורה אין לו חלק לעוה"ב
One who whispers over a wound or over a sick person and who spits, and who then recites a verse from the Torah has no portion in the world to come.
- Yoreh Deah 179:8
ורוקק ואח"כ קורא כו'. הטעם דכיון דמזכיר שם שמים על הרקיקה הוי בזיון ח"ו ועל כן אין להקשות ממה שנוהגין ברקיקה קודם ואנחנו כורעים דשם הכל יודעין שהרקיקה היא לבזיון הגילולים של עובדי כוכבים והיא כבוד שמים שמזכיר אח"כ
... and who spits, and who then, etc: The reason is that since he mentions the name of heaven after spitting it is a disgrace, God forbid. Therefore, one need not find problematic our custom of spitting before "and we bow" [ve'anachnu kor'im, in Aleynu Leshabeach], for there everybody knows that the spitting is meant as a degradation of the idols of star worshippers, but that it is the honour of heaven that we are mentioning afterwards.
- Taz, ibid., (ס"ק ה).
I know of no text that gives a specific reason as to why it's done, but it is practised outside hasidic circles as well. It is mentioned, for example, in Siddur Vilna, p138:
ונוהגין לרוק בשעה שאומר שהם משתחוים להבל וריק וכו
We have a custom to spit when one says, "For they prostrate themselves to idleness and emptiness", etc.
I have heard it said that this is because "and emptiness" (וריק) looks similar to "to spit" (לרוק), but this is less of an origin story than it is a justification. In any case, to quote Hamlet, this may be a custom more honoured in the breach than the observance.
This minhag is mentioned much earlier than the Taz, in the sefer עמק ברכה, by Rav Avraham Horowitz (1550-1615), in a gloss by his son, the Shelah Hakodosh:
Some people are accustomed to spit during Aleinu, but they don't know why they spit, and the majority of people nowadays do not understand Loshon Hakodesh at all and spit when they say "and we bow down..." which is totally forbidden. Also, the Aleinu prayer was composed by Yehoshua bin Nun at a time when there were idol worshipers around, unlike nowadays. Also, it is a very dangerous practice because the nations that we live amongst might think the phrase "ככל המונם" refers to them, and as we just explained, Yehoshua composed the prayer for his times. Therefore, it is fitting to protest against those who do this.
The Chabad (intellectual) explanation is as you'd mentioned, "not to benefit from the saliva generated while talking about idol worship."
I'd presume a more basic explanation would be to add stress: "they bow to these worthless idols and pray to a god that can't save them. Ptooey to that!"
It's said that not too far in the past, many synagogues with an "old world" flavor to them would have spittoons! My sense is today's sense of American decorum (and hygiene) has mostly done away with this; at least in relatively modern, non-Hassidic circles.
In maseket Sotah 40a the last Tosafos on the page discusses spitting in a shul in regards to the Gemara's discussion of what is appropriate conduct in one's home. I have not learned the Taz inside quoted above but I think that the root source for the Taz would be this Gemara.
As a minhag it is mentioned in Sefer Minhagim Chabad, Breslov, and, as mentioned above, is not exclusively a minhag of chassidic circles.
Rabbi Barry Freundel writes in his book Why We Pray What We Pray: The remarkable history of Jewish Prayer, (Note: I do not have access to his sources) that the custom has been documented since the 15th century and during the 17th century the congregation would spit to show government informers that no one was saying the censored part of the prayer. Sounds interesting and I would like to see some sources on this from his book.
