An Inquiry Into Bubkes and Kozebubkes
Several authorities—including Anu Garg at A.Word.A.Day (cited by Hot Licks in a comment above) and Merriam-Webster's Online Dictionary assert that the original form of the bupkes family of spellings was bubkes—and that this word probably derives from the word kozebubkes.
Here is Garg's etymological note for bupkis:
From Yiddish, short for kozebubkes (goat droppings), from bub/bob (bean). Earliest documented use: 1937.
And here is the MW Online note for bubkes:
Origin of BUBKES: Yiddish (probably short for kozebubkes, literally, goat droppings), plural of bubke, bobke, diminutive of bub, bob bean, of Slavic origin; akin to Polish bób bean. First Known Use: 1937
But very few modern writers who use the term casually seem aware of that etymological connection. A Google Books search finds only one instance in which a novelist explicitly treats bupkis as a short form of kozebubkes. From Stella Suberman, The Jew Store (2001):
It was perhaps this last galling thought that got him to his feet. And, incredible as it was, even to him, he managed a smile and a thanks. Thanks for what? he asked himself. For bupkis, for goat shit (“Excuse me, children”), that's for what.
In contrast, we have two examples where a memoirist recalls a grandmother using some form of the term bupkis, which the author translates as “beans.” From Edward Cohen, The Peddler’s Grandson: Growing Up Jewish in Mississippi (1999):
The bread was made locally by bakers who, as my grandmother would say, knew bupkes (beans) about Jewish rye bread, and in truth it was a virtually tasteless beige bread that bore as little resemblance to the genuine article as would the concoction of a Brooklyn rabbi’s wife who might improbably try her hand at cornbread.
Stephen Jay Gould, Rocks of Ages: Science and Religion in the Fullness of Life (1999):
How could anyone look so deeply into the heart of biological causality and the history of life, and then offer us such a piddling dribble—bupkes, as my grandmother would have said—on the meaning of life and the ultimate order of things[?]
Are we to imagine that that these grandmothers intended to say “goat turds” but then blandly informed their grandchildren that the Yiddish term meant “beans”? It seems much more likely that, whatever the source meaning may have been, bupkis meant simply “beans”—literally or figuratively—in Yiddish/English from a very early date.
The earliest instance of bubkes that a Google Books search finds is from Abraham Cahan, “Fish, Fish, Living, Floundering, Jumping, Dancing Fish” (1899), quoted in Gateway to the Promised Land: Ethnic Cultures on New York’s Lower East Side (1994), which reports the following chaotic swirl of street peddler cries in a street scene on Manhattan’s Lower East Side at the end of the nineteenth century:
‘Fish! Fish! Living, floundering, jumping dancing fish! Pike, pike, pike! Take pity and buy the living pike! I cash clothes, I cash clothes! Bubkes, buy my hot, fresh bubkes\ Candy, ladies, finest in America! Only a nickel, a half-a-dime, five cents! Potatoes as big as your fist! A bargain in muslin! Buy a calico remnant—calico as good as silk, sweet little housewives!'
A similar scene occurs in Mike Gold’s semi-autobiographical novel Jews Without Money (1930):
There is no baby in there, but a big pot full of hot black-eyed beans. "Bubkes!" she wails in a sort of Chinese falsetto, "buy my hot, fresh bubkes!'
Gold was born on the Lower East Side in 1894. I can’t conceive of a street vendor trying to sell freshly prepared beans in a Yiddish-speaking neighborhood by referring to them as “goat turds” instead of using an uncontaminated word for “beans” (such as beblakh, cited by Leo Rosten), unless no potential buyers on the street were making the association with kozebubkes.
Another interesting comment in a memoir comes from Louis Lozowick (1892–1973), who was born in Ukraine but emigrated to the United States in 1906. From his memoir, published as Survivor From a Dead Age (1997):
If one wanted to make fun of a Jewish beard, it was likened to a goat's (tsigene berdl). To designate a small amount of money or income, one said it was just goat's droppings (tsigene bobkes). Perhaps it all goes back to scriptural authority.
Here it appears that the word tsigene (“goat”) was included in the phrase tsigene bobkes to mean “goat droppings” because bobkes alone would have been understood simply as “beans.”
Many authors provide an explicit “beans” translation for the Yiddish term. From A.J. Liebling, The Jollity Building (1962):
"The best you can get there," performers say, "is a chance to work Saturday night at a ruptured saloon for bubkis." "Bubkis" is a Yiddish word which means "large beans."
From Rachel Levine, Cyberyenta’s Old-Fashioned Wisdom for Newfangled Times (2001):
Bupkis—beans, but always meant to be something worthless. Like, “What will I get for all my hard work on this book? Bupkis!”
From Evan Morris, The Word Detective (2001):
The word you’re looking for is not butkis. It's bupkes (also spelled bubkis, bupkis, and bubkes), which is Yiddish for "beans," or, figuratively, "nothing, nada, zilch." But there's more to bupkes than just "nothing." When you say you got bupkes from a deal you brokered, for instance, it really means you got nothing when you should have gotten at least something if there were any justice at all in this world. All of which is a lot for one word to say, but Yiddish is good at that.
From Tom Dalzell, The Routledge Dictionary of Modern American Slang and Unconventional English (2008)
bupkes; bupkis noun nothing—used for expressing scorn at something deemed foolish or trivial US, 1942 From the Russian for “beans.”
From Herb Gardner, Conversations with My Father (1994):
”Gornisht”—in case it wasn’t clear to you—means nothing. “Gornisht with gornisht” being less than nothing. The only thing less than that is "bupkes," which is beans, and less than that is "bupkes mit beblach," which is beans with more beans. In Yiddish, the only thing less than nothing is the existence of something so worthless that the presence of nothing becomes more obvious.
From Leo Rosten, The New Joys of Yiddish: Completely Updated (1996):
bobkes, bubkes, bopkes, bupkes Pronounced BOP-kess to rhyme with “mop kiss,” or BUB-kiss to rhyme with “put this” or BAWP-kess to rhyme with “stalk-mess” or BUB-kess, to rhyme with pub mess.” Russian: beans. But Jews say “Bobkes!” not to designate beans (beblakh does that), but to describe, with considerable scorn, (1) something trivial, worthless, insultingly disproportionate to expectations. “I worked on it three hours—an what did he give me? Bobkes!” (I think “Bobkes!” more eloquent, because more harsh, than peanuts!”) (2) something absurd, foolish, nonsensical. “I’ll sum up his idea in one word: bobkes!”
Bobkes must be uttered with either scorn, sarcasm, indignation, or contempt. The expletive takes over where “Nonsense!” “Baloney!” or “Bushwa!” stops for a rest.
I know of no English word that carries quite that deflating, even bitter, aroma.
From Gene Blaustein, Anglish/Yinglish: Yiddish in American Life and Literature, second edition (1998):
BUHPkis n. Literally beans. But the word is also used to indicate something absolutely worthless, very much like our expression “not worth a hill of beans.” You might say, “What did I get for my effort—BUHPkis!” BUHPkis also works as an expletive, not as strong as “bullshit” but carrying the same connotations.
Claims of of an essential etymological connection between bupkis and kozebubkes are most common in reference works of the past thirty years or so. For instance, from Yetta Emmes, Drek!: The Real Yiddish Your Bubbeh Never Taught You (1998):
Bobkes (BUB-kis)—literally, goat turds. An absurd idea; an insulting offer, as in “What you're offering me is bobkes.”
One author asserts that the distinction between kozebubkes–derived bobkes and the nonscatalogical bobkes remains current in Yiddish, but I haven’t found any other reference that makes this argument. From Fred Kogos, From Shmear to Eternity: The Only Book of Yiddish You’ll Ever Need (2006):
Bobkes Small things, triflings, peanuts, nothing, worthless (lit., Excreta of sheep, goats)
Bubkes Beans; a mere bagatelle
Two fairly extensive treatments of bobkis are especially interesting. First, from Sol Steinmetz, Dictionary of Jewish Usage (2005):
bobkes. In Yiddish, this word is an interjection meaning 'rubbish! nonsense!,' derived from bobke, which means 'sheep or goat dung.' The word was borrowed from the Polish noun bobki, of the same meaning. Nevertheless, many have confused this word with the Yiddish words for beans, bobes, a confusion that has led Jewish English speakers to equate bobkes with the American English slang use of “beans,” as in He don’t know beans (attested in English since 1833), and I don’t care beans about that. So sentences like “I got bobkes for all my efforts,” “He made bobkes this year on the market,” and “Even if you win the case, the damages you’ll get will be worth bobkes” are examples of Jewish English usage[.]
And from David Gold, “A Yiddish-Origin English Word Misetymologized for at Least Sixty-six Years (Bopkes),” in Studies in Etymology and Etiology (2009):
The translation ‘nonsense!’ is too weak because it does not convey the moderate coarseness of the Yiddish word [bopkes]. Were English poppycock ‘nonsense’ to have retained the meaning of its Dutch etymon, namely ‘soft excrement’, it would be a denotationally and connotationally perfect English equivalent (that is, a moderately coarse slangism with an unveiled fecal allusion), but that meaning was not retained, as a result of which the English word is innocuous and thus would be inappropriate to render Yiddish bopkes!.
Presumably, if poppycock retained even a hint of the source word’s meaning “soft excrement,” ConAgra Foods would not have chosen it as the brand name for a line of candied popcorn. Similarly, it seems to me, Yiddish-speaking street vendors at the turn of the twentieth century would not have freely used bubkes to advertise their wares, and Yiddish-speaking grandmothers in the middle of the twentieth century would not have used the same term in conversations with their grandchildren unless, for them, the term meant only “beans.”