Old Maid (unpopped corn kernel)

Unpopped kernels of popcorn has been called “old maids” since at least 1886. “Old bachelors” is a term that has sometimes been used for unpopped kernels, but the “old bachelors” version has never been as popular as “old maids.”
 
Other names for unpopped kernels include “widows,” “duds,” “pooped corn” and “flopcorn.”
 
 
Dictionary of American Regional English
old maid n
A kernel of popcorn that fails to pop. chiefly Nth, NMidl
1947 Bowles-Towle New Engl. Cooking 6, When the kernels begin to pop, cover the kettle. Shake rapidly until the kettle is filled with fluffy white kernels. Discard any old maids left in the bottom of the kettle.
1949 Sat. Eve. Post 21 May 36, All hands kept right on pitching in, and munching, until there was nothing left but a few unpopped kernels derisively known as old maids.
1967

FW Addit swWI, “Old maids”—kernels of corn that do not pop and are left in the bottom of the pot after making popcorn.
1970 DARE File seWI, Old maids—the unpopped kernels of popcorn that are left in the popping pan. I’ve heard two different people from Milwaukee say this.
   
27 April 1886, San Francisco (CA) Bulletin, pg. 4:
A popcorn man in town calls those kernels that do not pop and that cannot be popped, “old maids.”—Chicago Journal.
 
Google Books
Emma Lou—Her Book
By Mary M. Mears
New York, NY: Henry Holt and Company
1896
Pg. 15:
“That’s my case too, Miss Hanson, for I’m particularly fond of popcorn, especially these crispy ‘old maids,’” he answered, laughing, and then added:
 
“How appropriate that they should be called ‘old maids,’ for have not the natural hopes of both been blighted?”
 
“Oh no,” I returned. “Most old maids are old maids because they refused to have their hopes blighted.” His eyes were full of laughter, and I went on. I don’t know what possessed me.
 
“I think it would be much more appropriate, Mr. Benson, if they were called old bachelors.” I remembered the riddle.
 
“Why?” he asked.
 
“Oh, because neither ever popped,” I answered.
 
He looked at me a moment and then threw back (Pg. 16—ed.) his head and laughed, and I, I wished I had never said it. What did he think of me? A teacher, too! He soon recovered himself and said, “Miss Emma, your logic won’t quite hold, for it is a lamentable fact, owing to the hardness of the hearts of some of your sex, that men have popped, and still remain single. How are you going to reconcile that with your statements?”
 
I did not wish to discuss the subject any further, but I said in a low voice, “These half-popped kernels will represent that class.”
 
“Very well, Miss Emma Lou, I surrender, henceforth the ‘old maids’ are ‘old bachelors,’” he said.
     
Google Books
The Adventures of Bobby Orde
By Stewart Edward White
New York, NY: Grosset & Dunlap
1911
Pg. 265:
Always were some kernels which had refused to expand. “Old Maids,” Bobby called them.
 
9 April 1916, Kansas City (MO) Star, section 2, pg. 4B:
How to Pop Corn.
From Farm and Fireside.
The Department of Agriculture has laid down rules for popping corn so you can get the largest possible amount of buttered crispness and almost no “old maids.”
 
Google Books
The Custard Cup
By Florence Bingham Livingston
New York, NY: George H. Doran Company
1921
Pg. 241:
As Mrs. Penfield went back into the house, Lettie came dancing in from a trip to the yard to feed the popcorn old maids to Bonnie Geraldine.
 
Google Books
Popped Culture:
A Social History of Popcorn in America

By Andrew F. Smith
Published by Univ of South Carolina Press
1999
Pg. 40:
Haskin’s Christmas days started off with popcorn cereal composed of ground “old maids and the old bachelors” with sugar and cream. Old maids and old bachelors were the kernels that did not pop after exposure to heat. (Today these terms have been deemed politically incorrect; the proper substitutions are “duds,” “unpopped kernels,” “pooped corn,” or “flopcorn.”)