Various, Popular Science Monthly (1887)
“ Sour ale and beer do not yield good vinegar. In the United States, cider vinegar has long held the preference, and, if the cider has been made from sound, sweet apples, the vinegar has a very agreeable flavor and color. The old-fashioned way which is followed by farmers in making vinegar is to set out-of-doors in the spring a barrel of cider which has become too "hard" and sour to drink, from the sugar partly turning to alcohol and acetic acid. ”
