Entry in progress—B.P.
     
Wikipedia: Applejack (beverage)
Applejack is a strong alcoholic beverage produced from apples, popular in the American colonial period.
 
Applejack was historically made by concentrating hard cider, either by the traditional method of freeze distillation or by true evaporative distillation. The term applejack derives from jacking, a term for freeze distillation. The modern product sold as applejack is no longer produced using this traditional process.
 
Freeze distillation is a low-infrastructure mode of production compared to evaporation distillation. Apples and applejack have historically been easy to produce in small quantities. Hard apple cider was an important drink in the colonial and early years of the United States, particularly in areas without access to clean water, but was often considered insufficiently palatable and bulky to store. Rather than consume an alcoholic fruit beer, the cider harvested in the fall was often separated in the winter via freeze distillation, by leaving it outside and periodically removing the frozen chunks of softer cider to a separate container, for consumption or further fermentation. From the fermented juice, with an alcohol content of less than 10%, the concentrated result contains 30-40% alcohol, is slightly sweet and usually tastes and smells of apples. However, freeze distilling concentrates all of the alcohol by-products of fermentation – including methanol and fusel alcohols as well as ethanol. Distillation by evaporation can separate these since they have different boiling points. With easy availability of grain, metal stills, clean water, and eventually pasteurization starting in the mid 19th century, cider and applejack were gradually displaced by other beverages and liquors.
 
Free Merriam-Webster Dictionary
ap·ple·jack noun \-ˌjak\
Definition of APPLEJACK
: brandy distilled from hard cider; also : an alcoholic beverage traditionally made by freezing hard cider and siphoning off the concentrated liquor
First Known Use of APPLEJACK
1816
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(Oxford English Dictionary)
applejack n. 
(a) N. Amer. a strong spirit made from apples; apple brandy;  (b) a sweet made from apples baked in pastry; spec. (chiefly E. Anglian) an apple turnover.
1816 ‘Old Scene Painter’ Emigrant’s Guide 30   A partial distillation is also made from apples‥called Apple-Jack.
1823 E. Moor Suffolk Words,  Apple-jack, sugared apples, baked without pan, in a square thin piece of paste, with two opposite corners turn’d over the apple.

30 June 1795, Dunlap and Claypoole’s American Advertiser (Philadelphia, PA), pg. 2 ad:
French Brandy and Apple Jack by the barrel
 
11 May 1810, The Democratic Press (Philadelphia, PA), pg. 2:
Sir I send you’s few lines to inform you that there is two Hogsheads of tobacco, and two Hogsheads of apple jack, that hath been taken up in the Bay and expect that it came out of the New York schooner that was lost in the bay.
 
Google Books
The Emigrant’s Guide, or a picture of America:
Exhibiting a view of the United States, divested of democratic colouring : taken from the original now in the possession of James Madison, and his twenty-one governments : also, a sketch of the British provinces, delineating their native beauties and superior attractions
By Old scene painter
London: printed by W. Clowes, for W. Simpkin and R. Marshall
1816
Pg. 30:
An inferior quality of spirits is likewise distilled in the state of Massachusetts, known by the name of Yankee rum; a partial distillation is also made from apples and peaches, the produce of the former is called Apple-Jack, and that of the latter Peach-brandy.
 
16 February 1818, Washington Whig (Bridgeton, West New-Jersey), pg. 4 ad:
Country Gin of a superior quality,
Apple Jack, ...