Green’s Dictionary of Slang

a particularly strong malt beer.

[1685		G. Meriton In Praise of York-shire Ale 3: Twist and Old Pharoh, and Old Hoc].
1720		in D’Urfey Pills to Purge Melancholy VI 225: If Belly full of Ale doth grow, / [...] / Old Pharoah will not let you go.
1737		B. Franklin ‘Drinkers Dict.’ in Pennsylvania Gazette 6 Jan. in AS XII:2 92: They come to be well understood to signify plainly that A MAN IS DRUNK. [...] He’s contending with Pharaoh.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. n.p.: pharoah very strong Mault-Drink.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1839		(con. 1715) W.H. Ainsworth Jack Sheppard (1840) 104: Don’t muddle your brains with any more of that Pharaoh.
1859		Matsell Vocabulum 68: pharo Strong male liquor.