Green’s Dictionary of Slang

very cheap ale.

1576		U. Fulwell Art of Flattery 6th dialogue 27: This thy description of dagger ale augmenteth my thirst vntill I taste thereof.
1603		R. Mavericke Three treatises religiously handled n.p.: Drink, the drunkards must needs haue, only fit for drunkards; and that is such dagger-Ale (as they call it) as almost no ciuill honest subiect can abide to drinke it; by reason it is so raw fulsome and headie.
1649		John Taylor Wanderings to see Wonders of West 24: There was [...] strong beer and dagger ale, land flesh and sea fish in plenty.
1654		J. Mennes Recreation for ingenious head-peeces n.p.: Whilst dagger-ale barrels / Bear off many quarrels, / And often turne chiding to laughing.
1675		J. Ogilby Æsopicks 87: Then spake the Jugg; Know, Fool, I am not built / For Dagger-ale, and Commoners, a Tilt; / Which mild at first, turn Vinegar grown old, / Too sharp for Peers, and with their King too bold.