Green’s Dictionary of Slang

malt n.

1. as a constituent of beer, used in phrs. indicating drunkenness, below.

2. (UK Und.) tea.

[UK]P. Colquhoun Commerce and Police of the River Thames 95: Cant phrases are in use for the purpose of holding criminal intercourse [...] Tea is known by the appellation of Malt.

In derivatives

malty (adj.)

drunk; thus personnified as Mr Maltby.

[Scot]Caledonian Mercury 14 Oct. 4/2: Toasts and bumpers had so often gone round that Mr Maltby was getting on board, but Sir Oliver’s resplendence conducted the company home before twelve in good order.
[Ire]‘A Real Paddy’ Real Life in Ireland 99: Going to bed malty with his clothes on.
[UK]‘Bill Truck’ Man o’ War’s Man (1843) 146: His fondness for larking and mischief when he’s malty.
[UK]Crim.-Con. Gaz. 7 Dec. 295/1: There is no harm in Jas. Scott going to cricket, but why did he get so terribly malty.
[Aus]Bell’s Life in Sydney 27 Dec. 1/5: [...] picked up by the traps for getting malty and have the next morning to shell out to the beak five or ten of the queen’s images.
[UK]Punch XIII 213/1: Malty is indicative of the state of the Fast Man when under the effect of too much ‘malt’.
[UK]Flash Dict. in Sinks of London Laid Open.

In compounds

maltpie (n.)

alcohol.

[UK]T. Heywood Edward IV (1874) I 11: See how Saint Katherines smokes; wipe, slaues your eies, And whet your stomackes for the good mault pies.
maltworm (n.) (also malt-bug) [play on SE maltworm, a malt-infesting weevil; in cits. 1550, 1575 note joc. troll-the-bowl, a tippler, carouser]

a heavy drinker.

T. Chaloner (trans.) Erasmus Praise of Folie (1509) 25: [O]lde men, rather good maltwormes, than women haunters, who contrarie to my supposicion will putte theyr greatest felicitee in tipling, and good fare.
[UK]Skelton in Works (1843) I x: The tears ronne downe her cheke / Then dothe she troule To me the bolle As a goode malte worme sholde .
[UK]‘Mr. S’ Gammer Gurton’s Needle in Whitworth (1997) II i: Then doth she troll to me the bowl, Even as a malt-worm should.
[UK]W. Harrison Description of England 150: It is incredible to say how our malt-bugs lug at this liquor .
[UK]Nashe Prognostication in Works II 147: If violent death take not away such consuming mault worms [F&H].
[UK]‘Mary Tattle-well’ Womens sharpe revenge 173: There is no learned Pot-leech or Renowned Malt-worme that is worthy to hold the candle to an English Drunkard.
Austin Dobson Poems on Several Occasions II, 209: ‘The Malt-worm’s Madrigal’ [Title] [F&H].

In phrases

do malt (v.)

to drink beer.

[Aus]Argus (Melbourne) 6 Jan. 6/3: ‘Modern Fast Conversation’ [...] He does not drink beer, but ‘does malt,’ or (the nasty follow) ‘takes a drain’.
have malt above the meal (v.)

(Scot.) to be drunk.

J. Kelly Scot. Proverbs 320: The Malt’s above the Meal with you. That is, you are drunk.
[Aus]Bell’s Life in Sydney 14 Mar. 2/5: Mary M’Cann, a natty little piece of property, made her bow for taking ‘her malt above the meal’.
M. Porteous Souter Johnny 10: He was a sturdy stalwart chiel, Fond o’ his maut aboon his meal.
have malt above the water (v.) (also have rum above the water)

to be drunk.

[UK]J. Ray Proverbs (2nd edn) 87: Proverbiall Periphrases of one drunk. He’s disguised [...] The malt is above the water.
[US]B. Franklin ‘Drinkers Dictionary’ in Pennsylvania Gazette 6 Jan. in AS XII:2 92: They come to be well understood to signify plainly that A MAN IS DRUNK. [...] The Malt is above the Water.
[Aus]Bell’s Life in Sydney 28 Feb. 3/2: Elizabeth Stevens [...] was charged with taking her rum above the water, and shewing off in the police office.
have malt above the wheat (v.)

to be drunk.

[UK]J. Heywood Proverbs I Ch. xi: Soft fire maketh sweete malte. [Ibid.] 25: Malt is aboue wheate with him, market men saie.
Cogan Haven of Health (1612) 217: Take good heede that malt be not aboue wheate before your parte.
N. Breton Fantastickes B3: Haruest. Malt is now aboue wheat with a number of mad people.
[UK] in Ebsworth Roxburghe Ballads II 95: Men will call for it [i.e. tobacco] when malt’s above wheat.