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.
[UK]N. Culpeper Culpeper’s school of physick 296: [T]he head is light, and akes, full of fantasies, and divers times some be so sopited, that the Maltworm playeth the devil so fast in the head, that all the world runneth round about on wheels.
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.