The phrase a sniff of the barmaid’s apron and its variants denote a drink of alcohol.

This phrase is especially used of an initial drink taken by someone (e.g. a young person) who is particularly susceptible to the effects of alcohol.

These are, in chronological order, the earliest occurrences of the phrase a sniff of the barmaid’s apron and variants that I have found:

1-: From the account of a mock-trial, held during a charity event at Oakham, in Rutland, published in The Grantham Journal (Grantham, Lincolnshire, England) of Saturday 6^th July 1929:

The prisoner, asked if he wished to say anything, stated: […] Even if I am on the dole I am only a working-man, and when I went wi’ some of me pals to the Cup final at Egleton and got in wi’ a crowd of Bolshies, they told me they’d find me in ale and baccy for the rest of me life if I would chuck a cabbage at the King’s head. I may add, me landlord, I mean your Worship, as ’ow I ain’t ’ad as much as a sniff of a barmaid’s apron from ’em.

2-: From The Sea-green Grocer, by Jaspar Power, published in Good Morning: The Daily Paper of the Submarine Branch (London, England) of Wednesday 19^th April 1944:

“Butler and I found him lying on the dock road, absolutely unconscious, with a man who claimed to be a mission superintendent. This man told us that the fellow on the ground belonged to the ‘Antipas,’ so we naturally brought him aboard, thinking he’d had a sniff of the barmaid’s apron.”

3-: From The Vancouver Sun (Vancouver, British Columbia, Canada) of Saturday 1^st February 1958:

Court to Get Tough With Teen Drinkers
‘They’re High on Sniff Of Barmaid’s Apron’

North Vancouver—Magistrate A. D. Pool threatened Friday to deal with drinking teen-agers “so severely they’ll be absolutely scared of being caught with a bottle on the hip.”
He said he was tired of hearing drunkenness cited as an excuse for juvenile misdemeanors.
Youthful drinkers assume a state of inebriety regardless of how little alcohol they’ve consumed, he said. “They’d feel high on one sniff of the barmaid’s apron,” he added.

4-: From No wild evenings in the drivers’ favourite inns, published in The Birmingham Daily Post (Birmingham, Warwickshire, England) of Monday 13^th January 1964:

We had been sent out to find a typical country pub, frequented by lots of motorists, and to watch what drinking went on, especially drinking before driving, about which so much has been heard in connection with Christmas and New Year road accidents.
[…]
The second pub on our list looked very promising. The car park was full. So, too, was the lounge, with a laughing mixture of young men and women at the bar […].
[…]
In the overflow bar drinking was at a slightly higher pace. But of three friends, two were drinking beer and one, the driver, bitter lemon.
That, inevitably, started a conversation on our theme of the night . . . drinking and driving.
“The trouble is the difficulty you have in gauging different people’s capacities,” someone said. “Some types will not change with a couple of pints, others, well, give them a couple of wine gums and a sniff of the barmaid’s apron and they’re a menace.”

5-: From a letter published in the Walsall Observer and South Staffordshire Chronicle (Walsall, Staffordshire, England) of Friday 20^th October 1967:

A sallow, weedy youth of 19 may feel his head reel after a couple of half-pints and a sniff of the barmaid’s apron, while a 16-stone steelworker would be perfectly capable after six or more pints of beer. Who is the greater danger on the road?

6-: From an article about a Ceylonese restaurant that had to close because of hooliganism, published in the Neath Guardian (Neath, Glamorgan, Wales) of Thursday 4^th September 1969:

True it is that there is far too much of this loutish conduct going on in our streets at night. Most of us are subjected to foul, obscene abuse from youngsters who have had a sniff of the barmaid’s apron at a pub or a club.

7-: From the column Tuesday Tee-time, by Mark Wilson, published in the Evening Standard (London, England) of Tuesday 20^th April 1971:

Peter Alliss ¹ […] has really rocked the PGA ² image in public.
Alliss has alleged unruly behaviour—worthy of £250 fines by some players during the Italian Open. He writes: “To me the whole horrid business is quite inexcusable.
“The people concerned were not all young boys away from home for the first time . . . carried away by a sniff at the barmaid’s apron. No. They were people who have been entrusted with power and position.”

¹ Peter Alliss (1931-2020) was a British professional golfer.
² PGA is the abbreviation of Professional Golfers’ Association.

The phrase is apparently used figuratively in the following from the Observer (London, England) of Sunday 11^th September 1988:

This summer Britain’s sports officials have surpassed themselves in emphasising their legendary disengagement from the realities of this world.
In athletics, the treatment of our internationally admired Olympian, Sebastian Coe, has been a disgrace. Initially spurned, he was then tantalised with a series of fatuous face-saving schemes involving, at various times, the bending, rewriting or misreading of the rule-book.
Cricket has been even worse. Beginning in May, the selectors took one sniff of a barmaid’s apron and proceeded to run through four different captains, a whole coach-load of players and then contrived the imminent cancellation of the Indian tour. Knowing full well they were visiting a country that takes apartheid seriously, they chose a side packed with players of recent South African experience and, to lead them, a man already contracted to play for Western Province.

The British singer, songwriter and musician Peter Hook (Peter Woodhead – born 1956) used the phrase figuratively in the sense of foretaste in an interview with Martin Bandyke, published in the Detroit Free Press (Detroit, Michigan, USA) of Sunday 8^th September 2013:

QUESTION: After the death of Ian Curtis ³, did you and the rest of the surviving members of Joy Division make an immediate decision to continue under the name New Order?
ANSWER: Yeah. In England we say “we had a sniff of the barmaid’s apron.” I think you could safely say we had seen a better world, a more interesting world for ourselves, and whilst a curtain had been drawn over it when Ian died, we still thought we had something to give musically, artistically, creatively, however you want to put it.

³ The British singer, songwriter and musician Ian Curtis (1956-1980) was the lead singer and lyricist of the rock band Joy Division.