Green’s Dictionary of Slang

(Aus./N.Z./S.Afr.) wine sold in 2.5- or 5-litre (4.5–9-pint) containers, placed in a cardboard box.

1987		Canberra Times (ACT) 31 Dec. 12/6: [M]ost of the drop in sales is in the cask market, chateau cardboard, considered the bread and butter of the wine industry.
1989		J. Hibberd Memoirs of an Old Bastard n.p.: [...] insipid stock, fake tomatoes from Queensland, an absence of veal knuckles, Chateau Cardboard wine and pseudo-Cognac.
1999		G. Seal Lingo 133: The problems associated with over-proof and downright dangerous concoctions are also numerous in colloquial speech: [...] red ned; bombo; chateau cardboard (all terms for poor quality wine).
1999		www.dinkumaussies.com 🌐 The soft pack or bag-in-box we have come to know and take to our hearts as the cask, containing our favourite tipple of ‘Chateau Cardboard’.
2003		McGill Reed Dict. of N.Z. Sl. 44: chateau cardboard/chateau de cask Cheery 1980s terms for cheap bulk wine in cardboard box.
2003		Aus. Word Map 🌐 chateau de cardboard [In W.A.] cheap cask wine: We’ve got beer and some Chateau d'Cardboard.