Consumer magazine Which? has hit out at the quality of most big brand wines labelling them "mediocre" and "disappointing" after a blind tasting session by a panel of wine experts.
According to the report, one judge described the experience as "shocking" while another had trouble finding even "a little bit of character and balance".
In the white wine section, Piat d'Or scored just 8.3 from 20, while others including Jacob's Creek, Blossom Hill, E&J Gallo, Kumala, Stowells and Penfolds all averaged less than 11.
In the red division, Banrock Station Merlot 2003 hit rock bottom with an average score of seven.
Four other wines including Rosemount Diamond Label Merlot 2002, Rosemount Diamond Label Shiraz, Cabernet Sauvignon 2004, Lindemans Bin 65 Chardonnay 2004 and Hardys Nottage Hill Chardonnay 2003 all scored high on taste but low on value.
The only wine to merit a Best Buy was Cawarra Cabernet Merlot 2004, scoring 13 and representing good value at £4.99.
"The majority of the big brand names we tasted were mediocre," said Which? editor Malcolm Coles. "And we're not talking about bottles that cost three quid either some of them sell for £6 or £7. At least they are reliable, though. Just one bottle in the whole batch we tried was faulty."
Emma Chamberlain, marketing manager at Piat d'Or and Blossom Hill supplier Percy Fox, told the Morning Advertiser sister paper OLN: "Given the low scores for all of the highly successful brands in the selection, I have some questions around the methodology.
"It seems this tasting was set up by wine experts for wine experts, without perhaps the due consideration for price points nor what tickles the vast majority of consumers' tastebuds."