Cheap plonk has the same effect on the palate as wine costing up to six times as much, a psychological taste test has shown.
The study suggests many people are merely paying for the label when they splash out on that "special" bottle.
A total of 578 members of the public took part in the "blind" taste challenge during the Edinburgh International Science Festival.
They were offered a range of red and white wines costing less than £5 and other vintages priced between £10 and £30.
Participants were asked to say which were cheap and which were expensive.
Purely by the laws of chance, they should have been able to make a correct guess 50% of the time.
This was exactly the level of accuracy seen, demonstrating that the volunteers could not distinguish between wines by taste alone.
Psychologist Professor Richard Wiseman, from the University of Hertfordshire, who led the research, said: "These are remarkable results. People were unable to tell expensive from inexpensive wines, and so in these times of financial hardship the message is clear - the inexpensive wines we tested tasted the same as their expensive counterparts."
The wines tested included cheap and expensive brands of Sauvignon Blanc, Pinot Grigio, Chardonnay, Merlot, Rioja, Shiraz and Claret.
Two Champagne labels costing £17.61 and £29.99 were also compared.