It does not appear that the taste of his wine gave Kurniawan away, even though he mixed some fine wines with cheaper ones.
Instead, collectors became suspicious when they noticed some labels had spelling errors or were for vintages that did not actually exist for the date given on the bottle.
Michael Egan, the expert hired by Koch, testified that 19,000 counterfeit labels of 27 of the world's best wines had been found at Kurniawan's house. "There's going to be a lot of wines to be cleaned up," Egan said, according to the Los Angeles Times.
"The whole thing about these great wines is that they're meant to be historical artefacts. Every time you open one, it's less of a dwindling supply," Egan said.
Mr Koch said Kurniawan was a "clever counterfeiter" who "made some stupid mistakes". "For example, he sold a rare French wine supposedly from 1928, which was six years before that particular wine was ever bottled," he said.
In his closing arguments, assistant US Attorney Joseph Facciponti said that Kurniawan's sales had become "the stuff of legends". "For a while, his magic show worked," Facciponti told the jury, the Associated Press reported.
Independent