A young Chinese man paid the astronomical sum for a two-centilitre measure of 1878 Macallan whisky in the renowned Devil's Place whisky bar at the Waldhaus Hotel am See in St Moritz.
Until it was opened especially for the paying guest, the bottle was thought to be the only remaining unopened bottle of the vintage, and had been valued at 50,000 francs.
But on Friday the whiskyexpertes.net site claimed the bottle was a fake – although it pointed out that the hotel probably didn't know that and sold the measure in good faith.
Speaking to newspaper 20 Minuten, Sandro Bernasconi, the manager of the Waldhaus, said he had noted the allegations and would now try to establish if they were true.
The bottle was purchased by his father 25 years ago for a five-digit amount, and the hotel never suspected that it was a fake, he said.
Now the bottle is opened, its contents can be tested, and Bernasconi said he was in contact with a renowned whisky tester in Scotland, though the process could take some time.
If it is proved to be fake, the hotel intends to refund the money paid by the Chinese guest.
“I already spoke to the guest from China. He also heard of the forgery rumours but he did not blame us since the bottle had been unopened and the authenticity could not be checked,” said Bernasconi.
He added that the hotel would take legal action against the seller if the bottle is proved to be fake.
“I am not afraid of the result. I want to know the truth,” he said.
The hotel's Devil's Place bar serves 2,500 different kinds of whisky, putting it in the Guinness Book of World Records.
The second most expensive whisky on the menu is a 1940 Macallan costing 451 francs a glass, Bernasconi told the paper.