Thomas Duroux held his breath as he removed the cork from a bottle of Chateau Palmer 1961. Reaching down the bottleneck with a special strainer, he extracted any remaining pieces of cork in the wine.
Mr Duroux is among a delegation of Chateau Palmer executives who are undertaking a meticulous three-day operation to recork about 480 bottles of the sought-after Bordeaux vintage at the Lisboa in Macau.
Collected by Macau casino mogul Stanley Ho Hung-sun and his nephew Alan Ho Yau-lun, the bottles - with a retail value of more than $8 million - comprise the world's largest private collection of the 44-year-old wine.
'It is a kind of customer service after 42 years' in the bottle, said Mr Duroux, general manager of Chateau Palmer, as he took a sip of the wine to ensure its quality then spat it into another glass.
'We do it for free. This is really an incredible chance for us to know there is still some of this wine available.'
Chateau Palmer's technical director Philippe Delfaut, who carefully began the next stage of the recorking process, said the corking machine was an adaptation of a 50-year-old device, with a modern fitting that added a small amount of carbon dioxide gas to prevent oxidation.
The manually operated corking machine - the same one used to bottle the wine in 1963 - and an electrical capping device were flown in on Monday from the chateau in Bordeaux, France.
The recorking is being carried out in a private dining room at the Lisboa's Chinese restaurant, Portas do Sol. The 400-sq-ft room is being kept at 16 degrees Celsius during the process.
After half the collection had been dealt with, Mr Delfaut said only four bottles had been judged not good enough for recorking.
Once the wine is checked, a new cork, marked 'rebouche en 2005' (recorked in 2005), is inserted to seal the bottleneck.
The collection, mostly shipped from Bordeaux to London then Macau in the mid-1990s, is kept in the Lisboa's wine cellars.
Alan Ho said the wine - which well-heeled customers can order for $18,000 a bottle - was a small portion of the thousands of prestige wines at the Lisboa.
Mr Ho's passion for collecting continues - he receives dozens of e-mails and brochures a day from wine sellers. 'We can always convert more rooms into cellars' if space ran out, he said.