The biggest test for Australia's most famous wine brand

Penfolds is the most famous Australian wine brand and has been on a rollercoaster ride for the past four decades, having been through six different corporate owners.

It resides now as the crown jewel in ASX-listed Treasury Wine Estates, which had delivered immense riches to shareholders on paper after soaring to beyond $19 late last year on a China luxury wine sales boom. But it is now less than half of that, hovering around $9.18, because of the fear that the hardline approach from China's President Xi Jinping and senior leaders in the Communist Party could either block Australian wines from being sold into China, or impose punitive tariffs in a worsening trade spat.