Warring States wine made more than 2,300 years ago, as deep as the sea

The copper flat kettle contained light green wine when it was unearthed, making it the earliest physical wine discovered.
The tightly sealed pot of fine wine lost a lot of alcohol, and now only half the pot remains. The color of the wine has turned dark green.
Later, it was tested that these two wines did not contain alcoholic acid salts. They should not be fruit wines but non-distilled wines made from grain.
Wine contains more than just alcohol. It has seventeen other ingredients, like fat, sugar, and metal ions, such as copper, lead, tin, and silver. These metal components should be the main reason the wine is dark green.