Grandjo Royal Demi-Sec White is a White wine. See reviews and pricing for this wine.
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Whether it has been properly stored will affect its desirability. The bottling year, will also influence the value. I think you need to consult a wine expert to see if it's worth putting to a specialist auction.
Remember wine doesn’t always get better with age. Heat can have an adverse effect on it. Definitely get the opinion of a wine auction expert. It could be quite collectible. What’s the story behind it, if you can say?