Christie's used to hold its wine auctions in Chicago, and while I lived there, I was invited to a pre-sale tasting w/ lots of wines from the 1800's. The oldest red was an 1847 Gruaud, the oldest white an 1893 Y'quem Unhappily, with various moves, a divorce, kids, etc. I've lost my tasting notes so cannot provide the exact vintages. I remember that most of the wines from the 19th century, including the Y'quem, where thin, acidic and uninteresting. It could be the was because the wines were poorly stored at some point in their lives, or it could be intrinsic to the wines themselves. I suspect it was poor storage, because one of the wines we tasted was the 1870 Latour, and it was dead. But Broadbent and everyone who has tasted well-stored bottles proclaims it a marvel.
The star of the tasting was the 1899 Suiduiraut. It went for very little money (only a few $100/bottle) but as a poor academic, I couldn't afford it. Sure wish I'd bought all the bottles, as they were glorious.