Am I supposed to drink the gunk at the bottom of a wine bottle? How do I do so gracefully at a dinner party if I've landed the end of the bottle?
Supposed to? Not exactly, though it will do you no harm.
Good-quality wines, which tend to receive little if any filtering, will throw a natural deposit over time. The sediment is best left in the bottle because it does nothing for flavour and may in fact impede your enjoyment with all that dry grittiness. Should too much sediment end up in your glass, let it rest for a few minutes and sip until the solids get in the way. If it's an expensive cuvée, you might want to take the trouble of decanting the wine into another glass through a fine sieve or coffee filter to rescue as much liquid as possible.
When serving an old bottle from the cellar, stand it upright for at least eight hours to enable the sediment to settle at the bottom. Then slowly pour the bottle into a decanter or a glass, being careful to stop when the sediment reaches the bottle neck. It helps if you do this against a brightly lit background. No host should be pouring the last dregs into a guest's glass. Wine is meant for sipping, not eating.