In the sherry towns a pale wine sits in a barrel that is not filled to the top. A film of yeast — flor — grows on the surface and keeps air off the liquid. That is biological ageing. It gives you fino in Jerez and El Puerto, and manzanilla if the same work happens in Sanlucar de Barrameda, next to the river mouth. Manzanilla is a legal name tied to that town, not a grape.
If the flor dies and air reaches the wine, you get amontillado: first biological, then oxidative, amber and nutty. Oloroso never really lives under flor; it ages in contact with air from the start, darker and broader. Palo cortado sits between those two. Sweet bottles are usually Pedro Ximenez or moscatel, from grapes dried in the sun, or a dry wine blended with that syrup. Cream is a blended sweet style, not a separate vineyard.





