Mary writes:
Flor is the benevolent, film-forming yeast that makes sherry the unique wine that it is.
Flor floats on the top of the wine and prevents oxidation. And as in other parts of the world, the particular yeast cells that make up Flor are particular to the area where sherry is made.
Flor yeast has the capacity to perform a second metabolic action after fermentation. It uses the alcohol and oxygen from the air to produce a coating which floats on the surface of the wine — before bottling so you’ll never have to drink it. But you will be able to smell it in all Fino and Manzanilla sherry.