Manipulating the Sherry Flor into Good Wine

As the wine grows older in cask, in the dry atmosphere of the sherry towns, it gradually evaporates, but it loses water more rapidly than alcohol, and if it is not refreshed with younger wine, it gets steadily stronger and its flavor increases. At the same time, the flor gets thinner and darker, until it eventually sinks to the bottom and disappears altogether when the wine gets too strong. In the scales of a solera, where the old wine is drawn off at regular intervals and replaced with younger wine, it is possible to continue breeding flor indefinitely.

When a butt had been in position in a solera for fifty or sixty years, there was a considerable accumulation of dead cells in the lees. The sherry flor is a deadly enemy of the mycoderma aceti, or vinegar flor, and if any particles of vinegar flor fall into a butt of sherry, the two yeasts fight for existence and the stronger wins. If the sherry is breeding healthy flor, the mycoderma aceti does not stand a chance. A few butts of must turned into vinegar every year, but once the flor is really established, the wine is absolutely safe.

In fact, in a well-managed bodega, the number of casks going the wrong way was so few that one or two were turned into vinegar on purpose, to make sure there was enough for the summer salads and the local gazpacho. Neither the good nor the bad yeasts can live without oxygen, and it is largely for this reason that growers in districts where wines were liable to be attacked kept their casks tight-bunged, though this was never necessary in the sherry towns.

The sherry flor is a deadly enemy of the mycoderma aceti, or vinegar flor, and if any particles of vinegar flor fall into a butt of weak sherry, the two yeasts fight for existence and the stronger wins.