Preserving finos

[Thomas]

Scoop, in my experience the Vacu Van doesn't work well on table wines so I cannot imagine it could do anything for fino sherry.

Nitrogen is the best solution. You can buy small nitrogen dispensers (Mead's Wine Trader might have them listed).

Perhaps, putting the unused portion of sherry into a smaller vessel (375ml) will buy some time, but not much, since the transfer from one bottle to another introduces oxygen.