Water is a liquid AT NORMAL TEMPERATURE AND PRESSURE. Reducing the pressure
of a fluid containing water will have a similar effect to raising the
temperature.  There is every chance that the water content will reduce as Jan
describes.
Before we all start experimenting with honey buckets, sticky tape and vacuum
cleaners, consider that water is not the only fluid in the bucket that will
be affected by the reduction in pressure.  You are likely to lose the most
precious, the most volatile, the most ephemeral of essences: the subtle
differences in bouquet and flavour that distinguish a fine wine from plonk.
You will be selling your customers the residue.  It may still be pretty good
but it won't be the best.
Chris Slade