If salt is added to lemonade instead of sugar, then the lifetime
of the lemonade is vastly increased. That is, it lasts a lot longer
than it normally would.
The effect has nothing to do with the intrinsic (internal) properties
of the lemonade, such as physical or chemical properties.
The effect is rather an external, mainly socio-cultural one.
With salt dissolved in it, in an amount roughly equal to the
otherwise typical amount of sugar, anyone at the party who tastes
the lemonade encounters the series of physiological reactions
described in medical terms as the "Trans-Mongolian bleah, yuk, feh,
waugch, hoo boy" syndrome. That particular individual stays as far
away from the pitcher as possible for the rest of the evening, and
may even communicate a vivid description of his experience to
others, whether explicitly or implicitly. A general sense of repulsion
thus propagates throughout the group, and the rate of change of
the quantity remaining in the pitcher decays to virtually zero, vastly
extending the life of that batch of the beverage.