On Food and Cooking

on the tongue, general health, age, and
experience. Most young adults can identify as
salty a water solution with 0.05% salt, or 1
teaspoon in 10 quarts/liters, while people
older than sixty years generally detect
saltiness only at double that concentration.
Many manufactured soups, which many
people experience as moderately to very salty,
are around 1% salt (10 grams, or 2 teaspoons
per quart/liter), approximately the same
concentration as our blood plasma. Some may
be 3% salt, which is the average salinity of
seawater.
It appears that the basic liking for saltiness is
innate in humans, no doubt because salt is an
essential nutrient. The preference for a certain
level of saltiness is learned through repeated
eating experiences and the expectations they
create in us. Preferences can be changed by
constant exposure to different salt levels,
which changes expectations. But this takes
time, usually two to four months.