Brine is water that has more than 5% salt in it. It is used for preserving food. For this it is much like vinegar or sugar. Brine is also used to transport heat. Adding salt to water lowers the freezing point of the water. The solubility of salt in water depends on temperature. At 15.5 ° Celsius, a saturated solution of brine can hold 26.4 % salt by weight. At 0°, it can hold 23.3% salt.