Brine is water saturate or nearly saturated with salt (NaCl). It is used (now less popular than historically) to preserve vegetables, fish, and meat. Brine is also commonly used to age Halloumi and Feta cheeses. Although brine is used in preservation much like sugar or vinegar, it can be used to great effect in transportation. Brine is a common fluid used in the transport of heat from place to place. It is used because the addition of salt to water lowers the freezing temperature of the solution and the heat transport efficiency can be greatly enhanced for the comparatively low cost of the material. At a concentration of 23.3%, the freezing point of the solution is lowered to -21°C (252.15 K, -6°F).