Brine is basically salt water that is used for curing, cleaning, and aging cheeses of all varieties.  The final salt content in aged cheeses is very low as it precipitates out over time, but certain cheeses maintain a very high salt content, like Feta Cheese.   

When storing brined cheese at home in the refrigerator, you can make your cheese last longer by refreshing the brine that your cheeses are stored in. If brine becomes cloudy it doesn’t mean that it is bad, it is likely just dairy solids that are breaking down from the cheese and causing this. If you develop a mold in your brine, just boil it and filter it through cheesecloth and it can be reused. Most cheese makers believe that repurposed brine solutions add individual flavors to each new batch of cheese. Brine may need to be refreshed by having salt added to it over time as the cheese will absorb salt from the solution decreasing the percentage of salt to water over time.

For long term storage of brined cheese, a 5-8% solution works very well. We use 8% at La Verde Oveja for aging our Feta cheese.