Jar of wild berry jam
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Potassium sorbate is a common preservative. When you buy it from a store, it will likely be in a concentrated powdered form. To use it, you must first dilute it to a 25 percent solution, but since it is a preservative, the pre-mixed solution will keep without spoiling indefinably sealed in a jar in your pantry. After making the solution, you can use it in your cooking to increase the shelf life of foods.

Fill the jar with 3 cups warm water. Measure 1 level cup potassium sorbate and pour it into the water.

Mix the water and potassium sorbate thoroughly with the spoon until all the powder has been dissolved. Seal the jar and store indefinitely in a cool, dark place. This is your 25 percent potassium sorbate solution that you will use to preserve foods.

Add 1 tsp. of the potassium sorbate concentrate mix made in Step 2 to each 1 qt. of food you want to extend the shelf life of before you can or bake it. Follow proper canning or jarring procedures (see link in Resources).