To extract pectin from apples, follow this simple process: 1  Cut 2 pounds of tart green apples, with the skin, into pieces. 2  Add pieces to 4 cups of water and 1 tablespoon of lemon juice. 3  Let apples boil for 30 minutes, until the volume reduces in half.  Strain apples through a 1  cheesecloth. Boil apples for another 20 minutes.