Prepare a 9-inch square pan by lining it with parchment paper.
In heavy 2 to 3-quart saucepan, melt butter over medium heat. Stir in sugar, corn syrup, salt, sweetened condensed milk and apple juice concentrate. Cook over medium heat stirring frequently to prevent scorching until the temperature of the mixture reaches 248°F (firm ball stage). Remove from heat.
Pour mixture into the prepared pan. Allow to completely cool.
Turn candy out of pan and cut into ¾-inch pieces. Wrap each piece in 2¾-3-inch squares of nonstick aluminum foil or waxed paper. Store in airtight container.