St. Patrick's Day Popcorn

I found this recipe on www.tasteofhome.com
Ingredients:
4 quarts popped popcorn
1 cup sugar
1/2 cup packed brown sugar
1/2 cup water
1/2 cup light corn syrup
1 teaspoon white vinegar
1/4 teaspoon salt
1/2 cup butter
8 to 10 drops green food coloring
Directions: Place popcorn in a large roasting pan; keep warm in a 250° oven. Meanwhile, in a large heavy saucepan, combine the sugars, water, corn syrup, vinegar and salt. Cook and stir over medium heat until mixture comes to a boil. Cook, stirring occasionally, until a candy thermometer reads 250° (hard-ball stage). Remove from the heat; stir in butter until melted. Stir in food coloring. Drizzle over warm popcorn and toss to coat. Cool. Break into pieces. Store in an airtight container. Yield: 6 quarts.