Combine brown sugar, karo syrup, molasses, butter, salt, and white vinegar in a heavy saucepan.
Boil the mixture until a small sampling becomes brittle when place in cold water.
Add the baking soda and stir, the mixture will be foamy.
In a large mixing bowl, pour the mixture over the popped popcorn and mix.
Cover a cookie sheet in wax or parchment paper and pour the popcorn over it. Let it cool and store in an air-tight container. Enjoy.
Check out a similar Caramel Popcorn recipe video from Kitchen Divas.