Prepare 2 baking sheets by lining each with wax paper.
In an air popper machine, pop the popcorn kernels. Sift through and remove any unpopped kernels. Place popcorn in a very large bowl (or use two bowls or a cleaned empty sink).
In a large pot (5 quart), combine sugar, corn syrup, water, butter, and salt. Bring to a boil over medium-high heat and add 4-6 drops of food coloring (however much you desire). Continue to boil for about 4-5 minutes until bubbles begin to become larger and fewer. It will still be thin. Or if you have a candy thermometer cook until 245 degrees and then remove from heat and stir in vanilla.
Pour over popcorn and then mix with a rubber spatula until all the popcorn is evenly covered.
Rub about a teaspoon of softened butter all over your hands and form 26-30 baseball sized balls (apply more butter if popcorn starts sticking to your hands). Pack gently/loosely so they aren't so hard when you bite into them. Set balls on prepared pans and allow to cool/dry completely.
Once cooled, place each popcorn ball in a sandwich size ziploc bag.