If the coating on your pink popcorn doesn't dry, it could be due to one of two things: 1. Not reaching the correct temperature when boiling the syrup coating. It's crucial for candy-making to reach the temperatures listed in recipes. If temperatures are not reached, candies (including the coating in this recipe) may not harden properly which could result in a sticky coating. Make sure you use a candy thermometer to make your coating. 2. The weather/humidity. If you live in a very humid climate, or make this on a particularly humid day, the popcorn may not harden. In this case, you could try putting it in a very low-temperature oven, making sure to check it often.