According to multiple sources, including Food Network, CandyStore.com, Reddit, Candy Club, and Candy Funhouse, the most sour candy is Toxic Waste Hazardously Sour. It is a small, hard candy that delivers an incredibly potent and long-lasting sour experience. Other sour candies that are also considered very sour include Barnetts Mega Sour Fizz Bombs, Warheads, Sour Skittles, Cry Baby Tears Extra Sour Candy, and Sour Patch Kids Extreme.