No, not food coloring. BIG LEPRECHAUN ENERGY. Burly barkeeps squeeze shamrock energy out of leprechauns' little red beards. Don't worry, it doesn't hurt! It tickles! They laugh until they cry whiskey and drool guinness! Thank you, little weird fairies, for helping mankind get belligerently drunk every year. These sunnies harness the same energetic forces, minus the leprechaun juices.