mixed kool aid does expire ,because the water can develop mildew just like any other beverage and the sugar is a perfect breeding ground for bacteria .Drinking open beverages more than 2 weeks old is not a good idea in general Happy To Help! read more
KOOL-AID drink mix contains a "Best When Used By" date which refers to the date recommended that you use the product by for best physical and/or sensory quality. read more