A container assembly heats or cools a product inside an inner container. An outer jacket at least partially surrounds the inner container, with a first internal volume and a second internal volume in the space between the outer jacket and the inner container. A first temperature-change reagent is contained inside the first internal volume, and a second temperature-change reagent is held in the second internal volume, with a reagent separator between the two. Several penetrators are disposed to penetrate the reagent separator to produce openings through the separator and through which the two reagents can mix. Steel wool inside the first internal volume acts as a steam condenser. The outer jacket includes a jacket top ring secured around an upper surface of a standard can, a jacket body secured to the jacket top, and a flexible jacket bottom that carries several spikes molded onto the jacket bottom.