Aluminum beer bottles recently have been introduced as an alternative to traditional glass bottles or aluminum cans. Advertisements claim that the new aluminum bottles keep beer "colder longer" than glass bottles. Because the thermal conductivity of aluminum is over 150 times that of typical soda-lime glass, and because the bottle wall is thinner this claim appears counterintuitive. In this investigation, the thermal performance of commercially available aluminum and glass beer bottles was examined using experimental, analytical, and computational methods. It was found that when exposed to ambient air glass and aluminum bottles perform in. a nearly identical manner with respect to keeping their contents cold. Each bottle showed an approximately 15 degrees C temperature rise over a 2.7-hour period. Heat transfer is controlled by natural convection and thermal radiation at the outer bottle surface; hence, the difference in thermal conductivity between the bottles has no significant impact on the temperature transient. Computational simulations also predict that when an aluminum bottle is immersed in an ice-water bath, the liquid cools more quickly than in glass due to the lower thermal resistance of the aluminum versus the glass; when held in the hand, the glass bottle allows the liquid to warm more slowly than the aluminum bottle.