Plenty of nice cool beer in the icebox.
But, as soon as you take it out, it starts warming up.
So, think out of the (ice)box.
We need an icebox extension. A 3D printed icebox extension!
It actively cools a bottle, tin or glass of beer outside the box.
A small Peltier element (4x4 cm) is used, which is a low cost heat pump. It transports heat from one side to the other. As soon as electric current flows through the Peltier element, one heat sink heats up, while the other cools down. Peltier elements and heat sinks are common products in hobby electronics shops. At the hot side you really need a large heatsink, otherwise the cold side will heat up as wel. If the hot heatsink is large enough and the fan powerfull, no additional electronics are needed:
http://www.aliexpress.com/snapshot/6324491655.html
supplies complete units with fan and heatsinks for about $18,-
Maybe the printed parts need some modification to fit the sizes (see photo of white box).
This printed gadget has a triple function.
The double wall (infill about 30%) serves as a thermal insulator.
It houses the Peltier element with the two heat sinks (cold one on top).
It holds a fan at the bottom to cool the lower heat sink.