The best camping percolator or even a mediocre backpacking coffee press would comprise of materials that prevent heat from seeping out. Not only that but even the holding-area of the mug machine should not become too hot, thus heat-resistant materials must be used. Stainless steel would also be a wise choice. Look for nylon top so that your coffee remains hot. Over and above all, all materials used to construct your coffee maker must be resistant to melting.