The astronaut can choose hot or cold water to rehydrate each food item. A blue push button has to be pressed to select cold water. Both buttons are illuminated when energized. After the selected volume of water is dispensed, the push button will begin to flash on and off. After water is dispensed inside the container, a waiting period has to pass before the food can be consumed.
Many astronauts kneed the container to distribute the water more evenly throughout the container.
The wating period also can be used to heat the food item in the galley's oven. A switch turns on and off three oven fans. These fans circulate warm air over a heat sink, thus providing forced convection heating for the rigid packages. The flexible packages are held against the heat sink by three spingloaded plates, and are warmed by conduction. The oven has a heating range of 160 to 185 degrees Fahrenheit.