Microgravity has some obvious problems. The problem is that the food floats. Salt and pepper is a good example. NASA uses them in liquid form because the dried grains float out of shakers and clog vents, equipment, and astronauts’ eyes. According to the Kennedy Space Center, astronauts should use tortillas because they can’t eat bread in space because the crumbs will float. The reason liquids such as beverages and salt and pepper solutions work fine is that they are bound to the package by surface tension.
Other problems caused by microgravity are less obvious. According to the University of Colorado, one of the biggest challenges in preparing meals for astronauts is the inability to have refrigerators in space. The back side of the refrigerator is hot, and the hot air does not rise in microgravity. The heat emitted by the refrigerator he collects in one place, creating a very hot environment where equipment can overheat and fail. Because perishable foods cannot be left at room temperature for more than a few hours, NASA says most foods must be freeze-dried or dehydrated.
Even stranger is the effect of microgravity on taste. The Kennedy Space Center explains that astronauts are constantly congested because their sinuses cannot drain without gravity. As a result, astronauts have a diminished sense of smell, food tastes bland, and heavy seasonings are required. However, the reduction in tasting power would have been a blessing in the early days of space dining.