Since the early days of space travel, a consistent complaint has been bad coffee. Now a group of freshman engineering students at Rice University has developed a simple approach to alleviating this problem.

Hot coffee has been a part of space travel since the beginning of the Apollo program, which included a source of hot water for reconstituting food and drink. There are now many versions available, all freeze-dried and reconstituted using hot water at 70 degrees Celsius (158 degrees Fahrenheit).

Astronauts can choose from ordinary coffee (leaded or unleaded) and Kona coffee. It comes black, with artificial sweetener, with cream(er), with both, with sugar, or with cream(er) and sugar. And it all tastes bad.

"The key to freeze-dried food is Tabasco sauce."

The above quote is from a hiker and hunter, but is apropos here. Although modern freeze drying methods have greatly improved the taste of freeze-dried food and drink, even on Earth such foodstuffs are widely regarded as providing only a limited imitation of the taste experience that goes with ingesting "real" food and drink. Freeze-drying can cause the loss of some of the more volatile aroma compounds, thereby altering the taste. In addition, changes in texture during the freeze-drying process can alter the experience of eating a particular food. Tabasco sauce and similar condiments and additives can kick the flavor up a notch.

An additional factor in our appreciation of food and drink is related to the well-known psychological phenomenon of the Uncanny Valley. The Uncanny Valley is a concept used to explain why humanoid robots are so difficult to accept. If a robot is only vaguely humanoid, we take it for what it is. However, if it is close enough to appearing human, we concentrate on every aspect that makes it appear non-human, with the usual result being a "creepy" feeling.

A similar phenomenon takes place in food and drink. A processed food with a dramatically altered gustatory experience can be evaluated on its own merits. However, a processed food that is nearly correct will be perceived in terms of its difference from the ideal. In this case, the food will generally be perceived as "off" or on the verge of being spoiled. Sometimes food that is a bad imitation of some ideal food will be preferred to a fair to good imitation.

Culinary challenges in space

Do food and drink taste the same when you're in a small weightless capsule in orbit? In a word, no. The reaction of our taste buds is limited to five sensory responses (bitter, salty, sour, sweet and umami), but the experience of eating or drinking is strongly affected by a number of other sensory modes. These would include smell, texture, temperature, and chemesthesis (through which we gain the sensation of piquant flavors from chili peppers, black pepper, ginger, and horseradish). Of these, the sense of smell has perhaps the strongest influence on the experience of eating and drinking, and is particularly known to evoke old memories of events associated with similar odors.

The effect of weightlessness on the taste experience results from at least two physical effects. When sampling food on Earth, the aroma molecules from warm food are carried quickly into the nasal cavity by thermally-driven convection and turbulent flow. The main mechanism is that hot gas rises, and cool gas falls – a process driven by gravity. However, in weightlessness thermally-driven motion of gases is much slower than on the ground. In the absence of the odors of food, the experience of the taste of food is greatly suppressed.

The second effect of weightlessness is that fluids within the body are not pulled into the lower body by gravity. As a result, fluids accumulate in the astronauts' upper body, so that they chronically suffer severely stuffy noses. We are all acquainted with how bland food tastes during the course of a cold, but for astronauts the cold doesn't go away.

Space coffee

"Moderation in all things" is a general guideline for life that apparently originated with the Ancient Greek philosopher Aristotle. When it comes to coffee, NASA may have gone missing that day in school. Black coffee is difficult to ruin, although the freeze-drying process does change the taste. However, there is a particular problem with premixed NASA coffee with additives. If you want sugar and/or creamer in your premixed NASA coffee, the result is a cuppa rendered syrupy with huge amounts of these additives. Astronauts complain more about the artificially large viscosity than about the taste, but both receive failing grades.

Rice University students, from left, Robert Johnson, Benjamin Young and Colin Shaw show their coffee as you like it for astronauts aboard the International Space Station

Among the goals of the Texas Space Grant Consortium (TSGC) is to provide opportunities for undergraduate students to participate in space based research and exploration. One mechanism for implementing this goal is the TSGC Design Challenge. Designing a “coffee the way you like it” system for the use of astronauts on the International Space Station was one of the 2013 Challenges taken up by a trio of Rice University engineering students (Robert Johnson, Colin Shaw and Benjamin Young) and their faculty sponsors, Drs. Ann Saterbak and Matthew Wettergreen of Rice's Bioengineering department.

The challenge was to develop a method and equipment that allows astronauts to add liquid ingredients (cream, sweetener, and lemon juice) from a foil package to another that contains black coffee or tea. No spills in microgravity can be allowed, as these have a tendency to migrate into equipment and cause faults.

The Rice freshmen designed their system around the existing black coffee pouches. NASA supplied them two-ply heat sealed pouches to hold the sugar syrup and cream. The beverage and condiment pouches all have a septum which allows access to their contents without allowing any of the liquid contents to escape.

How is the new system used to make coffee with sugar? In use (see the video below), hot water is injected from a pistol-like dispenser through a septum into a coffee pouch and a sugar pouch. After dissolving the contents, a roller mechanism similar to those used to dispense all the toothpaste out of a toothpaste tube is engaged on the sugar pouch. The rollers were made on a 3-D printer.

To prepare coffee with sugar, a pouch to pouch drinking tube is inserted into the coffee and sugar pouches through their respective septums. A few cranks on the roller, and the coffee has just the right amount of sugar. The drinking tube is clamped shut, the contents of the coffee pouch are mixed by squeezing the pouch repeatedly, and then the drinking tube is unclamped so the astronaut can drink the coffee made to order. The spare sugar and creamer can be stored for later use.

Source: Rice University