More than love went into that box of chocolates you got for or from your sweetheart on Valentine’s Day. There’s also a considerable amount of engineering.

From product development and testing, to packaging and distribution, engineers have a hand in making chocolate. Although the cacao tree was exclusively cultivated in the Americas for thousands of years, it wasn’t until relatively recent times that engineering and technology have transformed its fruit into the chocolate that we now know and love.

According to Craig F. Moyer, a chemical engineer and manager of process engineering at Hershey Chocolate NA, a division of Hershey Foods, the Europeans first discovered chocolate upon Columbus’ return from his fourth voyage to the Americas. In the next hundred years, Spanish royalty consumed the prized cacao as a beverage and kept its existence secret until 1606.

Even then, chocolate remained a beverage for Europe’s wealthy until the 19th century and the advent of the steam engine. It wasn’t until 1828, when C.J. van Houton invented a cocoa press in Holland, that chocolate began to take its present shape.

By mid- century, Cadbury had successfully recombined cocoa butter with a chocolate liquor and sugar blend and the first bar chocolate was introduced commercially in England. In 1876, the Swiss perfected a process that mixed milk with chocolate liquor, dried out the moisture, replaced it with cocoa butter, creating the European milk chocolate industry.

In the nearly 120 years since, engineers have continued to refine chocolate production. Moyer says that, “The technological explosion of the latter half of 20th century, and specifically that of the last 20 years, has not been lost on chocolate manufacturing.” A member of the American Institute of Chemical Engineers’ (AIChE) Speakers’ Bureau, Moyer is one of the many chemical engineers – from entry level to chairman of the board – that Hershey has employed over the last 50 years to refine its chocolate-making.

Ralph Lee, a chemical engineer with M&M/Mars, says that caramel production is typical of engineering know-how. Caramel is produced by combining fats, sugars, and milk and cooking the mixture. But it is much more complex than that. He notes: “The development of color and flavor in caramel is the result of a complex series of reactions known as the Maillard Reaction.

Variables such as kettle size, moisture level, residence time, pressure, and temperature all can significantly affect the consistency, and quality, of the mixture.” Cooling of chocolate also poses significant challenges. “Chocolate must be cooled very carefully to maintain the high gloss and creaminess of a quality chocolate. A temperature change of as little as just 1 degree Celsius at the wrong time can result in chocolate with a gray surface and gritty texture,” says Lee. Fortunately, he added, the critical variables can be controlled by careful engineering of the process.

What’s next? How about a chocolate that may turn out to be less expensive to manufacture and less fattening. Greg Ziegler, an associate professor of food science at The Pennsylvania State University, and Brian Fischer, a recent Penn State graduate, said that such a chocolate may not be far off.

“Semi-sweet chocolate,” Ziegler noted, “is basically a concentrated suspension of cocoa and sucrose particles dispersed in a continuous fat phase. The primary component of this fat is cocoa butter, which also happens to be the most expensive ingredient. The key is to minimize the fat content while still retaining chocolate’s unique physical properties and flavor.”

By designing the particle size distribution and optimizing the flow properties of the chocolate, the engineers believe that they have developed a lower-fat chocolate that is still able to be manipulated into the final product, whether it’s molded, coated, layered, or formed into chips. As a result of their research, Ziegler is confident that a new age in chocolate production will soon be upon us. He concluded, “Cocoa butter content can be reduced while maintaining nearly identical flow properties, resulting in a cost savings to manufacturers, and perhaps more importantly, reducing the caloric content.”