The surprising science inside your favourite bag of crisps

The humble bag of potato chips, a ubiquitous snack, belies a surprising depth of scientific innovation and decades of dedicated research. Scientists have tirelessly worked to cultivate potato varieties capable of thriving in diverse climates, resisting pests and diseases, enduring months in storage, and consistently delivering that satisfying crunch consumers expect. This intricate process also adapts to evolving consumer preferences, such as the growing demand for smaller chipping potatoes driven by the shift towards snack-sized portions.

"The potato industry is dynamic," explained David Douches, a professor at Michigan State University who spearheads the institution’s Potato Breeding and Genetics Program. "The needs change, the costs, the pressures that they have, and the markets change. So we have to adapt to that with our varieties."

Over the past 15 years, Professor Douches has been instrumental in developing five new potato varieties specifically for chip production. His most recent breakthrough involves a bioengineered potato designed to maintain a proper sugar balance when stored at colder temperatures, a crucial advancement in preventing spoilage. Seeds for this innovative potato are currently undergoing commercial testing, with market availability anticipated in the future.

Beyond the snack aisle, Professor Douches’s work extends to combating global hunger, having developed disease-resistant varieties for farmers in Nigeria, Kenya, Rwanda, and Bangladesh. Domestically, his efforts bolster US chip manufacturers, satisfy snack enthusiasts, and support Michigan’s substantial £2.5 billion potato industry. While Idaho leads the nation in overall potato production, Michigan stands out as the foremost producer of potatoes destined for chips.

David Douches, a Michigan State University professor who leads the school's Potato Breeding and Genetics Program, holds a potato chip in his hand during a taste testing in East LansingAP Photo/Mike Householder

Currently, approximately 50 distinct potato varieties are cultivated for chip production across the US. This effort is coordinated by the National Chip Program, a collaborative initiative uniting Michigan State and 11 other university breeding programmes with growers, chip manufacturing companies, and the US Department of Agriculture.

The drive to enhance these varieties is relentless. Tim Rendall, director of production research at Potatoes USA, a trade group overseeing the chip programme, noted that the National Chip Program assesses around 225 new potato varieties annually, selecting 100 for further trials.

This close-knit partnership between researchers, farmers, and potato chip companies is a rarity within the food industry, according to Phil Gusmano, vice president of purchasing at Better Made Snack Foods, a Detroit-based chip producer since 1930. Gusmano highlighted Better Made’s close collaboration with Professor Douches during the development of two varieties the company now utilises.

"We were able talk about size profile and different needs that make a really good chip," Gusmano said. "And the great thing is, they’re willing to listen to what we have to say, because if they put together a potato that doesn’t really meet the needs for the end processor, it doesn’t do them any good."

Developing a new potato variety can be a lengthy process, often taking up to 15 years, Professor Douches revealed. The seemingly simple potato possesses a surprisingly complex genetic structure, featuring four chromosomes per cell compared to the two found in most species, including humans. This complexity makes it challenging to predict which traits will be inherited by cross-bred plants.

"We’re never able to fix a trait and carry that over to the next generation, so it’s very difficult to find a potato that has all the traits that we want," Professor Douches explained.

Better Made Snack Foods worker Tonya Tinsleydoes quality control checks on potatoes at a processing facility in DetroitAP Photo/Mike Householder

Professor Douches’s fascination with potato breeding and genetics began during his graduate studies. At Michigan State, his focus on chipping potatoes is a natural fit, given Michigan’s prominence in the sector. The Michigan Ag Council estimates that around 70 per cent of the state’s potato crop is earmarked for chip processing, with one in every four bags of potato chips produced in the US containing Michigan-grown potatoes.

One of the most significant challenges in Professor Douches’s 40-year career has been breeding potatoes that can be stored for nearly a year. Historically, harvested potatoes were stored in large piles at approximately 10 degrees Celsius. Colder temperatures cause sugar levels in the root vegetables to rise, leading to darker potato chips, while warmer conditions risk rot.

"You think they’re just these inanimate objects, but they actually are respiring and breathing," Professor Douches noted. "When you do that to them, you’ve got, like, a two- to three-day window where they’re happy."

His Manistee variety, introduced in 2013, can be safely stored until July at 7.2 degrees Celsius. The new bioengineered potato promises even greater longevity, capable of storage at 4.4 degrees Celsius.

Mr Gusmano confirmed that Better Made previously sourced potatoes from outside Michigan for half the year because local Michigan potatoes, harvested in the autumn, could only be stored until February. The company now uses newer varieties, such as Professor Douches’s Mackinaw potato, which can be stored until July and offers resistance to several common diseases.

"We’re not shipping potatoes from all over the country to be fried here in Michigan," Mr Gusmano said. "Instead, they’re being shipped from an hour and a half away all year long."