John N. Lundström, a native of Sweden and the director of the Monell Chemical Senses Center, has always been captivated by the world of scents. However, it was his German Shepherd, Ella, that truly set him on the path to studying olfaction. During their walks, Lundström noticed that Ella could always detect the urine of other dogs, while he remained oblivious. Intrigued by Ella's varied reactions—sometimes wagging her tail, other times appearing anxious or even amorous—Lundström became fascinated by the concept of pheromones, chemical signals that many organisms emit to communicate. This curiosity eventually led him to earn a Ph.D. in psychology and lead a team at Monell, where he studies the science of human scent and its impact on behavior.
The Infamous Swedish Surströmming: A Fermented Delicacy
As a Swede and an expert in olfaction, Lundström has encountered some of the world's most pungent smells. Yet, nothing compares to the notorious Swedish fermented herring, known as surströmming. "It’s the most revolting, putrid, and nauseating delicacy I’ve ever encountered," Lundström admits. "And I’ve been in the field of smell research for over a decade."
Fermentation or Decay? The Science Behind Surströmming
Historically, Swedes used salt to preserve food, including fish, a staple of their diet. However, during times of abundant herring catches and scarce salt supplies, they devised an alternative preservation method: fermenting the fish in barrels with just enough salt to control—but not entirely prevent—microbial growth. This process creates an anaerobic environment, leading to fermentation. While most cultures avoid anaerobic fermentation due to its association with spoilage, Swedes have embraced it, even as the resulting gases cause the cans to bulge—a clear warning sign of the potent contents.
Legal Restrictions: Why Surströmming is Banned Indoors and on Flights
Given its overpowering stench, Swedish law prohibits opening surströmming cans indoors, as the odor can linger for days. Some international airlines have even banned the cans from flights. To minimize the smell, experts recommend opening the cans underwater, allowing the gases to dissolve rather than permeate the air. This method also prevents the fermented contents from splattering on nearby individuals.
The Paradox of Smell vs. Taste: Why Surströmming Tastes Better Than It Smells
Despite its repulsive odor, surströmming is said to be surprisingly palatable. Lundström describes the experience as a stark contrast between smell and taste. "When you put it in your mouth, it’s a completely different story," he explains. The fermented herring is traditionally served with crisp bread, fresh onions, and boiled potatoes, creating a harmonious blend of flavors. The complexity of retronasal and orthonasal olfaction—the way scents are perceived through the nose and mouth—remains a mystery, even to experts.
The Role of the Brain in Processing Smell and Taste
Linda Bartoshuk, a researcher at the University of Florida’s Center for Smell and Taste, is equally intrigued by the interplay between smell and taste. She recounts the case of a patient who lost her sense of taste after a freak accident involving a can lid. Despite being unable to taste, the patient could still smell her favorite dishes, such as her mother-in-law’s lasagna. However, when she ate the lasagna, it tasted bland. Bartoshuk’s experiments revealed that the brain relies on cues from both the nose and mouth to process flavor. Without these cues, the brain struggles to interpret the sensory information correctly.
The Underappreciated Role of Oral Smell
While most people underestimate the role of oral smell, scientists are increasingly focusing on this area. The way we perceive flavor is a complex interplay of taste, smell, and texture, with the brain integrating signals from multiple sensory pathways. As research in this field continues, we may uncover new insights into how our senses shape our culinary experiences.
A Journey Through the Senses
From the curious reactions of a German Shepherd to the polarizing flavors of fermented herring, the study of smell offers a fascinating glimpse into the complexities of human and animal behavior. As researchers like Lundström and Bartoshuk continue to explore the science of olfaction, we gain a deeper understanding of how our senses influence our perceptions, preferences, and even our cultural traditions. Whether it’s the allure of pheromones or the acquired taste of surströmming, the world of smell is as diverse as it is intriguing.
