UNIVERSITY PARK, Pa. — Sour candies like Warheads and Sour Patch Kids have been popular for decades, so it shouldn’t be all that surprising that many children who grew up indulging in sour treats continue to enjoy similar tastes as adults. Scientists at Penn State have found that one in eight adults still like intensely sour sensations. All in all, this project sheds light on an interesting group of “sour likers” among us who enjoy exceptionally sour foods.
“This is the first time it’s been convincingly shown that there is a segment of adults who likes strongly sour things,” says John Hayes, a professor of food science and director of the Sensory Evaluation Center at Penn State, in a media release.
Earlier studies have shown that some children (roughly one in three) enjoy intensely sour tastes, Prof. Hayes explains, but this hadn’t been tested directly in adults. His recent study, conducted in partnership with researchers in Italy and published in the journal Food Quality and Preference, is the first to show that sourness enjoyment lasts well into adulthood for a sizable number of the population.
“Think about candies like Warheads and Sour Patch Kids,” Prof. Hayes explains. “The market tells us that there must be some people who enjoy them into adulthood, but now we have an estimate of how many.”
Initially, the international team set out to confirm the widespread belief that adults are generally averse to sourness, which they predicted would result in a drop in liking as sourness increases. To that end, they tested the liking patterns of sourness in two different countries across two different collections of individuals belonging to different food cultures: Italy and the United States.
The study authors measured the responses of 143 American adults to various levels of citric acid in water. Then, they measured responses among 350 Italian adults to pear juice spiked with various amounts of citric acid. Participants all had a similar age, gender, and ethnicity (mostly White) and came from a metropolitan area in Tuscany, Italy, and from the municipality surrounding Penn State.
Everyone had to rate the intensity and how much they liked a range of samples with varying sourness levels. Among both cohorts, researchers found evidence of three distinct patterns of response: a strong negative group in which liking dropped with increased sourness, an intermediate group showing a more muted drop in liking with more sourness, and a strong positive group where liking increased with increased sourness.
“Most people didn’t like sourness, so if you just average across the entire group, then you’d conclude that more sour equals bad,” Prof. Hayes explains. “But if you dig deeper, you find huge differences across people.”
By measuring liking levels, researchers were successfully able to test the hypothesis that “sour likers” may just be less sensitive to sour foods. This theory states higher concentrations of sourness for “sour likers” registered the same as lower concentrations of sourness in someone else.
“You could imagine a case where they’re just less responsive to sourness in general,” Prof. Hayes says. “But that’s not what we find. We find the people that like really sour flavor actually experience it just as sour as other people. They simply enjoy it more.”
Notably, researchers saw that both the Italian and American cohorts displayed similar proportions of response patterns to sourness (about 63% to 70 % in the strong negative group and roughly 11% to 12% in the strong positive group), suggesting that these proportions may be stable across cultures.
“Italian food culture and American food culture are so wildly different,” says Sara Spinelli, a researcher from the University of Florence in Italy and first author of the study. “And yet we end up with almost identical percentages, which suggests to us this is not an effect of prior exposure. It’s probably something innately different about those people. We don’t know what that is, but it tells us that it’s not just the foods you grew up with.”
Study authors say that the data supports the existence of previously unexplored taste profiles responding positively to sour stimuli. Considering sourness is classically seen as a negative sensory attribute, researchers were quite surprised to discover that roughly one in eight participants from both countries showed a boost in liking as sourness increased.
“This study highlights the importance of looking at individual differences and potential consumer segments, rather than merely averaging responses across all individuals within a group,” Spinelli continues. “Because when we average the response, all we see is a dislike of sourness, we lose this subset of people who actually love it.”
Prof. Hayes adds that this type of segmentation could be used to develop tailored products capable of accounting for specific “sour liker” taste profiles.
“This could ultimately serve to promote the consumption of healthier foods and beverages that are lower in sweetness but still acceptable to consumers,” the food researcher concludes.