(Originally posted on Sensorium, February 3 2014)
“Most people wildly underappreciate how much their sense of touch influences what they eat”, claims Barb Stuckey in Taste: What You’re Missing (p. 82).
“Mouthfeel” is the word for the touch sensations generated when we eat.
The earlier post “SWEETNESS (AND DEATH)” notes that our sense of taste isn’t confined to our mouth. We also have taste receptors in our pancreas and intestines, for instance.
Similarly, our sense of touch is very diffuse, registering on the surface of our bodies as well as deep within—and often in tandem with other senses.
Diane Ackerman writes:
Touch is a sensory system, the influence of which is hard to isolate or eliminate … Touch is a sense with unique functions and qualities, but it also frequently combines with other senses. (p. 77)
And so we come to “mouthfeel”, where taste and touch overlap.
Stuckey claims that she had not heard the term until roughly 17 years ago. That was when she began work at Mattson, a large North American company that develops new food and drink products.
Mouthfeel is a particularly important concept for food developers, who are often challenged to create low-fat, low-sugar products that nevertheless feel pleasurable and familiar when eaten.
In the past two decades, then, the word “mouthfeel” diffused out of the field of food development and entered general usage.
In fact, the word appeared twice in the weekly food section of the Sydney Morning Herald on January 21 2014. Journalists used “mouthfeel” in an article about wine (Cathy Gowdie, “Is It Uncouth to Serve Red Wine on the Rocks?”), and in another about coffee (Matt Holden, “Mug Shot: The Magic Unpacked”).
Mouthfeel refers to the entire series of perceptions that occur while someone processes a substance in his or her mouth. As Wikipedia says: “It is evaluated from initial perception on the palate, to first bite, through mastication to swallowing and aftertaste”.
That clarifies the difference between “texture” and “mouthfeel”–mouthfeel includes the whole sequence of texture changes during the chewing-up and swallowing of a mouthful of food.
We can experience quite diverse sensations. Stuckey’s list of textural attributes of tomatoes—just one type of food—includes tactile qualities such as “fibrousness”, “mealiness”, and “skin awareness” (p. 87).
Stuckey points out that the molecular structure of food creates texture:
it is the specific arrangement of molecules that makes a banana different from a pretzel. This includes the strength of the bonds between the molecules, the way those molecules change when the food changes temperature in your mouth, and the way the food changes form as it starts to dissolve in your mouth. (p. 86)
Nerves in our lips, teeth, gums, tongue, the roof of our mouth and the inside of our cheeks all contribute to the touch sensations involved in eating.
For example, the trigeminal nerve, associated with pain perception among other tactile functions, detects astringency. You may have experienced astringency—a mouth-drying sensation—when drinking tannin-rich red wine or coffee (p. 88).
Other touch sensations include the heat of chillis, the fizz of carbonated drinks, and the coolness of peppermint, all of which are relayed to the brain by the same nerve (Stuckey, p. 98).
The physical actions of biting and chewing generate still other types of touch. “When you use your teeth to apply pressure to food,” writes Stuckey, “that pressure jiggles the teeth in their sockets ever so slightly, sending information along the nerve fibres to the central nervous system” (p. 89).
Our tongues play several roles, as Stuckey reminds us. Yes, our taste buds respond to the flavours of our food, and, at the same time, touch sensors on the tongue work hard to provide guidance for that organ’s physical contribution to the process of eating: “You use the power and finesse of the muscles in your tongue to move food in the mouth” (p. 89).
Sensations in our mouth also regulate the release of saliva, which both moistens and softens food—making it easier to move and swallow—and adds enzymes that begin the digestive process even before food leaves our mouth.
We also feel when the food is ready to swallow (Stuckey, p. 90).
The texture of a food can reflect many different things: not just whether a food has been chewed enough—or has melted enough—to swallow, but whether a vegetable is fresh or limp, raw or cooked, green or ripe, has been canned or frozen, for example.
In fact, we identify food by touch at least as much as by taste. Stuckey describes an experiment in which everyday foods such as beef, pear, green peppers (capsicums) and brocolli were pureed to the same consistency.
Participants didn’t see the foods, so there were no visual clues. However, they were allowed to smell what they were about to taste. The results were stunning: under half the participants identified these common foods, and only one in five recognised green pepper puree (p. 92).
Food textures—so crucial yet so overlooked—actually help to structure our cultural expectations of dining. Stuckey notes that we are accustomed to certain textural contrasts throughout a meal. A main course may contrast chewy meat with soft mashed potatoes (p. 94).
There are also contrasts from course to course: “dessert is usually a fairly soft affair”, she says (pp. 93-94).
I immediately thought of the different types of softness: mousse, panna cotta, whipped cream, custard, ice cream, jelly, poached peaches. And so many, many more.
Stuckey also talks about textural contrast within one food, noting the “mouth-coating sweet and fatty crème filling tucked between two crunchy cocoa cookies” presented by Oreo cookies (p. 95). Tim Tams have a similar delightful contrast between crunch and creamy.
An unexpected texture contrast, however, can be distinctly unpleasant. Stuckey interviewed a man with no sense of taste or smell:
A walnut hidden in a scoop of fresh yogurt might trigger a gag reflex. Most people would taste the bitterness of the walnut skin, then experience the mouth-smelling that would signal walnut. Fredman doesn’t get those taste and smell cues. To him, a walnut in his yogurt could just as easily be a severed body part of a piece of plastic. (p. 83)
When the texture contrast is expected, however, it can be extremely pleasant. Ben and Jerry’s ice cream, which combines “superhigh butterfat content”—and thus a luxurious mouthfeel—with large chunky, tasty additions (“chocolatey covered potato chip clusters” in their Couch Potato flavour, for example). Stuckey reveals that, behind the brand’s fortuitous combinations, was another man with no sense of smell:
It so happened that one of the founders of the dairy company suffered from … anosmia, the lack of the abilty to smell … Loading up their ice cream with swirls, chunks, fruit, and other inclusions gave the founder a little compensation for what he was missing. (p. 85)
The “super premium” ice creams, with high fat content, tap into human’s love of fat—a passion so strong that it presents a rare instance of “mouthfeel” that bursts into our awareness. As Stuckey says:
we can—and do—derive great pleasure from food texture. Yet when we remember food experiences, it’s rare that texture is at the top of our minds, except perhaps when something is extraordinarily high in fat. (p. 84; my emphasis)
Fat not only coats the tongue—which stimulates the sense of touch—it simultaneously enhances taste and “carries flavour around your mouth” (Stuckey, p. 99).
Our greedy reactions may be an evolutionary adaptation left over from the days of hunter-gathering, when every single calorie was needed (Stuckey, p. 95).
Good-o! Can I add some whipped cream to your super-premium ice-cream?
• What are your food aversions? Is it taste or feel that makes you gag on them?
While the feel of food is often a source of pleasure, it can trigger other reactions.
Long-time New Orleans food writer Tom Fitzmorris describes eating raw oysters for the first time. He overloaded his palate with crunchy crackers and spicy sauce, “trying to buffer the cold, unique flavour and mouthfeel of the oysters” (p. 27). (He soon conquered his squeamishness.)
I also avoided oysters for many years, partly because of that mouthfeel. Then I discovered I love them.
My brother, when young, hated “slimy” food, including casseroles, and I remember his violent projectile vomiting when “encouraged” to eat a soft-boiled egg.
• It just seems wrong, somehow.
How does a hamburger feel? An experimental hamburger made from muscle tissue grown in a laboratory apparently “feels” just like a regular burger when it is chewed. The thought that it feels real makes me squeamish—much more than if I were told the lab burger tasted like the “real thing”.
I guess that shows I accept that it’s easy enough to fake the flavour, but a real-feeling hamburger is somehow on the borderline between living and non-living … Well, that’s on another plane altogether.
Read the article: Alok Jha, “First Lab-Grown Hamburger Gets Full Marks for ‘Mouth Feel’”, August 6 2013, The Guardian.
• There must be fifty ways to feel your pinot: learn how to identify and describe mouthfeel sensations with a “mouthfeel wheel” for red wine.
Read the article, which includes the wheel: Richard Gawel, A Oberholster, and Leigh Francis, n.d., “A ‘Mouth-feel Wheel’: Terminology for Communicating the Mouth-Feel Characteristics of Red Wine”.
See also here. Principle developer Richard Gawel is now a research scientist at the Australian Wine Research Institute. He explained:
Just listen to red wine consumers when they explain why they like, or don’t like, a particular red wine. Wines that they perceive as “soft” and “smooth” in the mouth are frequently at the top of their shopping lists. This convinced me of the merits of compiling an extensive list of defined terms that could be used by wine-tasters to describe red wine texture.
The team tasted hundreds of red wines, and noted how they felt in their mouths:
Falling into the main classes of astringency, acidity, body, texture, heat and irritation, the terms were initially selected by considering the mouth-feel sensations perceived during the tasting of hundreds of red wines of varying varieties and ages from Australia, Italy and France. After further tasting and consultation with some of Australia’s most experienced red winemakers, wine educators and red wine researchers, the final list of terms contained in the wheel were chosen and grouped. Chalkyness, furryness and chewyness were some of the more unusual textures perceived in some of the wines, while the sensations of silkyness, sappyness and dryness were others that were more frequently encountered by the tasters.
A Canadian expert has now developed a white wine mouthfeel wheel. See Tara Q Thomas’ article, “The Mouthfeel Wheel”, in US Gourmet magazine, July 25 2008.