Salty, sweet, bitter and sour: a balanced meal?

Salty, sweet, bitter and sour: a balanced meal?

(Originally posted on Sensorium, October 28 2013)

Strangely, Diane Ackerman’s section on taste in her wonderful A Natural History of the Senses pays much attention to food, food rituals and food symbolism (pp. 127-172), but little to the actual experience of tasting. This intrigued me, because taste is a sense that gives us great pleasure. Even so, there is a kind of irony there. We often eat unthinkingly; the true abilities of our sense of taste go unused and unnoticed.

When I began looking into taste, I soon learned a whole heap of interesting things. Here are 12 things that convinced me I needed to pay more attention to what was going on in my mouth.


Taste is the weakest of our senses: “Smell is estimated to be ten thousand times more sensitive than taste”, writes Martin Lindstrom in Brand Sense: Sensory Secrets behind the Stuff We Buy (p. 36).


“Do animals taste the same things as humans?” This intriguing question is answered on the Australian Broadcasting Corporation science website, which tells us that adult humans have approximately 10,000 taste buds, and chickens only 30.

But if you think that makes humans superior beings, think again: Diane Ackerman points out that rabbits have 17,000 taste buds and cows have 25,000 (p. 138).


Ackerman also writes that butterflies and blowflies can taste with their feet (p. 137); the ABC notes that fish taste with their skin, and although we think we taste with our tongues, our taste buds are also in our throats, on the roof of our mouth, and on our voice box. So, according to Ackerman, people who—for some reason—don’t have a tongue are still able to taste (p. 140).


Our taste buds wear out every seven to ten days, and as we age, the replacement process becomes less effective. The Wikipedia article on “Taste” says that, by 20, we have already lost half our taste receptors. Not surprisingly, babies taste things very intensely.


Different areas of our tongue are particularly sensitive to different flavours. We are most receptive to sweetness on the tip of our tongue, and we are best able to taste bitterness at the back of our tongue. We detect sourness on the sides, and taste saltiness all over.

We can sense bitterness in extremely small amounts, one part to two million, says Ackerman. By comparison, sourness can be discerned in one part to 130,000; saltiness at one to 400; and sweetness at one to 20 (p. 139).

This  means that, at the point when we can taste salt and sugar, there are already quite high levels of salt and sugar in our mouth!


In the Western world, sweet/sour/bitter/salty are considered four of the most “basic” components of flavour. It used to be believed that the four basic types of taste combine to give all the different taste experiences that we enjoy (or don’t enjoy)—in much the same way that the rods and cones in our eyes allow us to see all the shades of colour.

Now, however, it is clear that “flavour” is created in our brains—a perception—when impulses from our taste receptors are mixed with smell messages from the olfactory nerves, which are stimulated when the gaseous “volatiles” given off by food are transported up the back of the nose.

People who lose their sense of smell can only taste sweetness, saltiness, sourness and bitterness—bland and straightforward, and not in any way resembling the glorious, complex flavours that so excite our appetites and stir our memories and our emotions.

Barb Stuckey’s highly recommended book Taste: What You’re Missing explores the complex interactions between physiology and culture that create our sense of taste. As well as the olfactory nerve, she says, eating triggers the chorda tympani and the glossopharyngeal nerves, which send taste information from, repectively, the front and back of the tongue. The trigeminal nerve is also stimulated to communicate sensations of texture, pain, and temperature, all of which become part of the complex, integrated experience of taste (p. 59).

7. Since 2009, scientists have widely accepted that there are more than the four basic taste-types. They now include “umami”, borrowed from a Japanese concept, referring to a savoury, meaty flavour (soy sauce, mushrooms, cheese). “Fatty” is also considered by some to be a flavour-type, and scientists are studying others like “metallic” and “soapy”; see Barb Stuckey’s chapter “Fat: The Sixth Basic Taste—and Other Candidates” (pp. 260-266).

(Yes! Both of these types of taste are also represented in the photograph above. Fish and chips is a balanced meal, from one point of view.)


It makes sense, but I hadn’t actually thought about it: different cultures and different eras have different classifications of taste.

David Howes, in his introduction to Empire of the Senses: The Sensual Culture Reader, tells us that Jacob Boehme, a 16th-century theologian, believed that life itself arose from the “flavour forces”: sourness, sweetness and bitterness (p. 5).

The Chinese understanding of taste includes “spiciness”, says Wikipedia. The ancient Indian Ayuvedic approach to food and healing suggests six categories; in addition to salty, sweet, bitter and sour, it includes categories for pungent and astringent.


As noted earlier, the back of our tongue is sensitive to bitterness—and our ability to detect bitterness is very high. These may be clever evolutionary mechanisms to help protect us from poisons, many of which are bitter. When the back of the tongue is stimulated, we can gag—it’s a reflex, and could just save us from swallowing something dangerous.


Our sense of taste weakens at high altitudes. Journalist Robert Upe interviewed celebrity chef Luke Mangan, who has created meals for Virgin Blue business-class customers. Mangan says: “In our restaurants we have a tuna dish that we steam with tomato salsa and black olives, but for flight we need to add more sharpness, acidty and kick to it because we lose that [taste] sensation up in the air.”


Back to the ABC’s “Do Animals Taste the Same Things as Humans?”, where we learn the interesting fact that cats can’t taste sweetness.

(Hmmm. Does that account for the phrase “sourpuss”?)


Colgate has patented the flavour of its toothpaste, writes Martin Lindstrom (p. 37).

Now, to me, different types of Colgate toothpaste taste different. Is my tongue misleading me?



Babies have more taste buds than adults, and taste foods more intensely.

In addition, as they are introduced to new foods, they discover the universe of flavours–some enjoyable, some not so much, but the encounter is always shocking in its newness.

This YouTube clip shows children (not all babies) trying a variety of foods for the first time. The slow-motion video allows us to see the entire sequence of facial responses to these new experiences.

Here are babies trying various yummy-sounding purees, with mixed results: peach, apple and pear puree, and green-pea puree.

You might think that ice cream would be universally liked, but these babies’ faces show they are challenged by their new experiences. This baby took to it immediately, but this little girl wasn’t so sure at first.

So when it comes to exposing young children to strong sour, bitter or spicy foods, sometimes videos of the babies’ first experiences seem close to child abuse, especially since the adults watching and recording are usually laughing.

But I admit that the kids seem to come out of it okay.

In fact, I often join in the laughter when I watch these videos, but I kind of hate myself for laughing at the poor kids.

As I watch them innocently putting the lemon slices in their mouths, I feel their trust is being betrayed and that they are in danger of losing faith in the goodness of adults. And learning that life can be bitter as well as sweet, and they’re too young for that!

By the way, there are heaps more of this unsettling type of clip on YouTube: babies trying lemons; a baby trying wasabi; another youngster trying wasabi.

With our depleted tastebuds, we adults don’t have such intense first-taste experiences. Can you remember a first taste of anything? It might be something you tried as a kid, or something new you have encountered as a grown-up.

I remember hating the “stink-bug” flavour of the herb coriander (cilantro), until I ate it sprinkled on noodles in Thailand—maybe because it was in a balanced combination with other Thai flavours. Not too long after that, I had a curry in India that also had coriander liberally strewn over it. Travel certainly broadens the palate, as well as the mind!

  • Diane Ackerman, 1990, A Natural History of the Senses, Vintage: Random House, New York.
  • Australian Broadcasting Corporation, 2013, Do Animals Taste the Same Things as Humans? Ask an Expert (ABC Science).
  • David Howes, 2005, Introduction, Empire of the Senses: The Sensual Culture Reader, ed. David Howes, Berg, Oxford, pp. 1-17.
  • Martin Lindstrom, 2005, Brand Sense: Sensory Secrets behind the Stuff We Buy, Free Press: Simon & Schuster, New York.
  • Barb Stuckey, 2012, Taste: What You’re Missing: The Passionate Eater’s Guide to Why Good Food Tastes Good, Free Press: Simon & Schuster, New York.
  • Robert Upe, “Virgin Flight Attendants Get Classier Thanks to Celebrity Chef”, Sydney Morning Herald, May 8 2013.
  • Wikipedia, 2013, “Taste”.

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