Taste: Surprising Stories and Science About Why Food Tastes Good (40 page)

If you were to taste sugar, sucralose, aspartame, acesulfame potassium, stevia, and honey in succession, you’d understand how complex the seemingly simple Basic Taste sweet is. When you do the Sweetness Profile exercise at the end of the chapter, pay attention to the three phases of what you’re tasting. The first phase is what we call the
up-front
taste, which occurs at the very beginning. This refers to how fast the sweet taste registers with your brain. You’ll notice that the speed with which you taste each sample’s sweetness varies greatly. The second phase is what happens after the taste registers. This is the
middle
of the taste profile. How much does the sample fill your mouth? Does it taste thin? Bitter? Where does the taste hit on your tongue? The last phase, or the
finish
, happens after you swallow
and the taste starts to fade away. Many artificial sweeteners have a very long finish, which means that their taste remains in your mouth for a long time.

A Simulation of Sweetness Time and Intensity Curves

Look at the graph of the sweetness time and intensity curves. Notice that sugar (thickest line) takes a while to come on. It builds up in your mouth much more slowly than aspartame, which knocks you over with an immediate sweetness. Notice also that sucralose is still screamingly sweet long after the sweetness of sugar, aspartame, and aceK have peaked and started to decline. This difference in the timing and intensity of how you experience sugar and
nonnutritive sweeteners
is why many people find that the nonnutritive sweeteners don’t taste quite right.

One of the ways that companies like Coke get around the different timing and intensity curves is by blending more than one sweetener together. Doing this allows one sweetener’s curve to fill in the peaks and valleys of another’s, smoothing them out. The blend of aceK and aspartame that’s used in Coke Zero moves the sweetness hump a bit more in the direction and shape of the sugar curve. This is probably why Coke Zero was one of Coca-Cola’s most successful new product launches. Its sweetness profile more closely resembles “the real thing.”

Even if you were able to prove that a blend of the sweeteners aceK and aspartame makes diet cola A taste exactly as sweet as sugar-sweetened cola B, you’d
still come up short, because sugar adds more than just the Basic Taste sweet. It also contributes to mouthfeel.

Sugar sweetness is measured using an instrument called a refractometer, which measures the Brix, or the amount of solids in a food, which correlates with sweetness. The higher the °Brix, the higher the solids, and the sweeter the taste. Think of how Concord grape juice (for example, Welch’s) feels in your mouth: sweet, sour, and a tiny bit tannic. Now consider grape jam; it’s a completely different textural experience although it has the same flavor profile: sweet, sour, and a tiny bit tannic. The difference between grape juice and grape jam is the amount of sugar and water, and the stiffness of the gel formed by pectin. The juice has much less sugar, and hence a lower °Brix. Welch’s Concord grape juice has a Brix of 15° while Welch’s grape jam has a Brix of 65°. The fourfold increase in Brix is one of the things that make the jam feel much thicker on your tongue.

Brix refers to both sweetness and thickness, which are related. You’ve experienced increasing Brix if you’ve ever oversweetened a cup of hot tea or coffee. As you add sugar one teaspoon at a time, it slowly dissolves into the tea. The more sugar you add, the thicker the tea gets. If you got lost in thought and continued to add teaspoon after teaspoon, eventually you’d end up with a thick, syrupy drink. With sugar, an increase in viscosity accompanies an increase in sweetness.

When you take the sugar out of a cola and replace it with an infinitesimal amount of a nonnutritive sweetener such as aspartame or saccharin, you lose all the Brix from the sugar and hence you lose some of the mouthfeel. Artificial sweeteners are used at such a low level that they don’t increase the amount of solids in a drink, which is also why they’re called
nonnutritive.
They’re used at incredibly low levels and they don’t provide any nutrition or calories. The result is a beverage with less body. Tab, Diet Coke, and Coke Zero all lack the satisfying mouthfeel that bulky sugar provides.

The foods that generally trigger our sweet taste receptors are carbohydrates, the simplest of them being sugars. But not all creatures crave carbs.

My cat G.G. is as sweet as sugar. She’ll sit in my lap and cuddle with me for hours during a movie. If you offer her your hand, she’ll lick it clean with her
sandpaper tongue, whether it needs a washing or not. She’s generally a canned food kind of cat who turns up her nose and leaves the room if I ever dare offer anything but her beloved Fancy Feast. But one morning I heard G.G. crunching on something hard that she was thoroughly enjoying. When I asked my sweetheart kitty, “What are you eating, G.G.?” she stopped chewing and spit out the head of a mouse.

A few hours later, still disturbed by the image, I wondered:
Does she really find dead mice delicious
? They’re furry, full of bones, and raw. Yuck. I can understand that a mouse might taste good if I were starving and built a fire to make a rosemary rotisserie mouse. But a raw, stringy mouse? Sounds horrible.

If G.G. were able to talk, she might have the same reaction watching me eat Swedish Fish, a chewy confection that’s neither Swedish nor marine. These fish-shaped, fruit-flavored candies are almost pure sugar, and I adore them. They return me to my childhood, when my mother used to let us buy them at Morrow’s Nut House before we went to the movie theater at the mall. But G.G. is a carnivore who has evolved to eat only meat. Somewhere inside that peanut-sized kitty brain of hers is a reward system that says
“YUM! Raw mouse! Delicious! Sustaining! Protein! Fat!”
Sugar holds no appeal for her. Since cats don’t need it for nutrition, they have lost the ability to taste sweetness.

Humans, on the other hand, crave sugar.

When you put something sweet in your mouth, the insulin level in your body spikes. This is a cephalic phase response to what your body assumes (from the
sweet taste) will be incoming carbohydrates. It’s essentially a reflex. Your tongue signals
sweet
to the brain, which communicates to your gut:
Food is coming; prepare for work.
Then acidic digestive juices start flowing.

What happens when the brain senses something sweet that doesn’t provide calories? This question has led to much research into the effects of nonnutritive sweeteners such as aspartame and sucralose. Some people believe that sugar-free sweeteners interrupt the natural taste/eat/reward system. Others think these sweeteners can be used specifically for their deceptive sweetness, to allow you to make do with fewer calories without giving up sweetness in your diet. Dozens of studies failed to provide consensus on whether use of these sweeteners leads to weight gain or loss. Nonnutritive sweeteners probably make consumers prefer higher sweetener levels in foods and beverages, but we don’t know whether this leads them to eat less and lose weight.

I believe that you can teach yourself to like things less sweet. Once your palate has become used to a norm, you have to slowly reset it. For example, I drink a cup of hot tea every morning when I wake up. I used to sweeten it with two packets of high-intensity sweetener. Then one day while doing research for this book, I realized that I was drinking the sweetness equivalent of four teaspoons of sugar each morning and decided to cut back. When I first tried to go lighter on sweetness, I felt I was missing something. Each morning I dreaded making my one-packet tea, which no longer gave me the same sensory stimulation I was used to. So I decided to try a different tack. I switched from sweetener to honey, which adds not just the sweet taste, but also a lovely floral aroma. I was tricking myself by replacing some of the sweet taste with another sense: smell. Honey also boosts the mouthfeel of tea by adding more Brix solids than I was getting from my sweetener. By doing this, I replaced a bit more of the sweet taste with another sense: touch. Today I’m drinking a much different cup of tea: less sweet but equally satisfying.

Retraining your palate to like things less sweet is one of the secrets to eating a more healthful diet. It will be startling at first, but once you figure out how to swap one type of sensory stimulation (the sweet taste) for another (smell and texture) and appreciate it for its own sensation, you won’t miss anything at all. The key is developing awareness and appreciation of sensory stimulation beyond sweet. If you find yourself drinking or eating something really sweet, you can kick your lazy palate into gear by using other points on the Sensory Star, as well as other Basic Tastes.

Regardless of where you live, how you were brought up, or whether you’re a HyperTaster, Taster, or Tolerant Taster, in general, you like the taste of things that are sweet. You may not like intensely sweet foods—like Swedish Fish candy—but it would be odd for anyone to taste sugar and say it is unpalatable. We’re highly tuned to three sweet molecules—sucrose, fructose, and glucose—because they provide quick, easy sources of energy (otherwise known as calories). Back in the days when our ancestors were trying to feed their families by hunting and gathering, they needed all the calories they could get. Hunting for game was hard. Refining starches was time-consuming. But fruit was a no-brainer. It was sweet and you didn’t have to strip, skin, cook, mill, or ferment it. If you found a piece of fruit, you’d found a good source of food that immediately fed your hunger.

People so universally love the sweet taste that making foods sweeter is an easy, but lazy, way to make them more palatable. Most of us Americans would rather eat overly sweet foods than explore the other tastes that come out when sweetness levels are lowered. But this is beginning to change. Milk chocolate in the United States used to be available in only one level of sweetness: Hershey’s. Nowadays you can find dark milk chocolates or semisweet milk chocolates in supermarkets, and premium chocolatiers such as Michael Recchiuti and Vosges are growing in popularity. I have a huge fondness for Hershey bars from my youth (spent within driving distance of their chocolate factory), but my chocolate tastes have grown up. So have Hershey’s. In 2005, they purchased artisan chocolate maker Scharffen Berger, which offers an “extra rich milk chocolate” that tempers its sweetness with the bold bitter counterpoint of 41% cacao.

I think of sweetness as one point of the Taste Star that requires a counterpoint, or several, to be really crave-able. The most logical counterpoint to sweetness is sourness, and these two occur together in perfect harmony in nature. When fruit ripens to the perfect balance of sweet and sour, it’s usually at its nutritional peak.