Taste: Surprising Stories and Science About Why Food Tastes Good (19 page)

To measure the acidity (sourness) of any food, we can easily test it with an instrument. A pH meter gives us an indication of how acidic a food is going to taste. There are plenty of ways to measure texture, but it’s not as simple as pH because there is no single instrument that measures texture across all foods. A trained human taster works better on more foods than any instrument.

In our food lab at Mattson, we have a texture-reading machine called an Instron. This piece of equipment allows us to test the crispness of foods such as egg rolls, chicken wings, and potato chips. It measures the force that’s necessary to puncture through the outer shell or crust. But this machine doesn’t work with fluids, because you can’t puncture liquid. For liquids, there’s a Bostwick Consistometer.
This piece of equipment looks like a gated dam. You pour a fluid food or beverage into the chamber at the top, open the floodgate, and record how fast the product flows down an angled slide. But this piece of equipment wouldn’t work at all with a chicken wing, which doesn’t flow. A Brookfield Texture Analyzer allows you to measure the texture of both solids and liquids, by inserting a probe into them. How easily the probe spins or punctures can tell you a lot about the food, such as ripeness, firmness, hardness, and gel strength.

Even when we can measure texture, it doesn’t tell us whether that texture is good or bad, acceptable or unacceptable. A 5.5 score on the Bostwick scale is relatively useless until it is correlated with what scores are acceptable for a given type of food. Again, this needs to be done by a human being. Machines can give us numerical scores, but they can’t tell us what savors good or bad.

Pioneering food texture researcher Alina S. Szczesniak explained that our love of contrasting textures has a biological basis:

All people begin by consuming liquids and (essentially) all people advance to biting and chewing of solids. The sequence, liquid before solid, and the contrast between the passive sensation of liquids . . . and the active ones of biting and chewing is fundamental and creates boundaries to texture experiences and combinations.

Good chefs go to great lengths to add texture contrast to their plates, utilizing four different approaches: within a meal, on the plate, within a complex food, and within a simple food.

Contrast
within a meal
refers to the varying textures that occur as a meal progresses. For example, a meal might start with the smooth, easy, comforting texture of a pureed cream of mushroom soup. This eases you into the meal with a food that requires very little energy to enjoy. You simply spoon it in, swish it around (if you want to get the most flavor out of it), and swallow. From there the meal might progress to a crisp, fresh romaine salad, tossed with a creamy dressing and topped with crunchy toasted nuts. By the time the main course arrives, you’re warmed up enough, texture-wise, to take on the firm chew of a New York strip steak or toothsome lobster. When the savory courses are over, dessert is usually a
fairly soft affair, again, which closes the parentheses of the meal as effortlessly as it began. Hard textures in a dessert course, such as the crisp flamed top of a crème brûlée, are usually reserved for garnishes, when it comes to dessert, lest the meal close with too much violence. Most diners prefer a soft landing.

Within the meal, there’s also texture contrast
on the plate.
Let’s take that New York strip steak, for example. The classic pairing of steak and mashed potatoes has (in part) to do with the fact that the soft, yielding potatoes—whipped with butter, cream, and, if you’re exceedingly fortunate, crème fraîche—provide a foil for the tougher steak. Your jaw uses energy to chew the hunk of steak, and is subsequently rewarded with a forkful of soft potato that requires little more effort than pressing it against the roof of your mouth and swallowing. Effort, reward; effort, reward. A side of onion rings might gild the textural lily with firm yet crunchy onions inside a coat of crispy fried buttermilk batter.

Craig Stoll, chef-owner of the famed Delfina restaurant in San Francisco, layers texture into a complex dish by adding the same ingredient at different times as it’s cooking. Stoll says:

We do this one risotto with crab and radicchio. We add the radicchio at two stages. First, we throw it into the pot at the beginning with oil and garlic—a whole clove that we pull out. We’ll sauté it and caramelize the radicchio a little bit to develop some sugars. And then we’ll build the risotto into that. We’ll take the rice and add it and then we’ll cook it and work it and add the crab. Then we’ll add more radicchio two-thirds or three-quarters of the way through the cooking so that you’ll have more texture. You’re layering in texture at a couple of different stages in the dish.

Sometimes getting a texture you aren’t expecting is frightening, as it can be for Cameron Fredman, the attorney who cannot taste or smell, but sometimes it’s a delight. Creative chefs such as Heston Blumenthal of The Fat Duck in England, Wylie Dufresne of wd~50 in New York City, and Grant Achatz of Alinea in Chicago like to rethink and reengineer familiar foods to surprise and delight diners. By aerating a food, they can change the texture of something that’s usually hard, crunchy, or crispy into foam or “air” that melts quickly on the tongue. Aerating rich foods such as foie gras delivers the same intense flavor without the fill factor.

Cyrus’s Douglas Keane’s Five Tastes Tower beer bubble started with Racer 5 India Pale Ale, to which he added lemon juice, honey, salt, and sodium alginate. Just before serving it, he dropped it by the tablespoonful into a bath of
gellan gum, water, and sodium hexametaphosphate, which formed a semisolid shell around the drop of beer. When I put it in my mouth, the bubble transformed instantly to liquid. Without Keane’s manipulation and use of high-tech ingredients, the beer would have been a singular, familiar homogeneous liquid texture. With his artistry, the texture became something altogether different. As Szczesniak says, “The abrupt change from a solid to a liquid state is very pleasurable.”

But don’t think that this type of culinary skill (or pantry of six-syllable ingredients) is required to demonstrate texture contrast
within a complex food.
Simply reach for the nearest Oreo cookie. There’s perhaps no better example of texture contrast within a food than the mouth-coating sweet and fatty creme filling tucked between two crunchy cocoa cookies.

Texture contrast
within a simple food
is the type of contrast that happens over time as the heat from your mouth changes a food’s texture, without your needing to apply force or energy. As all chocoholics know, you can simply place a piece of good-quality chocolate on your tongue, close your lips, and revel in the blissful change of texture from solid to liquid: jaw, tongue, and teeth are not required. Sucking on a piece of hard candy or an ice cube results in the same type of temporal (time-related) texture contrast, from solid to liquid, yet these examples are obviously inferior to chocolate if you want to demonstrate the effect quickly (and indulgently).

Rutgers’s Paul Breslin believes that we innately enjoy this type of solid-to-liquid texture change because it usually indicates the presence of fat, which is an incredibly efficient source of calories—exactly what you need when you’re hunting and gathering. In fact, fat is more than twice as calorically dense as carbohydrates and proteins. Of course, we don’t need those extra calories when we’re hunting for a parking spot closer to the mall entrance or gathering dust on our couches each night. Yet this evolutionary reaction to fat is still with us. If you concentrate on how fatty foods like butter, cheese, and ice cream behave in your mouth, you can savor how pleasurable that shift—from hard or frozen to soft and creamy—feels. There’s absolutely nothing like it.

American-style chocolate pudding—the kind of dessert that Jell-O brand makes—is made from milk cooked together with cocoa, sugar, and starch until
it thickens up. The key thing about this type of pudding is that it’s the starch that gives it its texture.

In her lab at the Monell Chemical Senses Center, Abigail Mandel, a postdoctoral fellow from 2009–2011, put a dab of something magical into a texture-reading machine along with the pudding. When this amazing substance came into contact with the starch in the pudding, it “pulverized” it, said colleague Paul Breslin, meaning that it almost instantly changed the pudding from a thick, viscous texture into something thin and almost watery. The something they added to the pudding was spit. That’s right: human saliva.

Before we go any further, I should clarify how they harvested the saliva for use in their experiments—because that was the first thing I wanted to know.

“We just have people drool into a cup,” said Breslin, without a shred of humor in his voice. He went on to explain that this finding gives us enormous insight into why we like the foods we like. As with so many things, it goes back to genetics.

There’s a gene that determines how much of a substance called
amylase
your saliva contains. The more copies of this gene you have, the more pulverizing amylase you have in your saliva. If you have lots of copies of the gene, and hence lots of amylase, you are going to notice a texture change in pudding much more quickly, and perhaps intensely, than someone who doesn’t. Because texture contrast within a food is desirable, you may get more pleasure out of thick, starchy foods than someone who doesn’t have as much amylase in his or her saliva.

Consider your reaction to low-fat foods that are thickened with starch, such as pudding, American-style fat-free yogurt, or low-fat ice cream. It could be that your high level of amylase makes you less enamored of these foods because they just don’t give you the same glorious texture transformation you get from higher-fat versions.

Mandel, the lead on the experiment, adds, “On the other hand, people with high amylase do produce significantly more maltose and glucose in the mouth during starch breakdown [meaning their saliva produces more sugar in the mouth when they eat these things], so it’s possible that this group finds starchy foods more rewarding and, therefore, likes them more.

“The question of how this perception affects preference and liking for starch-thickened foods is where things get tricky,” explained Mandel. “It’s likely that an individual is used to his own ‘starch viscosity experience.’ Generally, people like what they are used to, at least in terms of texture, so it’s possible that
both high-and low-amylase people equally enjoy the texture of starchy foods, even though the experience will be totally different for each individual.”

Gary Beauchamp is the director of the Monell Chemical Senses Center. In the course of his research on taste and smell, he has tasted ibuprofen on purpose, unlike most of us who swallow it whole—and if we taste anything at all, it’s the cinnamon coating that brands like Advil apply to the outside of the pill to mask its taste. That’s because ibuprofen is very bitter and causes a distinctive sting at the back of the throat. Beauchamp knew this sensory profile well.

One year Beauchamp was attending a molecular gastronomy seminar in Sicily and made a startling discovery about olive oil. Even if you are an aficionado of extra virgin olive oil, you may not have experienced its true essence, which can be captured only minutes, hours, days, or weeks after its virgin pressing. The green blood of olives smells of freshly sprouted flora infused with the newness and glory of life itself. It smells so vibrant that you want to dab it on your wrists, bathe in it, and pour it atop whatever you’re eating. There is no scent like it on Earth. I am lucky enough to have friends who have olive trees. I gladly trade hours of my labor picking their olives for one precious, coveted bottle of freshly pressed oil. Roger and I sop it up with bread and sprinkle it on everything in the few days after it’s bottled and before it disappears. It quickly loses that vibrancy with age or improper handling. (The worst sin is to store olive oil near a source of heat, where it will not only lose its green top notes but also turn rancid.) Beauchamp had never tasted olive oil this fresh until his trip to Sicily. There, he took a swig of some fresh-pressed oil and was instantly intrigued.

Beauchamp said, “I had considerable experience swallowing and being stung in the throat by ibuprofen from previous studies on its sensory properties. So when I tasted newly pressed olive oil I was startled to notice that the throat sensations were virtually identical.”

This throat sensation is a signature of freshly pressed olive oil. It hits you in the back of the throat and lingers well after you swallow. Because it reminded him so much of the sting of ibuprofen, Beauchamp decided to study it further to see if olive oil might have some of the same anti-inflammatory properties as ibuprofen. He did and it does. The low rates of heart disease, stroke, and some cancers
in Mediterranean countries may be due in part to ingesting large amounts of olive oil that contains these anti-inflammatory properties.

When something stings, tingles, cools, or burns your tongue, mouth, or throat, you are experiencing chemesthesis. The compounds that provide chemesthesis are literally irritating—not necessarily in a bad way, but they stimulate the same nerve that carries pain information to the brain, the trigeminal nerve. I call them
Irritastes
and they include the spicy-hot heat of jalapeños, ginger, and cinnamon; the sting of carbonation; the cooling from menthol or mint; and, of course, the signature sting of extra virgin olive oil.