Soup and a Side of General Relativity

As a chef, Nathan’s passion for creating new dishes is twofold—he creates dishes and the dishes they’re served on. When thinking about a new bowl to create for a 2014 dinner, he found inspiration from a source not often associated with food: the general theory of relativity. The vessel, which is designed to hold two vibrantly colored soups, has a unique shape. Until recently, the bowl might have appeared to be an intricate spiral, but now, the inspiration for its shape—gravitational waves generated by two colliding black holes—has been receiving international attention.

Modernist Cuisine Gravity Bowl

Last week, news broke that on September 14, 2015, the LIGO Scientific Collaboration, a network of scientists from 15 countries, detected gravitational waves for the first time ever. Naturally, the Modernist Cuisine team was excited by this monumental discovery. In honor of Nathan’s cosmic muse, it seemed like a fitting time to share the story of his “gravitational waves” bowl.

In 1915, Albert Einstein came up with the general theory of relativity—in short, it theorizes that gravity is due to the warping of space–time. It was a radical idea for the era, but in 1916 he proposed yet another radical idea with the prediction of gravitational waves, ripples in the curvature of space–time that propagate from their source at the speed of light. He expanded his theory by positing that gravity is made of waves, just as radio signals are made of waves of electromagnetic radiation.

Photo credit: R. Hurt/Caltech-JPL
Photo credit: R. Hurt/Caltech-JPL

About 1.3 billion years ago, a system of two black holes orbited each other and emitted gravitational waves along the way. They eventually coalesced into a supermassive, spinning black hole, and for decades scientists have looked for evidence of its gravitational waves, but to no avail. Amazingly, the LIGO team figured out a way to not only detect gravitational waves but to also prove it was two black holes that produced them—a momentous discovery that helps confirm Einstein’s theory.

Well before Nathan began working on Modernist Cuisine, he spent his days researching general relativity and quantum theories of gravitation. Although his career took him down another pathway, his interest in those subjects remained and would continue to influence his work in new ways. The book Gravitation, for example, influenced the design and approach of Modernist Cuisine. Coauthored by Kip Thorne, one of the founders of the LIGO project, it’s a landmark in the study of gravity.

It’s no wonder Nathan found inspiration in the cosmos yet again. When he thought about colliding black holes in the spring of 2014, he didn’t just see gravitational waves—he also saw an otherworldly bowl that would make two soups spiral around one another.

Modernist Cuisine Gravity Bowl Aluminum 3-D model

To design the bowl, Nathan used Wolfram’s Mathematica to create a mathematical model that mimicked the gravitational waves of orbiting black holes just before they merge. Next, the Modernist Cuisine team turned Nathan’s Mathematica surface into a 3-D model using the machine shop’s five-axis CNC mill to carve the prototype out of solid aluminum.

Modernist Cuisine Gravity Bowl Plaster Mold

From there, the aluminum 3-D model was used to make a negative mold out of plaster.

Modernist Cuisine Gravity Bowl Mold

Local Seattle potter Wally Bivins then made porcelain bowls from the plaster mold by using a technique called “hump molding.” The clay is rolled into a sheet and tamped down over the mold so that the top surface of the plaster mold becomes the soup-side of the bowl. The soft clay bowl is fired in a kiln and glazed, which transforms it into a bright white porcelain dish.

Modernist Cuisine Gravity Plate

Even before the announcement last week, we liked the story behind the gravitational wave bowl because it illustrated that the source of culinary creativity can come from anywhere—even outer space. Before, we were able to tell guests about a bowl inspired by Einstein’s theories. Now we look forward to telling Cooking Lab visitors that we serve soup from what will surely be one of the most important scientific discoveries of our time.

So, remember: if you’re ever at The Cooking Lab, those aren’t noodles in your soup—they’re ripples in the fabric of space–time.

Good Eating in An Exoskeleton

The winter holidays are often celebrated with glorious roasts. But there’s another staple of Christmas and New Year’s fare: crustaceans. From country to country and coast to coast, it’s all about seafood.

In Australia, barbecued or steamed prawns (referred to as shrimp in the US), Australian crayfish, and marron take center stage on the table for Christmas dinner, a trend that is being echoed in the United Kingdom, where more and more families are replacing traditional turkey with large lobsters. Seafood is staple Christmas Eve fare, but most notably in Italy where the night is known as la Vigilia. Also referred to as the Eve of Seven Fishes in the United States, the night culminates around the kitchen table, which is set with course after course of dishes laden with a variety of fresh fish and crustaceans. Lobster, in particular, has become a Christmas Eve and New Year’s Eve tradition (despite some cultural superstitions) for many families throughout the world and, along with crab and prawn, is a staple of Réveillon, celebrated in France, Belgium, Brazil, Portugal, Quebec, New Orleans, and other areas with French or Portuguese influence. The food at réveillons, long dinner parties preceding both Christmas and New Year’s Day, is luxurious, extravagant, and comforting—a mix that is well suited for delectable crustaceans.

Lobster Disrobed

Selecting crustaceans

Although cooking crustaceans isn’t terribly complex, picking the right ones for the pot can be a challenge. You’ll do better armed with the knowledge that when crustaceans grow, they periodically shed their exoskeletons; that is, they molt. Many cooks know to avoid crustaceans that are getting ready to molt, but you may not know when to chase after those that have already molted.

Timing is important here because prior to molting, lobsters and crabs shed a large amount of muscle mass. They literally shrink inside their shells. After the exoskeleton weakens, they break out of it, living briefly without any protective covering at all. Just after molting, they pump up, adding 50%–100% to their body weight by absorbing water. You don’t generally want to eat a crustacean that is about to molt or that has just molted and is taking on a lot of ballast. The exception is soft-shelled crab, which is cooked just after having molted.

Once their new shells begin to harden, crustaceans are perhaps at their best for the table. Many say that a lobster with a new exoskeleton is exceptionally sweet and firm. Likely, this is because the creature ate voraciously after molting to replenish its protein and energy stores in order to rebuild its protective armor.

What to look for

1. Look at shell color and firmness:

When crustaceans are at their prime for eating, their topsides will be deeply colored, and their bellies will take on a stained or dirty look. The shell should be firm to the touch. Crustaceans are primed for cooking when their shells will have become very hard.

2. Compare size to weight:

Crustaceans will feel heavy for their size because they are filled with dense muscle tissue, not tissue that is bloated with absorbed water. Crustaceans that are about to molt feel the lightest because their shells are partly empty.

3. The shell will also give you clues that tell you when it’s better to pass on a particular animal:

Recently molted crabs and lobsters have shells with a grayish-to-green cast on their topsides and a lustrous white abdomen. That’s because the pigmentation of the shell comes from the animal’s diet, and they haven’t yet eaten enough to color the shells more richly.

Sometimes you will see a pinkish tinge, commonly referred to as rust, on the bottom of the crabs, which can indicate that they are getting close to molting. Before they do, they will reabsorb calcium from the shell, softening it. A telltale sign is that the shell will begin to appear slightly green again. They will bloat with water to loosen the shell and then will shed muscle mass to become small enough to squeeze out of it. Such crabs do not make for good eating.

MEAT4_Lobster bare_IMG_3393

 

So pick it right, and you’ll enjoy the aroma of cooked crustaceans, which is unique. The chemistry responsible for this redolence turns out to be the Maillard reaction, which normally requires a very high cooking temperature. But because the flesh of crustaceans contains a lot of sugars and amino acids (such as glycine, which tastes sweet) to counteract the salinity of seawater, the Maillard reaction occurs at an unusually low temperature. After you’re done feasting, save your crustacean shells. Collect them in the freezer until you have enough to make Pressure-Cooked Crustacean Stock. If you don’t have any shells, use whole shrimp (with heads on), which are relatively inexpensive and easy to find.

Why is the Turkey Still Pink?

You’ve covered your bases— the turkey was in the oven with a digital probe, or separated into white and dark meat, and then cooked to the perfect internal temperature. But when you begin carving your bird, you notice the devastating color that is sure to break the hearts of hunger-mad guests moments before Thanksgiving dinner is served: pink. No need to panic. If you’ve carefully cooked your bird, there are other reasons why you might see that hue.

Several phenomena can cause discoloration in cooked meat. By far the most common, and to some people the most off-putting, is the pink discoloration that frequently occurs in poultry and pork that have been over cooked to temperatures above 80 °C / 175 °F or so. This pink tint makes some people think that the meat is still slightly raw—a common complaint with Thanksgiving and Christmas birds. In pork, the pink hue may even lead diners to suspect that a sneaky cook has injected nitrites into the meat.

In fact, a pigment known as cytochrome is to blame. Cytochrome helps living cells to burn fat. At high temperatures, it loses its ability to bind oxygen and turns pink. Over time, the pigment does regain its ability to bind oxygen, and the pink tinge fades. That is why the leftover meat in the refrigerator rarely seems to have this unseemly blush the next day.

Pink discoloration can also come in other forms, such as spots and speckles. Nearly all of these blotches are the result of the unusual way that various protein fragments and thermally altered pigment molecules bind oxygen. None of them indicate that the meat is still raw or that it will make you ill. Nor do they implicate a sneaky cook.

-Adapted from Modernist Cuisine: The Art and Science of Cooking

Keeping it Fresh: Make Your Juice Last Longer

Jack LaLanne was the world’s first fitness superhero, the “godfather of fitness.” He also really loved juice. The Jack LaLanne Juicer turned juicing into a mainstream practice and juicers into common kitchen equipment.

Research studies have yet to validate claims that juicing is more beneficial than eating whole fruits and vegetables, with some studies suggesting that cleanses or excessive consumption can do more harm than good. Juicing, within reason, is a great way to incorporate these ingredients into your diet if you aren’t naturally inclined to eat your fruits and veggies. There is also something undeniably delightful about a glass of fresh-squeezed juice or the unique flavor combinations that can be created—orange-durian-strawberry-mango-kale, anyone?

Whether you juice for health or to please your palate, here is everything you need to know about how to help your juice stay fresh and vibrantly colored for as long as possible and about selecting the proper juicer for your needs.

KIT3_Fresh Squeezed_MG_9779

How Juicing Works

Juicing seems like a violent practice. There are gentler ways of retrieving flavor, such as stock making, when we coax flavors from these ingredients as they simmer. Juicing, however, is a form of violence on the biological building blocks of food so that we can unlock the liquid essence within. This means rupturing cells, but the cellular violence is well worth it—juicing yields incredibly rich flavors.

The rich flavors are fleeting, reserved for the freshest juice, which explains why the fresh stuff will always taste better than store-bought counterparts. When we make juice, sugars, acids, and peel oils combine to make the unmistakable flavor of fresh juice; however, over time, the acidity ruins the incredible flavor by destroying the aromatic peel oils over time.

Making the Most of Your Juice

Juicing is only half the battle. Freshly squeezed juice is fleeting. Although cellular destruction is required to release flavor-creating enzymes, as soon as cell walls are ruptured, the clock and biology will start working against you. The same oils that imbue juice with intense flavors and bright colors oxidize quickly. Aromas and flavors begin to diminish as flavor compounds break down.

When we cut open a piece of fruit, we know that it will eventually turn an unappetizing brown. The same applies for the liquid of those fruits. Many juices brown quickly in reaction to the trauma of juicing. Browning is a defense mechanism that plants use to prevent infection. To defend against germs, plants raise antimicrobial defenses. One mechanism is the release of the enzyme polyphenol oxidase (PPO) from tissue, which leads to the production of protective compounds, such as tannins, and to brown color. Pulp presents another issue. It typically browns long before the liquid. Pulp contains high concentrations of oxidizing enzymes and their molecular targets.

KIT3_Freeze finish_MG_3625

Browning may seem like a strange issue for those of us who are accustomed to purchasing juice at the store. Those juices, however, have already been treated to prevent color change and to preserve flavor. Although juicing is a relatively simple technique, these seven tips, used alone or in combination, will help you to improve your product and get the most out of your produce.

  • First, keep everything cold. Browning is caused by enzymes that respond to heat: for every 10°C/ 18°F drop in temperature, enzymatic activity falls by about half. You can safely chill most fruits to just above freezing before juicing them; however, avoid chilling subtropical produce, such as bananas, mangoes, avocados, and strawberries. Chilling these fruits can induce chilling injury, wherein low temperatures reduce the quality of produce.
  • Freezing produce prior to juicing will also prevent browning. Deep-freezing will permanently destroy the browning enzymes; however, flavor-creating enzymes might take a bit of a hit. If you decide to freeze your produce, thaw prior to juicing, unless you want to have a smoothie on your hands.
  • A three-minute dip in boiling water destroys browning enzymes. Blanching requires high temperatures, though, which will partially cook food by the time the enzymes break down.
  • Although some of us prefer a little pulp in our juice, filtering it out will eliminate the tissue that enzymes act on to form brown pigments.
  • Try lowering the pH of your juice. The more acidic the juice, the slower the enzymatic reactions that cause discoloration. High acidity also acts directly on brown pigments to lighten their color.
  • If you own a vacuum sealer, use it to help prevent oxidation. Although some oxygen is dissolved into the juice itself, vacuum sealing the juice will help slow down browning by removing oxygen.
  • Natural preservatives are another way to retain color and restore flavor. Ingredients like ascorbic acid (vitamin C), citric acid, malic acid, and honey will prevent browning, while essential oil, alpha tocopherol (vitamin E), or even a squirt of fresh juice from a different batch will preserve flavor.

Picking a Juicer

The type of juicier you own will also make an impact on your juice. Devout juicing advocates prefer cold-press juicers over equipment that introduces any heat to the process. In truth, the mechanisms that make each juicer work can affect the quality of your product, yield size, and even what types of produce you can juice.

Centrifugal-style juicers:

Centrifugal-style juicers are similar to blenders—they pulverize food with a broad, flat blade that sits at the bottom of a spinning mesh basket. The pulverized food is flung against the basket wall, where centrifugal force expels most of the juice from the pulp through the mesh and into a waiting container. These juicers handle both fruits and vegetables well, but look for machines that are designed to automatically dispel pulp deposits to make cleaning easier and to prevent clogs forming in the basket. With centrifugal force comes one major drawback: the friction of the force oxidizes the juice faster, which damages the flavor and color. You’ll also find that the yield from these machines is smaller than its Champion-style counterpart.

KIT3_Juicers centrifugal_Y2F1124

Champion-style juicers:

Champion-styles juicers are workhorses. Food is pushed down a chute onto a serrated, rotating blade. As fruits and vegetables pass through the blades, cell walls rupture, releasing their contents, which rapidly collect in a bowl. These appliances excel at separating solids from liquids: pulp is discarded into a separate waste receptacle. Champion-style juicers are also ideal for juicing relatively dry foods, like wheatgrass or leafy greens that can be difficult for other machines to pulverize. The primary shortcoming of this style of juicer is that the pulp still retains some liquid, which reduces overall yield.

KIT3_Juicers champion_MG_8374

Food presses:

Food presses or cold-press juicers (also known as masticating juicers) force liquids out mechanically by squeezing food between two hard, unyielding surfaces, one of which is perforated. These machines, which theoretically seem like a medieval torture device for fruits and vegetables, are often preferred by serious juicers because they use less heat. Juice presses are great for softer foods or for foods that have been softened with sugar, enzymes, or a little heat. In some presses, including cider presses, food is placed between flat plates, often between multiple layers of plates. Citrus fruit presses accommodate the shapes of citrus fruits by using convex and concave pressing surfaces. Muscle power fuels juice presses, which causes juice yields to vary depending on the user. If you enjoy pulp in you juice beware— your juice will contain fewer particles because food is compressed, as opposed to being torn or shredded.

KIT3_Juicers press_MG_6835

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Building a Better Turkey

When it comes to turkey, there are many different theories about the best way to prepare a bird. The topic can get downright philosophical with every side presenting evidence on behalf of a particular technique, leaving you to exit the fray with over a dozen methods, each one somehow better than the last. While some methods yield far better results than others, the only true loser is your dried-out bird. Here’s our guide, backed by science, for making a truly succulent turkey.

The Mechanics of Dark and White Meat

Structural differences between white and dark meat make succulence a particularly challenging goal. Meat gets its color from an oxygen-carrying protein called myoglobin, which naturally binds and shuttles oxygen throughout an organism’s body. Dark meat is comprised of slow-twitch muscles that are built for endurance and found primarily in the legs and thighs. These aerobic muscles require large quantities of oxygen-friendly myoglobin to help sustain prolonged use—such as long-distance running—hence their dark coloring. They also burn fat for fuel, so the meat ends up richer in flavor.

In contrast, if you were to look at a turkey breast under a microscope, you would see many light-colored, fast-twitch muscle fibers, geared for intense bursts of activity such as fluttering or scrambling across a road. These fibers work anaerobically and don’t burn fat, so few myoglobin proteins are present, resulting in a white, lean meat.

With different compositions and purposes, muscles cook at different temperatures—dark meat, for instance, requires higher cooking temperatures than white meat. That’s why preparing a turkey can get tricky. A Modernist approach is to cook each separately. For Thanksgiving, we like to create a confit of dark meat, brine the breast meat, and cook both sous vide at their respective times and temperatures. Cooking sous vide provides a precision-based strategy for maximizing juiciness, and it has an additional bonus: it frees up precious oven space for other dishes on your menu.

06_Baking_Turkey Cutaway_wo oven_IMG_7322

The Whole Turkey

It can be hard to imagine a Thanksgiving meal without an iconic, whole-roasted turkey. Maybe it’s a deep‑seeded, primal instinct based on millennia of roasting meats over a fire. Or perhaps it’s the nostalgia from that special moment when everyone in the kitchen holds their breath in unison to take in the aroma, the color of the skin, and the site of the steaming turkey as it emerges from the oven.

Whatever the reason, there are two issues that make roasting a whole turkey tricky. First, white and dark meat have to be baked together. Second, a crisp, golden skin requires temperatures that will leave the meat underneath undesirably dry. Suddenly, roasting a turkey becomes a juggling act between crispy skin and succulent meat, a task akin to an algebraic formula: if a turkey leaves the station in St. Louis at 15 mph, how long will it take to arrive in Denver with crispy skin and tender meat? Is there a definitive solution for roasting a whole turkey? Likely not. But we’d like to think that injection brining comes pretty close.

How Brines Work

On a fundamental level, brines modify meat proteins. When dissolved, salt dissociates into positively charged sodium ions and negatively charged chloride ions, which are the atoms that actually diffuse throughout your foods. Salinity is a measure of the concentration of these two ions, which equates to a specific ratio of salt to water. Ions flow from areas of high concentration to areas of low concentration, but, due to a shallow gradient in muscle tissues, the diffusion of dissolved salt tends to be quite slow, which is why it can take months to properly cure a ham.

Brining technically does not work via osmosis, as popular opinion suggests. If osmosis alone were at play, water would be drawn out of the meat, but brining works by pulling water into muscles. Chloride ions from dissolved salt diffuse into muscle fibers and accumulate along the surfaces of protein filaments. As these ions increase in number, they generate a negative charge that loosens and pushes neighboring filaments apart. This newly created channel provides enough space for water to enter the muscle, causing it to swell from the influx of ambient water. Ions further modify muscle proteins by causing them to bind tightly to water and resist shrinking as the meat cooks. Muscle will continue to swell until the salinity reaches 6%—after that, it shrinks and begins to lose water.

Brining is a slow process; salt diffuses through muscle roughly 100 to 1,000 times slower than heat conduction. As such, traditional brining can take days—the thicker the cut of meat, the longer it will take to brine. Protein is also found in skin, thus water molecules are bound and trapped there as well. As a result, the skin of brined meat can easily get soggy because of the time it takes for the brining process to work. Excess water can, then, lead to soggy skin and a rubbery texture. Enter injection brining.

MEAT6_Brine Injector_MG_9900

Injection Brining

Injection brining speeds up the process, turning a multiday event into an overnight task. This technique will give you more control over where your brine diffuses, allowing you to expose only the bird’s muscles to the brining solution.

The day before Thanksgiving, create a brine of 6% salt by turkey weight—a reasonable rule of thumb is to use at least as much water by weight as you have meat. Pull back the skin so that you only pierce the meat. Then, using a brining syringe, slowly inject the legs, breasts, and thighs. Inject the muscles evenly over the surface, leaving about an inch between injection sites. Turkeys can be large, so this may require dozens of injections. After your turkey is brimming with brine, let it rest overnight in your refrigerator. When you’re ready to roast the turkey, put it on a roasting rack over a drip pan. The rack allows air to circulate around the turkey, which helps amplify flavors and promote even browning of the skin.

Crispy Skin

Skin has an incredibly high moisture content—it’s about 70–80% water by weight. The science behind golden skin is simple: dry it out by removing moisture. For particularly thick skin, however, we like to add an extra step before cooking—don’t cover your brined turkey when you refrigerate it overnight. Instead, leave it uncovered until it’s time to put it in the oven. By doing so, you’re allowing the turkey’s skin to dry out so that it crisps better in the oven.

Crispy skin is also dependent on knowing the internal temperature of your turkey, so we like to combine the drying step with another equally simple step: tracking the oven’s temperature. Cover your turkey with aluminum foil, which will help prevent the skin from getting too dark, and then place it in the oven. Depending on your oven, bake the covered turkey between 191-204 °C / 375-400 °F. Once the turkey reaches an internal temperature of 68 °C / 155 °F, take the foil off, and crank your oven up to 232 °C / 450 °F in order to brown the skin. When the internal temperature reaches 71–72 °C / 160–162 °F, take the bird out of the oven. The turkey will continue to cook from residual heat to an internal, safe temperature of 73 °C / 163 °F. Note that for the most accurate temperature readings, you should insert your digital probe into the thickest parts of the bird, such as the turkey’s breast.

Patience is a Virtue

Once your turkey is out of the oven, it may be hard to avoid a display of turkey worship, but try to resist the urge to immediately carve your bird. Letting the meat rest can be one of the most difficult steps of the entire process, but it makes a considerable difference in flavor and texture. Ripe with brine, your finished turkey will be juicy. If you carve into it too soon, all of those glorious juices will end up on the cutting board instead of in the meat.

Why do we need to let it rest? Some popular theories suggest that the delay allows moisture, forced toward the meat’s interior during cooking, to travel back to the surface. But the slow diffusion rate of water actually prevents moisture from migrating during cooking and resting. In truth, degraded and dissolved proteins slightly thicken the natural juices as the turkey cools. The thickened liquid then escapes slower when the meat is sliced.

We recommend letting your turkey rest for 20 minutes. Use that time wisely by reheating vegetables made earlier in the day. Five minutes before service, gently warm your turkey in the oven.

One Final Debate: Stuffing

The subject of stuffing also happens to be fodder for debate. In one corner, there are devotees of cooking stuffing inside the turkey. In the other corner are those who insist that stuffing must be prepared separately.

If you want Thanksgiving to be memorable for all of the right reasons, make your stuffing in separate cookware, like a cast-iron skillet. Cooking stuffing inside of your turkey introduces food-safety issues—because turkeys are so thick, your stuffing will never reach a safe internal temperature, meaning you must contend with contamination issues from uncooked turkey drippings. Plus, you’ll miss out on the best part of stuffing: the crispy bits on the surface.

Ready for pie and leftovers? We have a recipe and more tips coming your way.

Cooking with Syllables: Carrageenan

What is Carrageenan?

History

From eggnog and soy milk to infant formulas and toothpaste, carrageenan is found everywhere. The word carrageenan may sound foreign and vaguely exotic, but it’s simply a generic term for a type of sugar extracted from various species of red seaweed. In Modernist cooking, it’s classified as an emulsifier, stabilizer, hydrocolloid (hydrophilic colloid), or gum, all of which function in some way to thicken or clarify ingredients, or to bind moisture. The term carrageenan has been around since at least 1889 and is derived from carrageen, circa 1829, which is a purplish, cartilaginous seaweed colloquially known as “Irish moss,” found off the coasts of North America and Europe. In fact, the seaweed gets its moniker from a small Irish fishing village, Carragheen, where it’s plentiful. Traditionally, the seaweed was boiled in sweetened milk to create a pudding. Simmering the seaweed unlocks the ingredient’s gelling properties. Its use, however, can be traced back even further to at least 400 CE, where it was used as a gelling agent and as an ingredient in homemade cold-and-flu remedies. Industrially, carrageenan is extracted chiefly from the red algae Chondrus crispus (class Rhodophyceae), but it can also be extracted from various species of Gigartina and Eucheuma.

FH4_Modernist Food Shelf_MG_6695

Function

Inherently vegetarian with no nutritional value, seaweed-based thickeners like carrageenan have new, modern applications. Most commonly, carrageenan can adjust the viscosity of dairy products like cheese, or it can serve as an emulsion stabilizer in salad dressings by keeping your oil and vinegar mixed. In more advanced applications, it will glue meat together, allowing for the creation of hot aspics and other seemingly contradictory foundations. Chemically, carrageenan is classified as a polysaccharide, a type of sugar. Its properties are varied and complex, but its basic function is to thicken and stabilize. It does this by forming large yet flexible matrices that curl around and immobilize molecules. Because of its inherent flexibility, carrageenans can form a variety of gels under a wide range of temperatures, but each type of carrageenan only becomes fully hydrated at a characteristic temperature. Some carrageenans can be hydrated without adding heat, while others must be brought to 85°C / 185°F or higher before saturation occurs, and a few have a hydration temperature that depends on the presence of other ions, the most common of which is calcium. Carrageenan actually comes in five varieties, classified by how much sulfate (SO4) it contains and its solubility in potassium chloride. Named after Greek letters, they are ι (iota), κ (kappa), λ (lambda), ε (epsilon), and μ (mu), however, only the forms iota, kappa, and lambda are used in Modernist cooking. All forms contain roughly 20–40% sulphate, which dictates how firmly (and whether) a gel will set, how the gel freezes and thaws, and how syneresis (the separation of water from its gel, also known as weeping) is affected. As the amount of sulfate increases, the strength of a gel decreases.

Safety

Recently, there has been some speculation over the safety of carrageenan. Carrageenan has been a focus for many mammal studies because of its potential to cause inflammation, ulceration, colitis, polyps, and colorectal tumors. Although such maladies are reported in animal studies, at the time of writing this connection has not been validated in humans because carrageenan’s molecular size and accompanying bonds prevent it from being digested naturally. To understand why carrageenan does not cause morbidity in humans, it’s important to differentiate between carrageenan and its degraded form, poligeenan. Poligeenan is the digested form of carrageenan and consists of molecular fragments small enough to pass from the digestive tract to the circulatory system. It is poligeenan that causes the many illnesses researchers describe in mammals, but current research has shown that the human digestive tract is limited in its ability to break down carrageenan into poligeenan. The primary pathway of human digestion, the alimentary canal, is, despite its placement, considered to be outside the body; a compound is not considered to be in the body until it moves from the digestive tract to the circulatory system. And, in order for any compound to affect human organs, such as the brain, liver, or heart, it must be small enough to cross the intestinal walls. Carrageenan is too large to do so, but poligeenan’s small size can. Not surprisingly, it has been postulated that carrageenan can be fragmented by natural digestive processes, but, to date, this has yet to be demonstrated in humans. In addition to carrageenan’s large size, its inherent bonds pose another challenge to the human digestive tract. Carrageenan is held together by β-glycosidic bonds, which are ubiquitous in the plant world, but most mammals, including humans, lack the proper enzymes to break them.

Recipes and Sourcing

Because of its utility, carrageenan is an ingredient that we use frequently, appearing in many recipes throughout Modernist Cuisine and Modernist Cuisine at Home. Carrageenan is used to create the creamy texture of our Pistachio Gelato and to stabilize our American Cheese Slices. Although you may not be able to find carrageenan on the shelves of neighborhood grocery stores, it’s easy to source online. If you’re ready to start testing this ingredient, try out our Pistachio Gelato recipe or Raspberry Panna Cotta in Modernist Cuisine at Home.

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Making your grill (or broiler) shine this summer

BY W. WAYT GIBBS
Associated Press

Compared to other basic cooking techniques, grilling is hard: the temperatures are high, timing is crucial and slight differences in the thickness or wetness of the food can dramatically affect how quickly it cooks.

Bad design choices by equipment makers—kettle-shaped grills with black interiors, for example—make it harder still. But if you’re willing to do some simple arithmetic or break out a roll of foil, you can reduce the guesswork and get better performance from your grill. Similar tricks work for broiling; after all, a broiler is basically just an inverted grill.

Every grill has a sweet spot where the heat is even. You know you’re cooking in the sweet spot when all of the food browns at about the same pace. In most situations, the bigger the sweet spot, the better. One notable exception is when you need to reserve part of the grill for cooking some ingredients more slowly or keeping previously cooked food warm.

If you find yourself continually swapping food from the center of your grill with pieces at the periphery, that’s a sure sign that your sweet spot is too small.

You can get an intuitive feel for where the edge of the sweet spot lies by looking at the heat from the food’s point of view. I mean that literally: imagine you are a hotdog lying facedown on the grill. If the coals or the gas flames don’t fill your entire field of view, then you aren’t receiving as much radiant heat as your fellow wiener who is dead-center over the heat source. If the falloff in the intensity of the heat is greater than about 10 percent, you’re outside the sweet spot.

You can use the table below to estimate the size of the sweet spot on your own grill. The 26-inch-wide gas grill on my deck has four burners with heat-dispersing caps that span about 23 inches. The food sits only three inches above the burner caps, so when all four burners are going, the sweet spot includes the middle 16 inches of the grill. But if I use only the two central burners, which are 10 inches from edge to edge, the sweet spot shrinks to a measly 5.4 inches, too small to cook two chicken breasts side by side. I can use this to my advantage, however, if I have a big piece of food that is thick in the middle and thinner at the ends, such as a long salmon fillet. By laying the fish crosswise over the two burners, I can cook the fat belly until it is done without terribly overcooking the slimmer head and tail of the fillet.

Sweet spots are narrowest on small grills, such as little braziers, kettles, hibachis, and the fixed grilling boxes at a public parks. If the sweet spot on your grill is too confining for all the food you have to cook, you can enlarge it in several ways.

If the grill height is adjustable, lower it. Bringing the food a couple inches closer to the heat can easily expand the sweet spot by 2 to 3 inches. The effect on the intensity of the heat is less than you might expect: typically no more than about a 15 percent increase.

If your grill is boxy in shape, line the sides with foil, shiny side out. Your goal is to create a hall of mirrors in which the heat rays bounce off the foil until they hit the food. A hotdog at the edge of the grill then sees not only those coals that are in its line of sight, but also reflections of the coals in the foil-lined side of the grill.

The foil trick unfortunately doesn’t work well on kettle grills because their rounded shape tends to bounce the radiant heat back toward the center instead of out to the edges. But if you can find a piece of shiny sheet metal about 4 inches wide and 56 inches long, you can bend the metal into a reflective circular ring and build the coal bed inside of it. All food within the circumference of the ring should then cook pretty evenly.

Jury-rigging a grill in this way wouldn’t be necessary if grills came shiny on the inside and we could keep them that way. But, presumably because nobody likes to clean the guts of a grill, the interiors of most grills are painted black, the worst possible color for a large sweet spot. A black metal surface doesn’t reflect many infrared heat rays; instead it soaks them up, gets really hot, then re-emits the heat in random directions.

Someday, some clever inventor will come up with a self-cleaning grill that has a mirror finish inside, and the sweet-spot problem will simply vanish.

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HOW BIG IS YOUR SWEET SPOT?

For grills, measure the width of the coals or gas burners (including any burner caps that disperse the heat). Then measure the distance from the top of the coals or burners to the upper surface of the grill grate. Find the appropriate row in the table to estimate the size of the sweet spot, centered over the heat source. This table assumes a nonreflective grill.

To calculate the sweet spot of an electric broiler — which is the ideal vertical distance between the top of the food and the broiler element — measure the distance between the rods of the heating element. Multiply that measurement by 0.44, then add 0.2 inches to the product. For example, if the rods are 2.4 inches apart, the sweet spot is 1.25 inches from the element to the top of the food.

Width of heat source (inches) Height of the food above the heat source (inches) Width of grill sweet spot (inches)
14 3 8.1
14 4 7.7
14 5 7
16 3 9.9
16 4 9
16 5 8.3
20 3 13.2
20 4 12
20 5 11.20
23 3 16.1
23 4 15
23 5 13.3
29 3 21.8
29 4 19.7
29 5 18.9

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Photo credit: Ryan Matthew Smith / Modernist Cuisine, LLC

The Maillard Reaction

One of the most important flavor-producing reactions in cooking is the Maillard reaction. It is sometimes called the “browning reaction” in discussions of cooking, but that description is incomplete at best. Cooked meats, seafood, and other protein-laden foods that undergo the Maillard reaction do turn brown, but there are other reactions that also cause browning. The Maillard reaction creates brown pigments in cooked meat in a very specific way: by rearranging amino acids and certain simple sugars, which then arrange themselves in rings and collections of rings that reflect light in such a way as to give the meat a brown color.

The important thing about the Maillard reaction isn’t the color, it’s the flavors and aromas. Indeed, it should be called “the flavor reaction,” not the “browning reaction.” The molecules it produces provide the potent aromas responsible for the characteristic smells of roasting, baking, and frying. What begins as a simple reaction between amino acids and sugars quickly becomes very complicated: the molecules produced keep reacting in ever more complex ways that generate literally hundreds of various molecules. Most of these new molecules are produced in incredibly minute quantities, but that doesn’t mean they’re unimportant.

The Maillard reaction occurs in cooking of almost all kinds of foods, although the simple sugars and amino acids present produce distinctly different aromas. This is why baking bread doesn’t smell like roasting meat or frying fish, even though all these foods depend on Maillard reactions for flavor. The Maillard reaction, or its absence, distinguishes the flavors of boiled, poached, or steamed foods from the flavors of the same foods that have been grilled, roasted, or otherwise cooked at temperatures high enough to dehydrate the surface rapidly — in other words, at temperatures above the boiling point of water. These two factors, dryness and temperature, are the key controls for the rate of the Maillard reaction.

High-temperature cooking speeds up the Maillard reaction because heat both increases the rate of chemical reactions and accelerates the evaporation of water. As the food dries, the concentration of reactant compounds increases and the temperature climbs more rapidly.

caramelized carrots 4

Temperatures need to be high to bring about the Maillard reaction, but as long as the food is very wet, its temperature won’t climb above the boiling point of water. At atmospheric pressure, only high-heat cooking techniques can dry out the food enough to raise the temperature sufficiently. It’s not the water that stops the reaction, but rather the low boiling point at normal, sea-level pressure. In the sealed environment of a pressure cooker, the Maillard reaction can, and does, occur. This is something we exploit when making soups, like in our Caramelized Carrot Soup, or purees, like the broccoli puree in our Brassicas recipe. Adding baking soda to the pressure cooker raises the food’s pH (making it more alkaline), which also helps. Chinese cooks often marinate meat or seafood in mixtures containing egg white or baking soda just before stir-frying.

So, in boiled, poached, and steamed muscle foods, an entirely different set of aromas dominates the flavor. Drying and browning the surface first will, however, allow the reaction to proceed slowly at temperatures below the boiling point of water. This is why we sear frozen steak before cooking it in a low-temperature oven. Searing food before vacuum sealing and cooking sous vide can add depth to the flavor of sous vide dishes. This step should be avoided for lamb, other meats from grass-fed animals, and a few other foods in which presearing can trigger unwanted reactions that cause off-flavors and warmed-over flavors to form when the food is later cooked sous vide. We recommend searing those foods after cooking them sous vide.

Blowtorch-cropped

One of the challenges to getting the Maillard reaction going is getting the surface hot and dry enough without overcooking the underlying flesh, or at least overcooking it as little as possible. Cooks have developed several strategies to this end, some simple and some fairly baroque.

One strategy that works well is to remove as much water from the surface of the meat as possible before cooking it (via blotting or drying at low temperature). Fast heating using deep fryers, super-hot griddles and grills, and even blowtorches are also helpful tactics, such as when we deep-fry chicken wings.

You might think that raising the temperature even higher would enhance the Maillard reaction. It does up to a point, but above 180 °C / 355 °F a different set of reactions occur: pyrolysis, also known as burning. People typically like foods a little charred, but with too much pyrolysis comes bitterness. The black compounds that pyrolysis creates also may be carcinogenic, so go easy on charring your foods for visual appeal.

Adapted from Modernist Cuisine

Is It Safe to Cook with Plastic?

Since writing Modernist Cuisine and Modernist Cuisine at Home, we’ve been asked many times to comment on the safety of cooking in plastic bags. Many of our sous vide recipes, from our Sous Vide Salmon and Rare Beef Jus to our Cranberry Consommé and Scrambled Egg Foam, require vacuum-sealing or using a zip-top bag. Similarly, many of our recipes that utilize microwaves, such as our Microwaved Tilapia, Eggplant Parmesan, and Microwave-Fried Herbs, require plastic wrap.

According to the latest research, the safest plastics for use with food are high-density polyethylene, low-density polyethylene, and polypropylene. Virtually all sous vide bags are made from these plastics, as are most brand-name food storage bags and plastic wraps such as Saran wrap. Polyethylene is widely used in containers for biology and chemistry labs, and it has been studied extensively. It is safe.

Less expensive, bulk plastic wraps sold to the catering trade are not as safe, however. These products are commonly made from polyvinyl chloride (PVC), which can contain harmful plasticizers that have been shown to leach into fatty foods such as cheese, meat, and fish. Legitimate concerns exist about food exposed to these plastics at high temperatures. Polyethylene-based plastic wraps are available at only slightly higher costs and do not raise such concerns. An easy way to spot the difference is to check that your cling wraps or plastic bags are rated microwave-safe. Bags and wraps made form polyethylene are generally microwave-safe, whereas those that contain polyvinyl chloride plastics generally are not.

Many professional kitchens use clear, rigid, plastic storage containers that are made from polycarbonate. While they are currently approved for food use, these plastics also may be a cause for concern because they contain bisphenol A (BPA), a chemical that can disrupt hormone activity and leach into foods and beverages. Cracks and crazing due to wear and tear increase the rate at which BPA leaches out of polycarbonates.

The bottom line is that bags made expressly for cooking sous vide are perfectly safe—as are oven bags, popular brands of zip-top bags, and stretchy plastics such as Saran wrap. If you remain hesitant to try cooking sous vide due to concerns over plastic, you can always use canning jars instead, but beware that cooking times will be longer.

—Adapted from Modernist Cuisine and Modernist Cuisine at Home

What Is Xanthan Gum?

Some people are suspicious of ingredients with unfamiliar names, such as xanthan gum. We are frequently asked, “Aren’t your dishes chock-full of chemicals?” Well, yes, but all foods are, including the most natural and organic ones. But nearly all of those chemicals are derived from natural ingredients or processes that have been used for decades.

First discovered by USDA scientists in the 1950s, xanthan gum is fermented by plant-loving bacteria, characterized by sticky cell walls. It is no less natural than vinegar or yeast. We think xanthan gum is one of the best discoveries in food science since yeast.

It is used as a thickener or stabilizer in a wide variety of foods found on grocery store shelves. Many canned or prepared products contain xanthan gum: salad dressings, sauces, soups, and baked goods — particularly those that are gluten-free because xanthan gum can perform some of the same functions as gluten.

Xanthan gum is one of the most useful food additives around; it is effective in a wide range of viscosities, temperatures, and pH levels. It is easy to use, has no taste, and generally works quite well. And it can thicken liquids at extremely low concentrations – as little as 0.1% by weight can yield a thick liquid, and 0.5% by weight can make a thick paste (this is why it is best to weigh out xanthan gum with a digital scale rather than use volumetric measurements). Traditional thickeners like flour typically require far larger amounts to do a similar job. The quantity matters because the more thickener you have as a fraction of the total mixture the more likely it is to impose an undesirable texture and inhibit flavor.

Ready to try xanthan gum? Take a look at our recipe library for recipes for Spinach Pesto, Jus Gras, and Wasabi Cream. Check back later this month, when we’ll be showcasing more recipes from Modernist Cuisine at Home that use xanthan gum.

adapted from Modernist Cuisine and Modernist Cuisine at Home