The Secret to the Perfect Soft-Boiled Egg

A perfect soft-boiled egg is a thing of beauty: a yolk with the texture of sweet condensed milk surrounded by a white that is tender but not runny. But for generations, great cooks have differed on how to achieve this state of perfection reliably.

Some authorities say you should drop a whole egg into boiling water for about three minutes — a bit longer if the egg is extra-large — and then gently peel away the shell. That can leave the yolk too runny, however. And when the egg is peeled, it’s all too easy to tear the tender white into a mess.

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The legendary Julia Child advocated a six-minute boil (for large eggs starting at room temperature, or a minute longer if chilled), followed by a rinse with cold water before and also during peeling. That certainly works for the white, but often overcooks the center.

The French food scientist Hervé This argued some years ago that temperature, not time, is all that matters to the egg—cook it to 65 °C / 149 °F, and the result will be heavenly no matter how long it sits in the water. Or so it was thought. For a while, the “65°C egg” was all the rage at high-end restaurants.

But more recent research by the food chemist Cesar Vega , an editor and coauthor of the 2012 book The Kitchen as Laboratory, conclusively showed that both time and temperature matter. Moreover, the white and the yolk contain different blends of proteins, so the white gels at a higher temperature and a different rate than the yolk does. Vega’s rigorous experiments have armed scientifically inclined chefs with the information they need to cook eggs to whatever texture they like.

When the chefs in our research kitchen make soft-boiled eggs, they use a four step process that involves a blowtorch or liquid nitrogen. Here is a simpler version better suited to the home kitchen. You’ll need a pot of boiling water, a bowl of ice water, a temperature-controlled water bath, and, if you plan on peeling the eggs, a toaster oven.

The first step is to set the egg whites quickly by submerging them completely in a pot of rapidly boiling water for three minutes and 30 seconds, 15-30 seconds less if you like the whites quite loose, as our research chefs do, or 15—30 seconds longer if you prefer the whites fully set. When the time is up, plunge the eggs into the ice water to cool them completely.

Next, cook the yolks to a syrup-like thickness by submerging the eggs in a 64 °C / 147 °F water bath for 35 minutes; it’s important that the water temperature doesn’t change more than a degree or two during cooking. Dry the eggs thoroughly with paper towels. They are now ready to place in egg holders, top, and eat with a spoon. (If you have a Dremel or similar handheld rotary tool, use a thin grinder bit to top the eggs like a pro.)

Alternatively, you can make the eggs easier to peel by drying the shells in a toaster oven. Use a medium-dark toaster setting, and let the eggs heat for two to three minutes to make the shell hot and brittle. It will then readily flake away to reveal a flawless white beneath. Remember to remove the thin skin around the white if it doesn’t come off with the shell.

You can make these eggs in advance and later reheat them in a 60 °C / 140 °F bath for 30 minutes.

By adjusting the temperature of the cooking bath or the time the eggs are in it, you can achieve all kinds of delicious results and reproduce them flawlessly time after time. Prefer a yolk that is more like honey? Let the egg sit in a 65 °C bath for 45 minutes. For a runnier center, try our recipe for Liquid Center Eggs.

Or try cooking them in a 72 °C / 162 °F bath for 35 minutes (you can skip the boiling step). The yolk will then set just firmly enough that you can peel away the white to obtain a perfect yellow sphere, which makes a striking garnish or dumpling-like addition to a soup.

It’s remarkable how advances in science and precision cooking have given new life to this versatile food.

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.

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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.

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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

Modernist Cuisine at Home Nominated for Awards

We are thrilled to announce that Modernist Cuisine at Home has been nominated for a James Beard Award in the “General Cooking” category. Also nominated in that category are Canal House Cooks Every Day and What Katie Ate.

In 2012, winning the James Beard Award for Modernist Cuisine in the categories “Cookbook of the Year” as well as “Professional Cookbook” was one of the highlights of our year. We are very much looking forward to the award ceremonies. The award winners for cookbooks will be announced on May 3, 2013.

Modernist Cuisine at Home was also recently nominated for an International Association of Culinary Professionals (IACP) award in the category of “Food and Beverage, Reference/Technical.” In that category, The Art of Fermentation and Mastering Artisan Cheesemaking were also nominated. Last year, Modernist Cuisine won three IACP awards—in the “Professional Kitchen Books” category, the “Design” category, and also their newly created “Visionary Achievement” category.

On top of that, our CHOW.com video series, MDRN KTCHN, was nominated in the “Short Video Series” category. Kitchen Confidence on Food52.com and Master Class on Saveur.com were also nominated.

We are deeply honored to have been nominated for both the James Beard and IACP awards. Congratulations and best of luck to all other nominees!

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